School Science Lessons
2024-12-26
Carbon C
(topicIndexCarbon)
Please send comments to: j.elfick@uq.edu.au
Contents
Carbon
Carbon compounds
Carbohydrates
Gases containing carbon at STP
Sugars
Hydrocarbons
16.1.0 Carbon
Carbon, C (Latin carbon coal), lump, rods, powder, lamp black, acetylene black, wood charcoal,
activated carbon / charcoal, activated charcoal, decolorizing charcoal, graphite, colloidal carbon, carbon mineral lump
(coke is left when coal is heated without air), used for blowpipe work, charcoal may contain wood ash mainly potassium carbonate,
in soft "lead" pencils), non-metal network solid, has two natural crystalline forms: diamond and graphite.
Atomic number: 6, Relative atomic mass: 12.011, RD 2.25 (graphite), MP: 3730 oC (sublimes), bp: 4830 oC, Specific heat capacity 711 J kg-1 K-1 (graphite), 519 J kg-1K-1 (diamond).
Carbon, black central electrode of torch (flashlight) batteries.
Carbon nanotubes, Activated carbon, Darco KB and KB-B activated carbon, for purifying highly coloured liquids.
Low cost: activated charcoal from pharmacies and stores selling pet fish, goldfish and aquariums.
Carbon
Carbon Table of the Elements.
Carbon RSC
Carbon: 35.3.0,(Geology)
Carbon / nitrogen ratio: 9.14.3 C/N ratio, (Experiment)
Allotropes, sulfur, carbon: 7.9.4.2
Carbon, "Aquadag": 35.3.6 (colloidal graphite)
Carbon, Burn to make carbon (Primary): 5.43 (Experiment)
Carbon, Soot from a candle flame: 8.1.16
Charcoal: 16.1.1, (Experiments)
Coal, Prepare gases from coal: 16.1.2, (Experiment)
Coal, Coal dust explosions: 35.3.2 ,(See: 3.), (Geology).
Coal seam gas, CSG, and coal to liquid, CTL, projects: 37.1.2
Diamond
Diamond: 35.3.3 (Geology)
Graphite: 35.3.4 (Geology)
Graphite, Allotropes, sulfur, carbon: 7.9.4.2
Heat glucose to form carbon: 16.1.3
Heat starch to form carbon: 16.1.4
Radioactive carbon dating: 2.10.1
16.2.0 Carbon compounds
Carbon dioxide CO2
Carbon disulfide, CS2: 16.4.2
Carbon monoxide, C≡O (note triple bond): 16.4.3
Carbon tetrachloride CCl4, Tetrachloromethane.
Carbonated beverages, fizzy drinks, soft drinks, sports drinks: 3.10.0
Carbonic acid, soda water: 3.9.0
Carbonyl, >C=O, organic compound functional group.
Hydrocarbons
Lipids
RuBisCo C5H12O11P2
Rubrofusarin C15H12O5
Sugars
Tannins
Experiments
Acids: Concentrated acids with a non-metal, carbon: 12.3.5
Acids: Dilute acids with non-metals, carbon, sulfur: 12.4.12
Carbonates (Experiments)
Freezing point depression of carbonated water, cola: 24.1.05
Glucose: Prepare glucose with starch (Experiment)
Glucose: Prepare glucose with sugar (Experiment)
Heat glycerine with sugar to form carbon: 12.1.7
Heat starch to form carbon: 16.1.4
Jet black
"Lead pencils": 35.3.5 (Geology)
Organic carbon soil test: 6.10.6
Prepare gases from wood: 3.99 (Experiment)
Tests for carbonates / bicarbonates: 12.11.7
12.1.11 Butyl chloride rainbow reactions
16.3.0 Carbohydrates
Carbohydrates were compounds such as aldoses and ketoses, stoichiometric formula Cn(H2O)n, so "hydrates of carbon".
Nowadays, carbohydrates include monosaccharides, oligosaccharides, polysaccharides, and substances from monosaccharides.
1. by reduction of the carbonyl group, >C=O (alditols), Carbonyl, >C=O, organic compound functional group.
2. by oxidation of one or more terminal groups to carboxylic acids, e.g ethanoic acid, CH3COOH.
3. by replacement of hydroxy groups by a hydrogen atom, amino group, thiol group, and other groups, derivatives of these compounds.
Carbohydrate acids: D-gluconic acid, CH2(OH)(CHOH)4COOH, produced by fungi.
D-glucuronic acid, C6H10O7, occurs in gums, forms glucuronides.
d-gluconic acid, d-glucuronic acid, is food additive E574, anti-caking agent, sequestrant.
Sold as: D-Glucuronic acid, Glucodiuronic acid, C6H10O7.
Experiments
Burn carbohydrates, fats and proteins: 9.1.1
Reactions of carbonates: 12.15.0
Tests for carbonates: 2.11.7
Tests for carbohydrates, Molisch's test: 9.3.7
16.4.0 Gases containing carbon at STP
13.3.0 Prepare gases with gas generation apparatus, (Experiment)
Carbon dioxide CO2
16.4.2 Carbon disulfide, CS2
16.4.3 Carbon monoxide, CO
16.4.12 Trichloroethane, (methyl chloroform), CH3CCl3
16.4.13 Trichloromethane, (chloroform), CHCl3
16.5.0 Sugars
16.5.1 Sugars
16.5.2 Monosaccharides, List
16.5.3 Monosaccharides, D sugars and L sugars
16.5.4 Disaccharides,
16.5.5 Haworth projection
16.5.6 Oligosaccharides
16.5.7 Polysaccharides
16.5.8 Prepare rock candy crystals
16.5.9 Sugar acids, classes
16.6.0 Hydrocarbons
Hydrocarbons, hydrocarbon chains, -C-C-C-, bond angle 109.5o, -CH2-CH2-CH2-
Hydrocarbyl groups, methyl -CH3. ethyl -C2H5, phenyl -C6H5
Short chain hydrocarbons are in flower scents and fruits and also bad smelling molecules, e.g diallyls and mercaptans.
Long chain hydrocarbons, especially alkanes, are in cuticle waxes.
Allicin, Diallyl sulfide, Diallyl disulfide, Dodecane, Hentriacontane, Methyl mercaptan, Naphthalene, Octan-1-ol, Pentadecane, Ranunculin
Aliphatic hydrocarbons
16.3.1 Alkanes CnH2n+2, paraffins
Methane CH4
16.4.4 Ethane, C2H6
16.4.11 Propane, C3H8
16.4.1 Butane, C4H10
16.4.10 Pentane, C5H12
16.4.8 Hexane, C6H14
16.4.7 Heptane, C7H16
16.4.9 Octane, C8H18
16.4.1 Alkenes, CnH2n, olefins
16.4.5 Ethene, (ethylene), C2H4
Hexene
16.7.0 Alkynes CnH2n-2, acetylenes
16.4.6 Ethyne, (acetylene), C2H2
Aromatic hydrocarbons, arenes
Benzene, C6H6
Naphthalene, C10H8
Toluene, C7H8
Hydrocarbon solvents, Flammable: 7.9.22, (See 6.)
Tests for gases from burning hydrocarbons: 16.4.6.0
Tests for unsaturated hydrocarbons: 9.3.20
See diagram 16.1.1: Alkanes, alkenes, alkynes
Ajugose
Ajugose, C36H62O31, hexasaccharide, sweet, It occurs in Ajuga, verbascum, and seeds of Vicia, Vigna mungo.
Apiose
Apiose, D-Apiose, C5H10O5 monosaccharide, in parsley, (Petroselenum crispum) as the flavone glucoside Appiin
It occurs in polysaccharides of aquatic plants, and in Lemna, Posidonia, Wolffia, and Zostera.
Arabinose
Arabinose, L-Arabinose, C5H10O5, pectinose, pectin sugar, in plant glycosides, hemicelluloses and gums.
Sugar component of anthraquinone glycosides of Aloe.
Arabinose (Table).
Arabinose is sold as L-(+)-Arabinose.
L-Arabinose is found in or produced by Saccharomyces cerevisiae.
Deoxyribose
Deoxyribose, Deoxy-D-ribose, Desoxyribose, C5H10O4.
Sugar component of desoxyribonucleic acid, DNA, prepared by acid hydrolysis of DNA.
16.1.8 Nucleosides, nucleic acids, DNA, RNA.
9.4.0H DNA and RNA.
Deoxyribose is found in or produced by Saccharomyces cerevisiae.
Digitalose
Digitalose, C7H14O5, in cardiac glycosides, in common foxglove (Digitalis purpurea).
Fructose
See diagram 16.2.8.3 : Fructose.
C6H12O6, Fructose, D form, but laevorotatory, so "L-fructose", sold as: "D-(-)-Fructose, D-Levulose, Fruit sugar", pure honey.
Fructose (Table).
Fructose occurs as free sugar in phloem and nectar, in oligosaccharides, e.g. sucrose, twice as sweet as glucose.
Tests for reducing sugars gives no values for fructose.
D-Fructose, C6H12O6, D-Fructopyranose, sweetening agent, monosaccharide, in sweet fruits and honey and soluble in water and alcohol
. It is used as a preservative and in intravenous feeding.
Galactose
Galactose, C6H12O6, L-Galactose, Brain sugar, Cerebrose, sold as: D-(+)-Galactose.
See diagram 16.3.1.4B : Galactose.
Galactose (Table).
In hemicelluloses of pectins, gums, mucilages, in some glycosides, sugar of seaweed polysaccharides, Porphyra.
Repeating disaccharide unit, "poly β-galactose--β-acetylglucosamine-6-sulfate", in bovine cornea.
Bacteroides thetaiotaomicron in the colon harvests additional energy from otherwise indigestible sugars, e.g. galactose and mannose.
Tests for reducing sugars gives no values for galactose.
Caramelization temperature of galactose is 160 oC.
D-Galactose, C6H12O6, D-Galactopyranose, isa naturally occurring sugar, and it occurs in a dairy products.
It is not commonly used as a sweetener, because it is only about 30% as sweet as sucrose.
It is used in some common vaccines and non-prescription products.
Galacturonic acid
Galacturonic acid, C6H10O7, in polymers in plant cell wall pectin, in saponins, Marchantia moss.
Gentianose
Gentianose, C18H32O16, sweet, trisaccharide, reserve carbohydrate
It occurs in Gentiana rhizomes.
Gentiobiose
Gentiobiose, C12H22O11, bitter, two beta-D-glucose residues linked, in plant glycosides, e.g. amygdalin.
Glucosamine
Glucosamine, C6H13NO5, (2-amino-2-deoxyglucose), sugar in animal chitin and mucoprotein
It is a monosaccharide amino sugar, from fermentation of grain, anti-arthritic and may help relieve symptoms of arthritis.
However, scientific evidence is not conclusive and it may interact with warfarin, so large doses are not advised.
Glucosamine dietary supplements should be taken with food to avoid upset stomach, heartburn and diarrhoea.
Glucosamine occurs in bacteria and fungi cell wall, Aspergillus, in glycoproteins of plant seeds, Phaseolus.
Glucuronic acid
Glucuronic acid, C6H10O7, in plant gums and mucilage, in Miquel's Wintergreen
Gaultheria miqueliana.
Hamamelose
Hamamelose, C6H12O6, with tannin in bark of witch hazel (Hamamelis virginiana), in leaves of Primula.
Inulin
Inulin, C228H382O191, occurs in plant tubers and roots naturally occurring, indigestible and non-absorbable oligosaccharide fructan dietary fibre
It is stored in roots or rhizomes instead of starch, and it is used in processed foods to replace sugar and fat.
It occurs in roots and tubers of chicory, Jerusalem artichoke, Dahlia, sunflower, wheat, rye, onion, bananas, garlic, asparagus, and barley kernels.
Inulin stimulates the growth of beneficial bacteria in the colon to protect against pathogens and toxins, which can cause inflammation and cancer.
Prebiotic fermentation of inulin leads to an increase in short-chain fatty acids and lactic acid production, reducing colonic pH and anticancer activity.
See diagram : Inulin compound
Lactose
Lactose, C12H22O11, milk sugar (disaccharide: glucose + galactose), in human and cow's milk, milk sugar, not as sweet as sucrose
Lactase decomposes lactose molecules to α-glucose and β-galactose, nutrient for infants and convalescents, occurs in Forsythia flowers.
Achras fruit
Lactose, C12H22O11.H2O, milk sugar lactitol, food additive E966, sweetener, texturizer, humectant, E279
Lactose, disaccharides: 16.3.1.4.0
Lactose intolerance: 19.2.4
Ice cream: 16.2.10
Prepare lactose from milk or whey using immobilized lactase: 4.4.4
Tests for glucose, urine test: 19.1.20.4
Laminaribiose
Laminaribiose, C12H22O11, sweet, in Colchicum petals, some plant glycosides, made from seaweed polysaccharide laminarin.
antiseptic, formed from caramelization of glucose.
Lepidimoide
Lepidimoide, C12H17NaO10, sweet, in cress, sunflower and buckwheat seeds, Lepidium.
Lychnose
Lychnose, C24H42O21, tetrasaccharide, reserve carbohydrate, sweet, in Lychnis, Dianthus, in Caryophyllaceae, woody plants, cucurbits and legumes.
Maltose
Maltose Oligosaccharides
Maltose, malt sugar, disaccharide, produced by hydrolysis / digestion of starch, 2 glucose residues
Disaccharides: 16.3.1.4.0
Food additive, E965 Maltitol and maltitol syrup (from maltose) (sweetener, humectant, stabilizer)
Breakdown starch during germination: 9.112
Breakdown starch to sugars (laundry starch): 3.95
Hydrolysis of starch by salivary amylase): 9.5.4
Non-enzymatic browning, caramelization: 19.3.4.3
Sense of taste, the gustatory system: 9.246
Tests for activity of diastase: 9.3.9
Tests for glucose, urine test: 19.1.20.4
Tests for sugars: 9.3.17
Tests for starch with Fehling's solution: 9.142.3
Tests for hydrolysis of starch: 9.6.5
Yeast, fermentation, brewing, beer: 16.7.11
Yeast, Ferment sucrose with yeast: 12.1.20
Mannose
Mannose, C6H12O6, in plant polysaccharides, in natangura palm (Metroxylon warburgii).
Mannose (Table).
Mannitol, CH2OH(CHOH)4CH2OH, from mannose or fructose, sugar in fungi and brown algae, food sweetener.
Sold as D-Mannitol, Mannite, C6H14O6.
Early purple orchid (Salep dondurma), fox testicle, ground tuber in turkish ice cream "dondurma" (glucomannams: glucose + mannose).
Sold as: D-(+)-Mannose from wood, D-Mannopyranose, L-(-)-Mannose.
Melezitose
Melezitose, C18H32O16, sweet, nonreducing trisaccharide sugar, in pine manna, Pinus, Pseudotsuga, aphids Cinara honeydew attracts ants, bees.
Pentosans
Pentosans are polysaccharides composed of pentose sugars, in grains, fruits, and legumes, used to increase water holding capacity of flour so bread takes longer to go stale.
Pentosans contain long chains of 1,4-beta-d-xylopyranose and single 1,2- or l, 3-alpha-l-arabinofuranose side groups.
Quercitrin
Quercitrin, C21H20O11, Fagopyrum, (Quercus --> Quercetin and Rhamnose).
Quercitrin, in allspice herb, a glycoside formed from the flavonoid quercetin and the deoxy sugar rhamnose, is in the dye quercitron.
Deoxy sugar rhamnose in alder buckthorn (Rhamnus frangula), frangula bark, a former laxative.
Raffinose
Raffinose, C18H32O16, gossypose, trisaccharide, in plant leaves, Vicia, sugar beet, cotton seed, reserve carbohydrate.
Rhamnose
Rhamnose, C6H12O5, deoxy sugar in many plant glycosides and polysaccharides, especially pectins, gums, very sweet taste.
Ribose
Ribose, C5H10O5, D-ribose, in ribonucleic acids, and metabolic ATP, adenosine.
Ribose (Table).
See diagram 16.3.2.8.2 : Ribose, deoxyribose.
Ribose has all the hydroxyl groups on the same side in the Fischer projection.
Industrial: D-(-)-Ribose, 099%, CAS Number 50-69-1, Empirical Formula C5H10O5, Molecular weight 150.13.
Adenosine, C10H13N5O4, (adenine + ribose), adenine riboside, adenine-9-β-D-ribofuranoside.
Guanosine, C10H13N5O5, nucleoside, (guanine + D-ribose).
Ribulose
Ribulose, C5H10O5, D-Riboketose, arabinoketose, in photosynthesis carbon cycle, sweet tasting.
Ribulose (Table).
See diagram : D-ribulose and L-ribulose.
Ribulose is a ketopentose so has a ketone functional group.
It is an artificial sweetener, but not very sweet.
The enantiomers (mirror image molecules, pair of optical isomers), are D-ribulose and L-ribulose.
Ribulose-5-phosphate-3-epimerase, catalyses L-ribulose 5-phosphate <==> L-xylulose 5-phosphate.
Ribulose is sold as: L-Ribulose, L-Adonose, also D-Ribulose.
RuBisCo C5H12O11P2
Rubisco
See: 6.5.1 Photosynthesis, 3 types of photosynthesus, RuBisCo
RuBisCo, rubisco, C5H12O11P2, ribulose-1-5 biphosphate carboxylase oxygenase, enzyme for first step in carbon fixation by plants.
Ribulose bisphosphate carboxylase large chain (Gnetum parvifolium) catalyzes two reactions:.
1. Carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation.
2. Oxidative fragmentation of the pentose substrate in the photorespiration process.
Both reactions occur simultaneously and in competition at the same active site.
Sold as: Rubisco, powder from spinach.
Rubrofusarin
Rubrofusarin, rubrafusarin, (5,6-Dihydroxy-8-methoxy-2-methyl-benzo[g]chromen-4-one), C15H12O5, a benzochromenone, biological pigment, polyketide, aromatic ether, phenol, orange polyketide pigment,
in Fusarium graminearum, anti-cancer, anti-mycobacterial, mycotoxin, anti-estrogenic.
Sorbose
Sorbose, C6H12O6, in pectins of ripe passionfruit, (Passiflora edulis), in fruit of mountain ash (Sorbus aucuparia), in ascorbic acid metabolism.
Sorbose (Table).
Stachyose
Stachyose, D-Stachyose, Lupeose, C24H42O21, sweet, a tetrasaccharide of two D-galactose units, an oligosaccharide
It occurs in human milk, green beans, soybeans, Stachys roots, Jasminum, Lupinus, and in Fraxinus.
See diagram 16.3.1.4 : Stachyose, acarbose.
Stachyose (tetrose: fructose + galactose + glucose + galactose, i.e. raffinose + galactose)
Sucrose
Sucrose, D-Sucrose, cane sugar, "sugar", C12H22O11, sweet, disaccharide formed by glucose and fructose units
It occurs in green plants especially nectars, sugar cane.
Sugars Sucrose, (Experiments)
3.1.17 Prepare sugar crystals from brown sugar
3.1.2 Prepare sugar crystals from sugar cane juice
3.1.3 Sucrose octoacetate
3.1.4 Sucrose with borax
3.1.5 Sucrose with sodium hydrogen sulfate
3.1.6 Ferment sucrose with yeast
16.5.8 Prepare rock candy crystals
Monosaccharides, D and L sugars
Trehalose
Umbelliferose
Verbascose
Polysaccharides
Pentosans
Trehalose
Trehalose, C12H22O11, disaccharide, mycose, mushroom sugar, sweet, in fungi, some prevent desiccation function.
Trehalulose
Trehalulose, disaccharide, reducing sugar, fructose + glucose, sucrose isomer in honey especially of stingless bees in Australia.
Umbelliferose
Umbelliferose, C18H32O16, trisaccharide, sweet, in Angelica, Aegopodium, reserve carbohydrate.
Verbascose
Verbascose, C30H52O26, pentasaccharide (stachyose + alpha-D-galactopyranose), sweet, in green plants storage organs, Verbascum.
Xylose
Xylose, C5H10O5, D-Xylose, wood sugar, in mist plant glycosies or polysaccharides called xylans, very sweet taste.
Arabinoxylans in cell walls, wood, and cereal grains is a combination of arabinose and xylose.
In Psyllium (Plantago ovata).
Xylose (Table).
3.1.1 Prepare sugar crystals from brown sugar
Activated carbon decolorizes and refines brown sugar solution by adsorbing coloured impurities on it.
After filtering, concentrating and cooling the white (refined) sugar crystals form.
1. Put 5 to 10 g of brown sugar in a small beaker.
Dissolve the sugar in 40 mL water by heating.
Add 0.5 to 1.0 g of activated carbon while constantly stirring.
Filter the suspension when it is still hot to obtain a colourless solution.
If the filtrate appears yellow, add a little more activated carbon, heat and filter the suspension again until the filtrate becomes colourless.
By heating, concentrate the filtrate in a small beaker on a water bath until the volume of the solution is reduced by about one quarter.
White sugar crystals separate out of the liquor after cooling it naturally.
2. Dissolve 100 g of brown sugar in 90 mL water.
Add calcium hydroxide solution until the solution turns red litmus blue.
Filter the solution then heat the filtrate with absorbent charcoal while it is still hot.
Evaporate at reduced pressure at 50 to 65 oC.
Put the syrup in a refrigerator for several days to form crystals.
3.1.2 Prepare sugar crystals from sugar cane juice
In production of cane sugar, the solution is clarified by adsorbing impurities on bone char, a type of carbon made by heating bones in the absence of air.
Add calcium hydroxide to sugar cane juice or sugar beet juice until red litmus turns blue.
Leave it to stand overnight.
Filter by suction.
Evaporate in reduced pressure at 50 to 65 oC until it becomes a brown syrup that is so viscous that it scarcely flows.
Put the syrup in a refrigerator for several days to form crystals.
Use a centrifuge to separate crystals from the liquor.
3.1.3 Sucrose octoacetate
Sucrose octoacetate, C28H38O19, acetylated derivative of sucrose, , is used as a bitterant.
It is used as a harmless aversive agent for methanol, (methylated spirits), to make an undrinkable denatured spirit, because methanol caused blindness in alcoholics who are determined to drink it.
3.1.4 Sucrose with borax
A colour reaction.
Sugar has a similar reaction to glycerine on borax and phenolphthalein, but different strengths of solutions are needed.
Dissolve half a 2 mL of borax in a test-tube nearly full of water and add one or two drops of phenolphthalein to obtain a rose red liquid.
Add solid sugar, at a time, and shake the test-tube.
The colour disappears.
Heat the test-tube, the colour reappears, only to vanish again when the test-tube is cooled under the tap.
3.1.5 Sucrose with sodium hydrogen sulfate
Sodium hydrogen sulfate, NaHSO4 (sodium bisulfate)
Mix together a 2 mL of sugar and a 2 mL of powdered sodium hydrogen sulfate (sodium bisulfate).
Heat the mixture in a dry test-tube.
The contents of the test-tube swells up forming a black puffy mass of carbon.
3.1.6 Ferment sucrose with yeast
Fermentation is a chemical reaction caused by lowly forms of life, such as bacteria and moulds.
An example of this in the turning sour of milk.
Baker's yeast is a simple form of plant life, which, under suitable conditions, is able to turn sugar (and starch) into alcohol and carbon dioxide.
In bread making, it is the carbon dioxide gas that puffs up the dough and makes the bread light.
Dissolve 5 mL of sugar in a beaker of water and put the solution into a flask, fitted with a delivery tube dipping into limewater.
Add 5 mL of baker's yeast and leave the apparatus in a hot place, such as a shelf of the airing cupboard.
In an hour or two the contents of the flask begins to froth and the limewater turn milky, showing that carbon dioxide is being produced.
If the flask is left for two or three days and the contents are then filtered, alcohol can form from the filtrate by distillation.
The first few drops of the liquid formed by distillation burn with a blue flame, a characteristic of alcohol.
16.1.1 Charcoal
Charcoal, activated charcoal, charcoal powder, charcoal animal powder, charcoal blocks & drawing sticks
Animal charcoal, bone black
Charcoal: 2.1.0
Charcoal blocks: 35.3.1 (Geology)
Experiments
Absorb impurities on charcoal: 10.1.3
Prepare sugar crystals from brown sugar: 3.1.17 . (activated carbon)
Construct a beverage-can charcoal burner: 22.3.2
Separate dirt from dirty water with charcoal: 10.1.13
Separate litmus solution with charcoall: 10.1.1
Separate metals by reduction of metal oxides, charcoal blocks: 10.10.0
Prepare crystal clusters 3.1.3
Prepare crystal blossoms 3.1.2
Pyrolysis (Charcoal production)
Test substances with heated charcoal and fusion mixture: 12.11.3.8
16.1.2 Prepare gases from coal
Organic matter in a state of advanced decay, passes through the stages of compost and peat before becoming lignite (coal).
It is composed of a heterogenous mixture of compounds including phenolic radicals and acids that polymerize and are not easily separated nor analyzed.
When a substance is heated in the absence of air, its structure may be destroyed, so this process is called "destructive distillation".
Producer gas is a mixture of carbon monoxide and nitrogen.
Producer gas forms when air passes over hot coke or carbon.
2C (s) + O2 (g) + N2 --> 2CO (g) + N2 (g).
The mixture gases called coal gas forms when coal is heated strongly in the absence of air.
It is a slow process, which cannot be done in the school science laboratory.
Preparations
1. Use bituminous coal, because it contains mainly volatile hydrocarbons.
Grind the coal with a mortar and pestle.
Transfer 3-5 g of the crushed coal to the bottom of a sidearm test-tube.
Insert a stopper and clamp the sidearm test-tube with its side arm downwards and its mouth inclined down.
Connect the sidearm to a straight delivery tube inserted into a one-hole stopper in another sidearm test-tube.
Attach a glass tube to the sidearm of the second sidearm test-tube.
Heat the crushed coal in the upper test-tube with an alcohol lamp.
The heated coal decomposes to produce coal tar oil that flows down into the lower test-tube.
Hold a lighted match to the outlet of the glass tube to ignite volatile gas.
The gas burns with a light blue flame.
2. Grind bituminous coal with a mortar and pestle and put it in a Pyrex test-tube.
Fit the tube with a one-hole cork carrying a glass delivery tube.
Make a gas reservoir by punching two holes in the bottom of a large tin can.
Insert a one-hole stopper with a short glass tube in each hole.
Seal between the stopper and edge of the holes.
Use rubber tubing to connect one of the short glass tubes to the delivery tube.
Connect the other short tube to a medicine dropper tube and attach a screw type pinch clamp Hofmann clip to the rubber tubing.
Fill the can with water and invert it in a large jar of water so that it sinks to the bottom.
Heat the test-tube containing coal with a Meker burner.
The coal decomposes into several substances.
Gases from the decomposition leave the tube and fill the reservoir can by driving out the water.
As the can fills with gas, it rises in the large jar.
At first the coal gas pushes air out of the can through the second tube attached to the medicine dropper.
Close the Hofmann clip and collect the gas.
To test the gas, open the Hofmann clip and hold a lighted match to the end of the medicine dropper tube.
The gas burns until the contents of the tin can are almost exhausted.
Some volatile tar floats on the water in the can.
The remaining products of the destructive distillation, e.g. coke, remain in the test-tube.
16.1.3 Heat glucose to form carbon
Use a small piece of barley sugar or "Glucodin".
Heat the glucose on a metal lid held in a pair of pliers.
The substance melts and turns brown then black.
Note the smell of burnt sugar.
The final black residue is carbon, sugar charcoal, a very pure form of carbon.
16.1.4 Heat starch to form carbon
Heat starch on a metal lid.
Decomposition occurs and inflammable gases, which smell like burning leather, forms.
A black residue of carbon remains on the lid.
16.2.1 Carbonates
Carbonates are salts or esters of carbonic acid.
Carbonated water, carbonic acid, H2CO3, soda water: 3.9.0
Carbonates, CO32-, mineral carbonates: 35.2.18 (Geology)
Decomposition of carbonates: 3.7.3
Dilute acids with carbonates, common carbonates: 12.4.5
Heat carbonates of Cu, Mg, Na, Pb, Zn: 12.16.6
List of carbonates: 1.11
Prepare carbon dioxide, heat carbonates: 13.7.6
Prepare rayon, basic copper carbonate with ammonia solution: 3.3.8
Reactions of carbonates: 12.16.0
Tests for carbonates: 12.11.7
16.2.2 Tannins
Tannins, plant polyphenols.
1 Hydrolyzable tannins.
Ellagitannins, C44H32O27, e.g. emblicanin A, emblicanin B, punigluconin, pedunculagin.
See diagram : Ellagitannin.
Gallotannins.
Gallic acid C7H6O5, hydrolysable tannin, pseudotannin.
2 Condensed tannins.
Flavones condensed tannins, non-hydrolysable tannins, Anthoxanthins.
3 Phlorotannins.
Phloroglucinol C6H3(OH)3, a phlorotannin.
Properties:
Tannins are polyphenolic compounds with large molecular weights that have enough hydroxyl groups for effective cross linking with other compounds, astringents.
Tannins are usually divided into hydrolyzable tannins and condensed tannins.
However, the term "tannins" has been applied to any compound or plant extract that could make skin collagen impervious to degradation, i.e make leather.
Tannins are any group of yellow-brown astringent compounds from gallic acid, in bark and galls, and used to convert animal hide to leather.
The word "tannin" is based on the Celtic word for oak tree.
Tannins occur in hemlock, oak galls, mangrove, wattle, chestnut, quebracho Schinopsi, sumacs hus, canaigre, and Rumex.
Tannin, i.e tannic acid, a polyphenol, is a yellow brown compound in coffee beans, oak galls, mahogany, tea leaves, tree bark, walnuts.
It reacts with proteins in skins to form leather.
It is used as a mordant, and for inks and dyeing.
E181 Tannic acid, is not an acid, but is usually shown as C75H52O46, decagallol glucose.
It is probably a complex mixture of glucoses and esters.
Tannic acid (a polyphenol), in Caesalpinia, Rhus, does not occur in green tea or black tea.
Tannic acid is a light yellow to tan solid with a faint odour, which sinks and mixes with water.
Make a solution of tannic acid by boiling cut pieces of oak galls in water.
Tannic acid is sold as a brown powder and was used in tannic acid jelly for burns dressings.
Tea from Camellia sinensis, has a slightly bitter, astringent flavour.
Tea contains polyphenols, but tea does not contain tannic acid as previously believed.
Tannic acid is a dyeing mordant, slightly toxic if ingested.
Use tea solution to polish linoleum, windows and mirrors, remove fish smell and shine from seats of skirts or blue serge suits, deodorizes feet, dye greying white fabrics, highlight brown hair, treat sunburn
pain, with lemon treat sore throat, diarrhoea, sore eyes, burns, bleeding gums, broken finger nail, speed grass seed germination and house plant growth, with lemon deodorize stuffy rooms, clean and polish black lacquer and varnished woodwork, tenderize meat.
List of tannins:.
* Catechins: Catechins
* Chebulinic acid, C41H32O27, a gallotannin, may inhibit lipolysis, in Phyllanthus emblica fruit, in Terminalia tebula.
* Ellagic acid, C14H6O8: 16.3.6.16 from tree bark.
* Epicatechin gallate, C22H18O10, from green tea.
* Epigallocatechin, C15H14O7: Epigallocatechin from green tea.
* Epigallocatechin gallate, EPGC, C22H18O11.
Flavonols Flavonols, flavan-3-ols.
* Gallocatechin gallate, C22H18O11, from green tea
* Punicalagin, C48H28O30, from pomegranate, Trigalloylglucose.
16.4.1 Butane
Butane gas, C4H10, n-butane, gas occurs in cigarette lighters and portable gas appliances, highly flammable:
Butane gas, 93.2 MJm-3, a liquefied petroleum gas (LPG), liquefied gas, bottled gas, is liquefied butane
n-Butane, BP -0.5 oC, RD 0.60 at 0 oC, is stored as liquid under pressure in steel cylinders giving Calor gas and cigarette lighter gas.
Butane isomer is 2-methylpropane, CH3CH(CH3)CH3, formerly called "isobutane"
Packaging gases, E943a, Butane (propellant, solvent)
A mixture of butane and 2-methylpropane is used in disposable cigarette lighters
Butane is a highly flammable gas at room temperature, vapour pressure 2.4 atm.
Butane gas is stored as liquid under pressure in fire lighters.
If the lighter trigger is squeezed, the canister opens and the liquid forms a vapour.
Cigarette lighter fuel is 90% butane, isomer isobutane.
Sudden decompression in aircraft can cause butane cannisters to rupture.
| See diagram 3.32 : Collect insoluble gases over water, See 3.
| See diagram 16.1.2 : Butane isomers.
Butane gas : 16.6.4.0
Burn butane bubbles: 19.1.2.1 (Experiment)
Combustion of butane: 16.6.4.2
Density of gases, Butane (Table)
See diagram 16.1.2 Butane isomers
See diagram 16.1.1h Octane ratings (Table)
Prepare butane: 16.6.4.1 (Experiment)
Butane compounds
cis-butane-1,4-dioic acid, maleic acid
cis-butane-1,4-dioic anhydride, maleic anhydride
trans-butane-1,4-dioic acid, fumaric acid
12.1.11 Butyl chloride rainbow reactions
Butyl is an alkyl radical —C4H9, from butane, e.g."butyl acetate", C6H12O2, CH3COO(CH2)3CH3
Butyl chloride may be n-Butyl chloride (butan-1-chloride), 1-chlorobutane, C4H9Cl, sec-Butyl chloride (butan-2-chloride)
Isobutyl chloride (1-chloro-2-methylpropane), tert-Butyl chloride (2-chloro-2-methylpropane)
1. Make a pH 12 solution by adding 10 drops of 0.1 M NaOH to 100 mL water, in a 250 mL beaker.
Add universal indicator to produce a distinct colour.
Start with universal indicator.
Use a second 250 mL beaker to mix by pouring the solution back and forth between the two beakers or put a magnetic bar into the solution.
Start the stirrer motor at a fast rate.
Add 15 drops of t-butyl chloride (2-chloro-2-methylpropane) to the solution and begin mixing.
Observe any colour changes.
After 40 seconds add universal indicator and observe any colour changes.
The full range of colour changes (purple, blue, cyan, emerald-green, lime-green, yellow, orange, orange-red, take about two minutes.
The changes in the middle are more rapid than the changes at either extreme.
Use different indicators to show different colour changes and different induction times.
2. Prepare two solutions, 0.1 M 2-chloro-2 methylpropane (t-butyl chloride) in ethanol (1 g per 100 mL) and 0.01 M sodium hydroxide.
Put 5 mL 0.1 M C4H9Cl in a test-tube.
In another test-tube put 5 mL 0.1 M NaOH, 10 mL water and two drops of any one of the following indicators.
Mix the solutions back and forth once and observe for the colour change that occurs after an induction period.
With equal volumes 0.01 M sodium hydroxide and 0.1 M C4H9Cl the colour changes with universal indicator were:
| Purple to blue (on mixing) | blue to green (after 12 seconds) | green to yellow (after 15 seconds) | yellow to orange (after 25 seconds total) |
Cooling the solutions greatly slows the reaction, increasing the induction period, e.g. with iced water, the methyl red change took more than 50 seconds.
16.4.2 Carbon disulfide
Carbon disulfide, , CS2, is toxic by all routes and it is Not permitted in schools.
Pure carbon disulfide, colourless liquid, pleasant odour like chloroform.
Laboratory carbon disulfide, colourless-yellow liquid, strong, disagreeable cabbage-like odour, highly refractive, slightly soluble in water
It is miscible with anhydrous methanol, ethanol, ether, benzene, chloroform, carbon tetrachloride, and oils; fat-solvent properties: highly flammable
It has a very low flash point, forms explosive mixtures with air, catches fire very easily, dangerous when exposed to heat, flame, sparks, or friction.
Carbon disulfide reacts with strong oxidizers, sodium, potassium and zinc azides; rust; halogens; and amines.
It reacts violently with chlorine, nitric oxide, and zinc.
It burns in air with blue flame to form carbon dioxide and sulfur dioxide.
Carbon disulfide is used in manufacture of regenerated cellulose rayon by the viscose process and cellophane.
It was used as grain fumigant in USA until 1985. See:
Experiment
Prepare rayon, copper (II), sulfate with ammonia solution "regenerated fibre", "artificial silk": 3.3.8
16.4.3 Carbon monoxide
Carbon monoxide, C≡O, (note triple bond), (carbonyl, CO), monodentate, ligand, Toxic by inhalation.
Do not prepare in the laboratory!
Carbon monoxide, Solution < 3%, Not hazardous.
Catalytic conversion of nitric oxide: 3.44.1
Carbon monoxide, danger of vehicle exhausts, tailpipe gases: 18.6.10
Commonly occurring air pollutants, safe air and clean air: 18.6.0.1 (See: carbon monoxide).
Decomposition of oxalic acid: 3.7.14
Methanoic acid (formic acid) ionization reaction: 16.2.7
Nicotine, tobacco smoking and chewing: 5.5.21
Oxides, acidic oxides and basic oxides: 12.13.4
Phosphorus pentoxide: With formic acid forms highly toxic carbon monoxide gas.
Potassium ferrocyanide: Heating with concentrated sulfuric acid forms carbon monoxide gas.
Reaction of carbon with steam, water gas: 12.15.5
Tests for substances with hot concentrated sulfuric acid: 12.11.3.6 (See: 8 and 9).
Carbon monoxide
Carbon monoxide, CO, carbon oxide, carbonic oxide (carbonyl, CO), monodentate ligand
Be careful! Do NOT make carbon monoxide.
See 18.6.3 : Danger of vehicle exhausts, tailpipe gases
1. Toxicity and air pollution
Carbon monoxide is very toxic.
It can cause unconsciousness due to combination of the gas with haemoglobin in the blood, and prevents the blood from acting as an oxygen carrier.
Death can occur from carbon monoxide inhalation.
Do not prepare carbon monoxide in an open room.
Carbon monoxide is particularly dangerous, because it is a colourless, odourless and tasteless gas.
It kills more people than any other gas.
The gas can form accidentally by leaving a car engine running in a closed garage, or by burning a gas fire with restricted ventilation.
When carbon or carbon compounds burn in a limited supply of air, the reaction forms carbon monoxide.
It is very flammable and forms explosive mixtures with air.
It forms when carbon in fuels (petrol, wood, coal, natural gas) is not burned completely.
It is soluble in some organic solvents, such as ethyl acetate, chloroform and acetic acid.
It forms toxic and flammable compounds when exposed to finely dispersed metal powders.
It may react vigorously with oxygen, acetylene, chlorine, fluorine and nitrous oxide.
2C (s) + O2 (g)--> 2CO (g)
carbon + oxygen gas--> carbon monoxide
2. Carbon monoxide is insoluble in water, but it is absorbed by potassium hydroxide solution.
Carbon monoxide burns with a pale blue flame forming carbon dioxide.
2CO (g) + O2 (g)--> 2CO2 (g)
3. Carbon monoxide can act as a reducing agent and is the main reducing agent in a blast furnace.
At high temperatures, carbon monoxide reduces the oxides of copper, lead and iron to the metal.
Metal oxides are reduced by passing carbon monoxide over the heated oxide.
CuO (s) + CO (g)--> Cu (s) + CO2 (g)
Fe2O3 (s) + 3CO (g)--> 2Fe (s) + 3CO2 (g)
4. Use fume cupboard to reduce metallic oxides to the metal by passing carbon monoxide over the heated oxide.
16.3.1 Alkanes CnH2n+2, paraffins
Alkanes (paraffins): aliphatic hydrocarbons with only single bonds, i.e. just C-C, C-H single bonds
Alkanes, cyclohexane, heptane, hexane, liquefied petroleum gas (LPG), octane, pentane, petroleum spirit
Alkanes: methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane
The first 10 unbranched alkanes and molecular formula: methane CH4, ethane C2H6, propane CH3H8, butane CH4H10, pentane CH5H12, hexane CH6H14, heptane CH7H16, octane CH8H18, nonane CH9H20, decane CH10H22
Alkanes burn in oxygen to give carbon dioxide and water.
Candle wax is a mixture of different alkanes that are solid at room temperature.
Alkanes are usually associated with natural petroleum deposits and can be distilled from petroleum.
1. Alkanes (paraffins) are saturated hydrocarbons, i.e. all single bonds between C atoms, have formula CnH2n +2 and names end in "ane".
The names of unbranched alkanes come from the number of carbon atoms.
The name of branched alkanes come from the longest chain of carbon atoms.
The hydrocarbon branches, alkyl groups, symbol R, are formed by removing one hydrogen atom from the alkane and named by changing the "ane" to "yl", e.g. methane, CH4 to methyl, CH3 - , also "Me".
The carbon atoms of the longest continuous name are numbered starting at the end of the chain closest to the first branch, e.g. an eight carbon chain with an ethyl group attached to carbon 5 and a methyl group attached to carbon 3 and carbon 4 is called 5-ethyl-3, 4-dimethyloctane.
Saturated hydrocarbons, e.g. hexane C6H14, all carbons have either four or three hydrogens bonded to them and no double bonds, triple bonds or rings, react in almost the same way.
Formation of alkanes:
* Hydrogenation of alkenes --> alkanes
CH2=CH2 + H2 --> CH3-CH3 (Pt catalyst)
ethylene + hydrogen --> ethane
CH3CH=CHCH3 + H2 --> CH3CH2CH2CH3 (Pt catalyst)
* Decarboxylation (remove CO2) from molecules that have -COOH group
RCOONa + NaOH --> R-H + Na2CO3 (dry distillation with soda lime)
CH3COONa + NaOH --> CH4 + Na2CO3
16.4.4 Ethane, C2H6
Ethane C2H6 | CH3.CH3 | H3C.CH3
See diagram 16.1.1 : Ethane
Ethane is a colourless and odourless gas, which has properties similar to methane.
CFCs, chlorofluorocarbons, "Freons": 12.19.5.0
Density of gases, Ethane (Table)
13.3.0: Prepare gases with gas generation apparatus
16.6.1.1 Prepare ethane gas
This experiment was called the "wet asbestos method", because asbestos wool was used to soak up methyl iodide in the test-tube.
However, asbestos wool is not allowed in schools.
Pour 2 cm methyl iodide in a test-tube.
Add 5 g of copper turnings and push it down firmly with a spatula.
Set up the apparatus and heat the mixture.
2CH3I + 2Cu --> C2H6 + Cu2I2
16.4.5 Ethene
Ethene (ethylene) C2H4, CH2.CH2, H2C=CH2, the simplest alkene, highly flammable, asphyxiating gas, can cause anaesthesia
Ethene gas is a plant growth substance produced in wounded, diseased and ripening tissues, reacting with auxins to induce fruit ripening and abscission of leaves or diseased parts
Ethylene is used to ripen stored fruit artificially, e.g. bananas: 14.0 Banana ripening.
Alumina as a catalyst in the cracking process: 12.1.10
Ethylene gas, CH2, abscission: 9.1.7.3
Alkenes CnH2n, olefins: 16.1.1.2.0
Alumina as a catalyst in the cracking process: 12.1.10
Auxins: 9.1.7.1 (2.)
Breakdown ethanol to ethene: 3.96
Burn ethylene in chlorine: 12.4.8.7
Chemical sources of polymer materials, ethylene (LD), ethylene (LLD), ethylene (HD)
Density of gases, ethene: 12.4.0 (Gas, Molecular weight, Density), (Table 1)
Ethylene chlorohydrin C2H5ClO, break yam dormancy
16.4.5.1 Ethylene, absorption by oxidation with sodium permanganate
Ethylene absorption by oxidation with sodium permanganate
Prepare preserving agents for cut flowers: 19.6.5
Prepare ethene (ethylene), C2H4: 16.1.1.2.1
Ethylene compounds
Acrylamide: 16.1.5.6.1
Chelates
Cracking
EDTA, Ethylenediaminetetraacetic acid: 4.0
EDTA, Ethylenediaminetetraacetic acid disodium salt, EDTA: 9.10.0
EDTA, Mineral deficiency experiment, hydroponics: 9.9.18.5
EDTA, synthetic chelating agent: 16.4.4 (3.)
EDTA, Test for water hardness, Calmagite indicator: 12.3.5
EDTA, Tests for water hardness, Eriochrome Black T indicator: 12.3.6
Ethephon phosphonate, Plant growth regulators: 9.88.1
Ethylene chlorohydrin Yam project
Ethylene absorption by oxidation with sodium permanganate: 16.4.5.1
Ethylene aldehyde: Acrolein
,Ethylene aldehyde, Tests for glycerine
Ethylene bisthiocarbamate, Mancozeb: 16.6.13
Ethylene bromide, Cassava project: 17. (9.)
Ethylene chlorohydrin, C2H5ClO, (2-chloroethyl alcohol), (2-chloroethanol),  highly toxic
Ethylene dibromide, Tests for unsaturated hydrocarbons, bromine water tests for unsaturation: 9.3.20
Ethylene dibromide, 1,2-Dibromoethane: 12.18.16
Ethylene dibromide: 4.13.9.2 Fumigants
Ethylene dibromide: Dibromo
Ethylene dichloride (1.2-dichloroethane, Freon 150), C2H4Cl2, ClH2C-CH2Cl, toxic, highly flammable
Ethylene dichloride, 1,2-dichloethane, Solution < 1%, Not hazardous
Ethanediol C2H6O2, anti-freeze
16.4.6 Ethyne
Prepare acetylene gas, ethyne, C2H2: 16.4.6.1
Tests for acetylene, ethyne: 16.4.6.2
Oxyacetylene welding: 34.12
Acetylene, ethyne
Acetylene, C2H2, ethyne, Use acetylene in a fume cupboard or use very small quantities in a well-ventilated area.
Use eye and skin protection to avoid splashes.
Mixtures of acetylene and air may be dangerously explosive.
Explosive acetylides form when acetylene reacts with silver or copper (I) salts.
Formerly, bicycle "carbide lamps" used calcium carbide + water ---> acetylene + calcium hydroxide.
However, the calcium carbide used to decompose in moist air to form the unpleasant odour of acetylene.
The gas has a foul smell, because of the presence of traces of phosphorus hydrides.
This decomposition could be lessened by pouring petroleum over the calcium carbide to exclude air and moisture.
Acetylene forms highly explosive mixtures with air, but is otherwise not toxic.
As prepared from the reaction of calcium carbide with water, it usually has an evil smell, because of the presence of small amounts of phoshpines, R3P.
Do not inhale the impure gas.
Handle acetylene cylinders with care.
Unplanned release of a large quantity of acetylene may result in a serious fire or explosion.
In acetylene cylinders, acetylene is dissolved in acetone supported on a porous diatomaceous earth base.
The pressure inside an acetylene cylinder is therefore lower than in other cylinders that contain compressed gases, e.g nitrogen.
16.4.6.1 Prepare acetylene
CaC2 + 2H2O → Ca(OH)2 + C2H2↑ The main hazard with calcium carbide is the ignition of air / acetylene mixtures.
A violent explosion may occur, depending on the proportions of air and acetylene.
Acetylene, when undiluted with air, burns with a smoky flame.
Before igniting acetylene, be sure that it is not mixed with air.
Purchased calcium carbide usually contains sulfur and phosphorus compounds that react with water to form strongly smelling gaseous impurities that act as a convenient indicator for the presence of acetylene.
1. In a fume cupboard, put a 2 g lump of calcium carbide in a 250 mL beaker.
Add water drop-by-drop.
Calcium carbide reacts vigorously with water forming acetylene gas (ethyne) and releasing a considerable amount of heat.
Ignite the resulting bubbles of acetylene.
2. On a metal tray or shallow container in a fume cupboard, add water drop-by-drop to one lump of calcium carbide.
The water will hiss and the gas will be produced.
The lump will fall to pieces to form a powder of calcium hydroxide.
Do not attempt to ignite the acetylene produced.
3. Put a < 5 g lump of solid calcium carbide in 500 mL of water and ignite the ethyne produced.
Do this experiment outside, with the observers at least 2 metres away.
4. Formerly, bicycle "carbide lamps" used the following reaction.
Put sand in a dry test-tube and add pieces or lumps (not powder) of calcium dicarbide (calcium carbide).
Add water drop by drop.
Collect the gas over water.
CaC2 + 2H2O --> C2H2 + Ca(OH)2.
calcium dicarbide + water --> ethyne (acetylene) + calcium hydroxide.
5. Collect acetylene from oxy-acetylene equipment.
16.4.6.2 Tests for acetylene
Light the gas in the test-tube with a glowing splint.
The gas burns with a smoky flame.
16.4.7 Heptane
Heptane, C7H16, BP 98 oC, RD 0.68, nine isomers, normal heptane has similar properties to normal hexane.
Heptane, n-heptane, heptane fraction, toxic by all routes, Highly flammable: 16.6.7.0
Heptane may be used as an alternative to hexane Heptane, octane number: See diagram 16.1.1h
16.4.8 Hexane
Hexane, C6H14, CH3(CH2)4CH3, n-hexane, normal hexane, hexane fraction, toxic by all routes, Highly flammable
Hexane, BP 68.7 oC, RD 0.66, exists as five compounds with same formula, normal hexane, n-hexane, in petrol and petroleum ether solvent, colourless liquid ethereal odour.
"Shellite" (Australia) is 60% hexane and 40% heptane.
Stem name: hex-
Hexane, octane number: See diagram 16.1.1h
Hexane, Solution < 5%, Not hazardous
Hexane, Cleaning agents, solvents: 2.20.4
Hexane-1,6-diamine, C6H16N2, 1,6-Hexanediamine
Adipic acid (hexanedioic acid)
Alkanes CnH2n+2, paraffins (hexane): 16.4.1.1
Cyclohexane
Flammable: 7.9.22 (See: 6.)
Diaminohexane
Hexanedioicacid adipic acid, C6H10O4 or HOOC(CH2)4COOH
Hexanedioyl dichloride, C6H8Cl2O2, adipoyl chloride, adipoyl dichloride, toxic by all routes
Lactams (-NH(CO-), caprolactam: 16.3.4.0.3
Prepare nylon polymer: 3.4.7
Reactions of bromine water (bromine solution): 12.19.9.2 (See: 6.)
Size of carbon atom in stearic acid molecule: 11.3.4
Tests for iodides (hexane): 12.11.12 (See: 3.)
Tests for unsaturated hydrocarbons: 9.3.20
16.4.9 Octane
See diagram 16.1.1h : Octane ratings.
Octane, C8H18, CH3(CH2)6CH3, BP 126 oC, RD 0.702 at 20 oC, exists as eighteen compounds, in petroleum.
Octane, C8H18, n-octane, colourless, normal octane, Harmful, stable, but highly flammable
Isomeric with iso-octane, 2,2,4-trimethylpentane (CH3)3CCH2CH(CH3)2.
16.7.9 Octane C8H18, Octane number
iso-Octane
n-Octane
Cracking
Spark plug, pre-ignition: 32.5.5.10
16.4.10 Pentane
Pentane, n-pentane, C5H12, CH3(CH2)3CH3, colourless liquid, highly flammable, so use other less volatile alkanes
Pentane, BP 36.3 oC, RD 0.63, is made by distillation of petroleum.
Pentane : 16.6.5.0
Pentane: See diagram 16.1.1h octane number
Pentanedioic acid, glutaric acid (not glutamic acid!), COOH(CH2)3COOH
16.2.8 Pentanoic acid (valeric acid)
16.4.11 Propane
Propane, C3H8, colourless liquefied petroleum gas, a bottled gas, BP -42.2 oC, catalytic cracking forms propylene, propellant, aerator, fuel for gas barbecue and blow torch
Propane gas, a bottled gas, a liquefied petroleum gas (LPG)
propyl (C3H7-, Stem name: prop-
Propane: 16.6.2.0
Propane: See diagram: 16.1.1h octane number
Density propane (Table)
Packaging gases, propellants, food additives: 19.4.22 propane-1,2,3-triol, glycerin, glycerine
Relative mass of gases, propane: 16.4.11.1
LPG Liquefied Petroleum Gas
16.4.11.1 Relative molecular mass of gases
See diagram 13.1.5 : Relative molecular mass of gases
12.3.2 : Saturated vapour pressure over water
The relative molecular mass, M, of a compound is the ratio of the average mass of molecules of the substance to 1 / 12 of the mass of one atom of C-12.
Number of moles = volume in litres / 22.4 litres / mol. At STP, 1 mol of most gases occupies 22.4 L at STP.
At 25 oC, 1 mol of most gases occupies 24.45 L.
Weigh a gas container.
Collect 1 litre of gas in an inverted measuring cylinder over water.
The levels of water inside and outside the measuring cylinder must be the same.
Weigh the gas container again.
Calculate the loss in weight (about 2 g).
Note the temperature and atmospheric pressure.
For propane, if loss in weight of gas container = 1.8 g, 1.8 × 24.45 = 44 = relative molecular mass of propane.
Use other sources of gas, e.g. a cigarette lighter.
Hold it under water below the measuring cylinder with the valve kept open with a rubber band.
16.4.12, Trichloroethane
Trichloroethane, CH3CCl3, 1,1,1-trichloroethane, methyl chloroform, Toxic if ingested, do not inhale vapour
Trichloroethane 1,1,1-trichloroethane), Solution < 25%, Not hazardous
ACS reagent (may contain 0.05% low alkyl epoxide as stabilizer), "Chlorothene", (E512), methyl chloroform, grease solvent
It is sa afer alternative to tetrachloromethane (carbon tetrachloride, CCl4).
It was the solvent in "white-out" correction fluids, but banned in many school systems, because of "sniffing".
Ozone-depleting chemical being phased out of use.
Mixed with active metals, e.g. Na, Mg, Al, forms metal chloride and carbon in highly exothermic reaction.
Substitute for non-chlorinating solvents, e.g. acetone or ethanol.
16.4.13, Trichloromethane, Chloroform
Do NOT store, or use trichloromethane in school science laboratories.
Chloroform, CHCl3, trichloromethane, colourless liquid, pleasant odour, sweetish taste.
It was formerly used as an inhaled anesthetic during surgery, but is now used as a solvent and fumigant.
Trichloromethane, CHCl3, chloroform, methane trichloride, TCM, Freon 20, Refrigerant R20, Toxic by all routes, irritant, possibly carcinogenic
Not permitted in schools, harmful, local purchase, vapour in flame may form poisonous gases, BP. 61 oC, Store in a dark, cool place.
Experiments
Methane with chlorine: 16.5.1.3 (Dangerous experiment)
Prepare trichloromethane, (chloroform): 16.1.8
Reaction of ethyl alcohol with bleaching powder: 16.1.14.2 (Dangerous experiment)
16.5.1 Sugars
Sugars are simple carbohydrates, one or more monosaccharide units, soluble in water, optically active, sweet to taste and fermentable.
However, the term "sugar" generally refers to monosaccharides and lower oligosaccharides.
"Reducing sugars" reduce copper (II) to copper (I) salts in Fehling's solution or other test solutions, show presence of aldehyde group.
Monosaccharides have a straight chain form or ring form, cannot be split into smaller molecules using dilute acids, cannot be hydrolysed to simpler compounds.
Table 16.3.1.3 Aldose sugars and ketose sugars
9.142 Fehling's test.
Monosaccharides
Monosaccharides, D and L sugars
Pentosans
9.3.6 Tests for breakdown of starch to sugars
9.3.17 Tests sugars
Sugars (Experiments)
16.5.2 Monosaccharides
Monosaccharides, Cx(H2O)y, where x = 1 or 2 or 3, contain a single sugar unit, e.g glucose, fructose.
So they cannot be hydrolysed to simpler sugars.
See diagram 16.3.1.3x : Glucose and fructose, straight chain forms.
List of monosaccharides
| Apiose | Arabinose | Deoxyribose | Digitalose | Fructose | Galactose | Galacturonic acid | Glucosamine | Glucose | Glucuronic acid | Hamamelose | Mannose | Rhamnose | Ribose | Ribulose | Sorbose | Xylose |.
| See diagram 16.3.1.3a : Aldose: D-glyceraldehyde, L-glyceraldehyde, Ketose: dihydroxyacetone.
| See diagram 16.3.1.3b : Aldose sugar: Glucose.
| See diagram 16.3.1.4B : Aldose sugar: Galactose.
| See diagram 16.3.1.3d : Ketose sugar: Fructose.
| See diagram 16.3.2.8.2 : Aldose sugar: Ribose, deoxyribose, nucleotide.
16.3.1.0 Aliphatic compounds
Arabinose, Deoxyribose, Digitalose, Fructose, Galactose, Glucose, Glucuonic acid, Mannose, Rhamnose, Ribose, Ribulose, Sorbose, Xylose
Classification: of monosaccharides.
1. Classification by number of carbon atoms.
Triose, 3 carbon atoms, C3H6O3, dihydroxyacetone, glyceraldehyde.
Tetrose, 4 carbon atoms, C4H8O4, e.g. erythrose, threose, erythrulose.
Pentose, 5 carbon atoms, C5H10O5, e.g. arabinose, lyxose, ribose, xylulose.
Hexose, 6 carbon atoms, C6H12O6, e.g. allose, altrose, glucose, mannose, gulose, idose, galactose, talose.
2. Classification by whether aldose or ketose.
Aldose
An aldose contains the aldehyde group (-CHO), i.e a carbonyl, group, C=O, with a hydrogen atom attached to the carbon atom, e.g glucose.
A monosaccharide bonded to an aldehyde chain, Cn(H2O)n, e.g. glyceraldehyde, CHOCHOHCH2OH, the simplest aldose.
An aldose sugar is also an aldehyde which contains one aldehyde group per molecule.
Ketose
A ketose contains the ketone group (-CO-), at C2, monosaccharide sugar containing a ketone group or compound derived from a ketone.
A ketone group is a carbonyl group, C=O, with two single bonds to other carbon atoms.
A ketose sugar contains one ketone group per molecule, e.g fructose, CH2OHCHOHCHOHCHOHC=OCH2OH.
Ketose sugars include:
* Dihydroxyacetone
* Xyulose, C5H10O5, pentose, not used as a sweetener.
Sold as: D-Xylulose, D-threo-Pentulose, faint yellow syrup.
Aldoses and ketoses
C Atoms.
 Aldose sugars contain an aldehyde group, R-(CHO).
 Ketose sugars contain a ketone group, R1R2>(C=O).
3 C triose.
 Glyceraldehyde |.
 Dihydroxyacetone |.
4 C tetrose.
 Erythrose | Threose.
|.
 Erythrulose |.
5 C pentose.
 Arabinose | Ribose | Xylose | Ribulose |
6 C hexose.
 Galactose | Glucose | Mannose | Fructose | Sorbose |.
.
16.5.3 Monosaccharides, D-sugars and L-sugars
Left-handed and right-handed structural forms, D-sugars and L-sugars
See diagram 16.3.1.3a : Monosaccharides, D-sugar and L-sugar
The Fischer projection formula, Emil Fischer (1852 - 1919), allows 3-dimensional sugar and amino acid molecules to be represented by 2-dimensional diagrams.
Horizontal lines show groups projecting above the plane of the page towards you.
Vertical lines show groups projecting below the plane of the page away from you.
So D-glyceraldehyde has the hydroxyl group on C2 on the right and L-glyceraldehyde has the hydroxyl group on C2 on the left,
(Latin: dextro = right, laevo = left).
In other carbohydrates, if the C atom farthest from the aldehyde or ketone group has the same arrangement as D-glyceraldehyde, hydroxyl on the right of C2,
then the compound is a D-sugar.
Similarly, if this "remote carbon atom" has the same arrangement as L-glyceraldehyde, the compound is an L-sugar.
However, monosaccharides exist mainly as cyclic forms, not the aldo-forms or keto-forms.
16.5.4 Disaccharides
Disaccharides have 2 monosaccharide units.
Hydrolysis of disaccharides with acids or enzymes gives two molecules of monosaccharide.
In a disaccharide, the two monosaccharide units are joined via the oxygen atom, a glycosidic linkage.
Disaccharides contain two sugar units:
maltose, malt sugar = (glucose + glucose): See diagram 16.3.1.4a : Maltose molecule
lactose, milk sugar = (glucose + galactose): See diagram 16.3.1.4b : Lactose molecule
sucrose, table sugar = (glucose + fructose): See diagram 16.3.1.4c : Sucrose molecule
16.5.5 Haworth projection
See diagram 16.3.2.9 : Fischer projection and Haworth projection of glucose
The cyclic structure of monosaccharides is shown by a "Haworth projection", invented by W N Haworth, 1813-1950, England.
The oxygen atom is at the upper right and the carbon atoms are arranged clockwise with C1 at the far right.
The hydroxyl groups on the right in the Fischer projection are down in the Haworth projection So the hydroxyl groups on the left in the Fischer projection are up in the Haworth projection.
The terminal -CH2OH group is up in the Haworth projection for D-sugars, and down for L-sugars.
D-glucose can have α-or β-forms, depending on the position of the hydroxyl group attached to C1, down in the α-form and up in the β-form.
Most monosaccharides have a ring cycle of six atoms, one oxygen atom and five carbon atoms, called the pyranose form.
A ring cycle of 5 atoms, one oxygen atom and four carbon atoms is called a furanose form.
So D-fructose can exist as α-D-fructofuranose, -OH on C2 is down, and β-D-fructofuranose, -OH on C2 is up.
Glucose, Sold as: "D-(+)-Glucose, dextrose".
Fructose, D form, but laevorotatory, so "L-fructose", Sold as: "D-(-)-Fructose, D-Levulose, Fruit sugar".
16.5.6 Oligosaccharides
Usually have 3 to 10 monosaccharide units, only sucrose occurs in all plants, raffinose and stachyose occur in most legume seeds.
Ajugose hexasaccharide
Cellobiose, disaccharide
Gentianose trisaccharide
Gentiobiose disaccharide
Inulin C22
Lactose disaccharide
Lactulose, disaccharide
Laminaribiose disaccharide
Lepidimoide disaccharide
Lychnose tetrasaccharide
Maltose disaccharide
Melezitose trisaccharide
Raffinose trisaccharide
Stachyose tetrasaccharide
Sucrose disaccharide
Trehalose disaccharide
Trehalulose disaccharide
Umbelliferose trisaccharide
Verbascose pentasaccharide
16.5.7 Polysaccharides
Polysaccharides, e.g. amylose, usually have more than ten monosaccharide units linked by glycosidic bonds, between C1 on one sugar and C4 on other sugar by removal of water molecule, i.e a condensation reaction.
Cellulose (Experiments)
Glycogen (Experiments)
Pentosans
Starch (Experiments)
16.5.8 Prepare rock candy crystals
Cut a length of string longer than the depth of a tall jar and wind the end around a pencil.
Attach a paper clip to the bottom of the string so that it hangs straight down 2 cm from the bottom of the tall jar.
Wet the string and roll it in granulated sugar and leave it to dry.
Slowly add one cup of sugar to three cups of water in a pan while stirring.
Heat the solution until it boils.
Be careful! The boiling point of a sugar solution < 100 oC.
Leave the sugar syrup to cool, then pour it into the tall jar.
Place the pencil with attached sugared string across the top of the tall jar.
In a few hour sugar crystals will start to form and will continue forming for days.
16.5.9 Sugar acids
Sugar acids, acidic sugars, monosaccharides with a carboxyl group, [C(=O)OH], at one end of the chain or at both ends of the chain.
Sugar acids occur when a carbonyl group, C=O, or a hydroxyl group OH is oxidized to a carboxylic acid group, R–COOH.
Classes of sugar acids include:.
1. Aldonic acids: | Ascorbic acid | Gluconic acid | Glyceric acid, Xylonic acid.
2. Ulosonic acids: Neuraminic acid.
3. Uronic acids: | Glucuronic acid | Galacturonic acid.
4. Aldaric acids: | Tartaric acid |.
16.6.1 Tests for alcohols
Tests for primary, secondary and tertiary aliphatic alcohols
To one drop of each alcohol in three test-tubes, add saturated potassium manganate (VII) solution drop by drop with shaking.
If decolorization occurs, continue adding drops until pink coloration persists, as shown by spot testing on filter paper.
Add one drop of concentrated sulfuric acid and resume adding potassium manganate (VII) drop by drop.
No decolorization occurs with tertiary alcohols.
The colour eventually fades with secondary alcohols, but persists with primary alcohols.
16.6.2 Tests for unsaturated alkanes
1. Ignition tests for unsaturation
Ignite a substance in an evaporating basin and observe the smoke over the flame.
The darker or more sooty the smoke, the more unsaturated, e.g. aromatic compound.
If clear over a luminous flame, the compound is saturated, e.g. n-hexane.
2. Bromine tests for unsaturation
Bromine is a coloured compound, but it reacts with double bonds or triple bonds to form a colourless brominated compound.
alkene or alkyne + bromine water, yellowish colour disappears
3. Decolorization of bromine water
Hexane does not decolorize bromine water.
Aromatic compounds also do not decolorize bromine water, because they are stable compounds.
4. Baeyer test for unsaturation
Change in colour of the reagent (purple permanganate to brown manganese dioxide), redox reaction
Brominate hexane and other saturated hydrocarbons with the right wavelength of light and shining it on the reaction vessel, or adding peroxide or by heating the reaction.
16.6.4.1 Prepare butane
13.3.0 : Prepare gases with gas generation apparatus
This experiment was called the "wet asbestos method", because asbestos wool was used to soak up the ethyl iodide in the test-tube.
However, asbestos wool is not allowed in schools.
Pour 2 cm ethyl iodide in a test-tube.
Add 5 g of copper turnings and push it down firmly with a spatula.
Set up the gas generation apparatus and heat the mixture.
2C2H5I + 2Cu --> C4H10 + Cu2I2
16.6.4.2 Combustion of butane
Butane / Oxygen combustion
2C4H10 + 13O2 --> 8CO2 + 10H2O + energy
16.7.15 Prepare glucose with starch
Boil a 2 mL of starch with half a test-tube of dilute sulfuric acid or sodium hydrogen sulfate (sodium bisulfate), solution for two minutes.
Then pour off drops of the liquid into another test-tube, cool it under the tap, and test it by adding a drop of iodine solution.
The liquid turns red.
The starch has been changed into dextrin, a substance, which, like starch, is given the same formula.
In this case, however, z (number of amylose units) is supposed to be a much smaller number than for starch.
Continue boiling the remainder of the liquid for another three minutes to convert the dextrin into glucose.
To show that glucose has been formed, cool the liquid and neutralize it in an evaporating basin with dilute sodium carbonate or sodium hydroxide solution, (test with litmus paper).
Add 2 cm of the neutralized solution to a precipitate of copper hydroxide made from solutions of copper sulfate and sodium hydroxide.
If the test-tube is warmed, a yellow precipitate, which turns red, of cuprous oxide forms.
Dry heat breaks down starch to dextrins ("pyrodextrins") to give the brown colour of toast.
16.7.18 Prepare glucose with sugar
Boil a 2 mL of sugar in a test-tube with 2 cm of dilute sulfuric acid or sodium hydrogen sulfate (sodium bisulfate), solution.
Keep the liquid boiling for two or three minutes and then cool the test-tube under the tap.
To show that the solution now contains glucose, first neutralize the remaining acid with sodium carbonate or dilute sodium hydroxide solution, (test with litmus paper).
Then apply the copper hydroxide test.
16.4.5.1 Ethylene absorption by oxidation with sodium permanganate
Some products use zeolite particles coated with sodium permanganate to absorb ethylene and so prolong the storage life of fruit and vegetables in a refrigerator, e.g. "Blue Apple".
The chemical reaction is as follows:.
3CH2CH2 + 2NaMnO4 + H2O --> 2MnO2 + 3CH3CHO + 2NaOH
3CH3CHO + 2NaMnO4 + H2O --> 3CH3COOH + 2MnO2 + 2NaOH
3CH3COOH + 8NaMnO4 --> 6CO2 + 8MnO2 + 8NaOH + 2H2O
Combining equations 1-3 generates:
3CH2CH2 + 12NaMnO4 --> 12MnO2 + 12NaOH + 6CO2
Even if the reaction does not go all the way through to the carbon dioxide-producing step, many of the intermediate products formed either become irreversibly bound to the media or act as reactants themselves.
Such is the case of the sodium hydroxide, NaOH, formed in equation 1 and 2.
The NaOH will react with the acetic acid formed in equation 2 to produce the sodium acetate salt, NaCOOCH3, through a simple acid-base neutralization reaction.
This is shown below.
CH3COOH + NaOH --> NaCOCH3 + H2O
Combining equations 1, 2, and 5 generates:
3CH2CH2 + 4NaMnO4 --> 3NaCOOCH3 + 4MnO2 + NaOH + H2O