School Science Lessons
2024-06-16
Chemistry, Q, R
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R |

Chemistry, Q
Contents
Quantity of chemical
Quark
Quartz, (Geology)
Quartzite, (Geology)
Quassin
Quercetin
Quicklime
Quicksand, (Geology)
Quicksilver
Quinacrine
Quinaldine red, acid-base indicator
Quinidine
Quinine
Quinol
Quinoline
Quinoline, alkaloids
Quinolizidine
Quinolizidine, alkaloids
Quinones
Quintozene
Quisqualic acid
Chemistry, R
Contents
Racemic acid
Radical
Radioactive elements
Radium, Ra
Radon, Rn
Raffinose
Rain, Calcium carbonate, (Geology)
Rain, Cations and anions, (Geology)
Rain smells, Geosmin
Rainbow reactions, Butyl chloride, (Experiments)
Rancidity of fats
Raoult's law, (vapour pressure)
Rapanone
Raphanin
Raphides
Rare earth elements, Lanthanides
Rare gases, Noble gases
Raspberry ketone
Rates of reaction
Rates of reaction, clock reactions, (Experiments)
Rates of solution, (Experiments)
Ratio and proportion, concentration, (Measurement)
Rayon, (Experiments)
Razor blades and knives:
RDX explosive, Nitrosamines
Reactions, Chemical reactions, (Experiments)
Reactions of, (Experiments)
Reagents, Solutions
Reagents, Acids and bases
Realgar mineral, As4S4, (Geology)
Rebaudioside
Rectifier, Chemical rectifier:
Recycle chemicals, (Experiments)
Red cabbage acid-base indicator
Red lead, Lead (II/IV) oxide
Red phosphorus, (Experiments)
Red phosphorus, safety matches, (Experiments)
Redox (reduction-oxidation reactions), (Experiments)
Reduce, reducing, reductants, reduction, (Experiments)
Reductants, Chemical reductants
Reduction reactions, (Experiments)
Refrigerants
Relative atomic mass, Magnesium
Re-lighting candles, (Experiment)
Renewable energy
Rennet, (Experiment)
Reproductive toxicity
Resazurin, acid-base indicator
Resazurin stain, Milk, (Experiment)
Rescinnamine, alkaloid
Reserpine, alkaloid
Residuals, Bitmen
Resins, Rosins
Resistance to pesticides, (Agriculture)
Resorcinol, (Experiments)
Restore bronze coins, Corrosion, (Experiments
Resuscitation
Resveratrol
Retene
Retinol, Retinal, Retinoic acid, Vitamin A
Retamine, alkaloid
Reticuline, alkaloid
Retort stand clamp
Retronecine, alkaloid
Reverse osmosis
Reynolds' dilatancy
Rhamnazin
Rhamnetin
Rhamnose
Rhaponticin
Rhein, cassic acid
Rhenium, Re
Rhodamine
Rhodiolin
Rhodionin
Rhodium
Rhodizonic acid, Tests for lead, (Experiments)
Rhodochrosite, (Geology)
Rhododendrol
Rhodonite, (Geology)
Rhodopin
Rhoeadine, alkaloid
Rhombifoline, alkaloid
Rhodoxanthin
Rhyolite, (Geology)
Riboflavin, (Experiments)
Ribose
Ribulose
Rice grain slope, Prepare
Ricin
Ricinine, alkaloid
Ricinoleic acid
Riddelline, alkaloid
Ridentin
Rifampin, (See: 5. CPY3A4)
Ringer solution, Prepare
Risk assessment, (Safety)
Rituximab
RNA, DNA and RNA
Roasting meat, (Cooking)
Rochelle salt, (Experiments)
Rochelle salt, Piezoelectricity, (Experiments)
Rock crystal, Quartz, (Geology)
Rock salt, Halite, (Geology)
Rocks, (Geology)
Rodenticides
RODP, Ozone depletion
Roentgenium
Rohypnol, Date rape drugs, (See: 1.)
Rosarin
Rose bengal
Rose oxide
Rose petal acid-base indicator
Rose quartz, (Geology)
Rosin
Rosmarinic acid
Rotenone, derris, (Agriculture)
Rotundine, alkaloid
RU-486, Mifepristone, "abortion drug"
Rubeanic acid, Tests for copper, (Experiment)
Rubber, Latex
Rubbing alcohol, Surgical spirit:
Rubidium, Rb
RuBisCo
Rubixanthin
Rubrofusarin
Ruby, Corundum, (Geology)
Rubrofusarin
Rusting, (Experiments
Rutaecarpine, alkaloid
Ruthenium
Rutherfordium
Rutile, (Geology)
Rutin
Quartz
Silica, SiO2, silica gel, silicon dioxide
Quartz (agate, amethyst, cornelian onyx (carnelian onyx), chalcedony, jasper, onyx, opal, rock crystal, rose quartz, smoky quartz)
Quartz, SiO2, silicon dioxide, quartz sand
Quartz
Quartz: 35.14.0, (Geology)
Expanding quartz and glass: 23.3.11
Construct molecular models (quartz): 11.2.3
Separate two solids using density differences: 3.4.10
Silica: 12.15.0
Voltage produced by mechanical stress to crystals, piezoelectricity: 32.1.2.1
Quassin
Quassin, C22H28O6, nigakilactone D, a quassinoid febrifuge, vermicide, bitter tonic
It occurs in Surinam Quassia wood, Quassia amara.
Rhodinol
Rhodinol, C10H20O, monoterpene alcohol, floral fragrance
It occurs in citronella oil, in Lemon grass
Quercetin
Quercetin, C15H10O7, [(C6-(C3-(C6], flavonol glycoside, polyphenolic flavonoid, most active of the flavonoids.
Many medicinal plants have high quercetin content, anti-inflammatory activity. by inhibiting release of histamine.
antioxidant activity, anticancer, inhibits fatty acid synthase, phytochemical,
It causes the colouring found in the skins of apples and red onions.
Quercetin may protect against heart disease and cancer, prevents damage to LDL cholesterol, antioxidant, natural anti-histamine,
anti-inflammatory, anti-cancer, but unproved addition to dietary supplements, in berries, red grapes, citrus fruit, tomato, broccoli.
Do not take quercetin if taking prescribed medicines, are pregnant or breast feeding or have liver disease.
Radium, Ra
Radium, Table of the Elements
Radium (Latin radius, spoke), alkaline earth metal
Radium is a radioactive alkaline earth metal, extracted from pitchblende, uraninite, used in cancer therapy and as a radioactive resource.
Radiation dose from entry of radioactive materials into the body: 7.2.2
Atomic number: 88, Relative atomic mass: 226.025, RD 5.0, MP = 700oC, BP. = 1140oC
Specific heat capacity: 121 J kg-1 K-1
Radon, Rn
Radon, Table of Elements
Radon, Rn (from Ra radioactive decay), in former health spas, Rn-222, Group 18, last noble gas found.
Radon is a non-metal noble colourless water-soluble gas at room temperature and pressure.
Rn2 is formed by decay of radium-226, usually under granite, where it may be a health habit to people living in granite houses.
Radon has few compounds and is used in radiotherapy.
Atomic number: 86, Relative atomic mass: (222), RD 4.4 (211 K), MP = -71oC, b.p. = -61.8oC
Specific heat capacity: 92 J kg-1 K-1
Rapanone
Rapanone, C19H30O4, a quinone, a benzoquinone, a dihydroxy-1,4-benzoquinone, antihelmintic
It occurs in Rapanea maximowiczii, in Aegiceras, in Oxalis.
Raphanin
Raphanin, Sulforaphene, sulphoraphene, C6H9NOS2, toxic, antioxidant, antibacterial, Chinese medicine. It occurs in Radish, (Raphanus raphanistrum subsp. sativus), Brassicaceae seed, and in root vegetables.
Rayon
Rayon polymer: 3.8.14
Rayon, burning test: 4.3.21, (Experiment)
Organic builders in washing powders: 12.6.11
Prepare rayon: 3.3.8, (Experiment)
Triboelectric series: 31.1.02 See: Negative polarity, 29. Rayon
Recycle
Recycle chemicals: 3.4.7 See: 1.3 Recycle
Plastics recycling code, recycling symbols: 3.4.0
Recycle copper: 12.7.8
Recycle, Recycle heavy metals safety, (Experiments)
Recycle silver: 12.16.2
Redox
Redox reactions, reduction-oxidation reactions
Redox indicators, List of redox indicators: 1.21
Redox reactions: 12.2.9
Redox reactions, Disproportionation: 17.7.16, (Experiment)
Redox titration, iron (II) sulfate: 15.2.4.5, (Experiment)
Redox reactions, Oxidation and reduction: 15.2.0, (Experiments)
Reduce
Reduce, reducing, reductants, reduction
Reduction, in a cell, oxidation at the anode and reduction occurs at the cathode.
Reduce carbon dioxide with burning Magnesium: 3.1.1
Reduce copper (I) oxide, to copper: 10.10.2, (Experiment)
Reduce copper (II) sulfate to copper sulfide: 12.1.41, (Experiment)
Reduce copper oxide with methane: 16.5.1.4, (Experiment)
Reduce iron (III) chloride with H2S: 3.43.3, (Experiment)
Reduce iron (III) chloride with SO2: 3.51.3, (Experiment)
Reduce metal oxides to metals with hydrogen gas: 3.41.7
Reduce metal oxides to metals, red lead to lead and oxygen: 10.10.1
Reduce nitrate to ammonia: 12.11.2.2
Reduce KMnO4 with hydrogen sulfide: 3.43.2
Reduce KMnO4 with sulfur dioxide: 3.51.2
Reduce red iron oxide, or rust, to iron: 10.10.3
Reducing agent, activity of metals: 12.14.0
Reducing agent, separate metals: 10.10.0
Reducing agents, Oxidizing agents and reducing agents: 15.5.0
Reducing sugars and non-reducing sugars: 9.7.0
Reductants (reducing agents): 15.2B
Reductants, List of chemical reductants: 1.22
Reduction potential, E0: 3.84.6
Reduction reactions, gain of electrons: 16.1.04
Tests for reducing sugars, Benedict's test: 9.4.0
Tests for reducing sugars, Fehling's test: 9.5.0
Resins
Resin, ion exchange resin, anion exchange resin ("Permutit"), DOWNEX AGI-X8
Melamine-formaldehyde resins, (MF): 16.2.4.2.1 Cyanamides
Resins and gums: 3.0.0
Resin Identification Code, Plastics recycling code: 3.4.0
Zeolite: 35.20.49, e.g. albite, NaAlSi3O8, (Geology)
Water softening using ion exchange resin: 12.5.16
Remove water hardness: 12.5.5
Resin, (Latin: resina, Resinum from a pine)
Resins are hard, sticky, inflammable, usually aromatic substances, insoluble in water, usually collected by incisions into fir and pine trees.
They contained organic polymers and terpenoids, e.g. alpha-pinene, beta-pinene, limonene. terpinolene, caryophyllene and resin acids.
Synthetic resins, so-called, because they at first resembled natural resins, are used to make plastics are thermosetting or thermoplastic.
Rosins, colophony, Greek pitch, are solid residues resulting from distillation of pine woods and contain diterpenes.
Rosins are used on the bows of violins and other stringed instruments.
Resveratrol
Resveratrol, C14H12O3, plant polyphenol, a stilbenoid, a glycoside, a resorcinol, (derived from a stilbene), polyphenolic phytoalexin, antioxidant,
free radical synthesis, anti-diabetic, neuroprotective, antibacterial, antifungal, lipid lowering, antioxidant, irritant, oncogene inhibitor, may be used
to treat diabetes, atherosclerosis, aging.
It occurs in seeds of transgenic oilseed rape Brassica napus, in Japanese knotweed, in red grapes skin Vita, in Polygonum, in Picea, in Pinus,
in Eucalyptus wandoo wood.
Rhein
Rhein, C15H8O6, cassic acid, rhubarb yellow, rheic acid, glucorein (rhein-8-glucoside), yellow needles or powder, cathartic.
It occurs in Rhubarb, (Rheum rhabarbarum), Polygonaceae
Rhenium, Re
Rhenium, Table of the Elements
Rhenium (Latin: Rhenus Rhine river)
Rhodamine dyes Rhodamine B, C28H31ClN2O3
Rhodamine 6G, C28H31N2O3Cl
Rhodamine 123, C21H17ClN2O3
Rhodamine B cation, Rhodamine B(1+), Rhodamine 610, C28H31N2O3+, cationic fluorescent dye, xanthene dye.
Rhodium, Rh
Rhodium, Rh, (Greek rhodos rose, from pink colour of Rh compounds), white to blue-white, hard, ductile, malleable metal
It is used in jewellery and electroplating
C28H31N2O3Cl Rhodium, Table of the Elements
Rhodium trichloride
Catalytic converter in a motor vehicle: 7.9.13.1
Rocks
Rocks and minerals: 35.1.0, (Geology)
Minerals: 35.2.0, (Geology)
Igneous rocks: 35.21.0, (Geology)
Metamorphic rocks: 35.23.0, (Geology)
Sedimentary rocks: 35.22.0, (Geology)
Riboflavin
Boiling, test the cooking water of boiled vegetables: 19.2.12
Flavonoids, (Bioflavonoids)
Diet, Bananas: 15.0
19.2.5
Lost nutrients in food: 19.2.7
Pasteurization and UHT (Ultra High temperature) of milk: 19.2.10
Poultry composition: 12.4
Regular cows milk, fresh milk, full cream milk, whole milk: 16.2.1a
Riboflavin, C17H20N4O6
Food additive E10, 1 Riboflavin, Riboflavin-5'-phosphate(vitamin B2), (In green vegetables, eggs, milk, liver), colour: orange to yellow) (in margarine)
Cassava tubers and cocoa "beans" contain riboflavin
Riboflavin, vitamin B2, Lactoflavin, Riboflavine, C17H20N4O6, (Latin flavus yellow), orange-yellow crystalline compound, a heat-stable and
water-soluble flavin is a growth promoting factor.
It is the precursor of the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), is important for tissue respiration and other metabolisms.
It is essential for healthy skin, nails, and hair.
It is used to treat vitamin b2 deficiency.
It occurs in babassu palm, burdock, pepper, (capsicum), Vitamin B2 complex vitamins in cereals, milk, eggs, malted barley, liver, kidney, heart, leafy vegetables,
whey, and especially, yeast.
It occurs freely in eye retina and urine.
E101 Riboflavin, Riboflavin-5'-phosphate, (vitamin B2), (in green vegetables, eggs, milk, liver), (colour: orange to yellow) (margarine)
Rochelle salt
Rochelle salt, KNaC4H4O6.4H2O, potassium sodium tartrate tetrahydrate, Seignette salt,
Seidlitz powder, a double salt of tartaric acid
It has a saline cooling taste as a laxative, and the large deliquescent monoclinic crystals are piezoelectric and used in "crystal" phonograph pickups.
Rochelle salt: E337
Prepare Fehling's solution: 9.142.1
Tests for proteins, biuret test: 9.6.5
Roentgenium, Rg
Roentgenium, Table of the Elements
Roentgenium (William Roentgen, 1845-1923, Germany, discovered X-rays), radioactive, transuranic (atomic number > 92)
Rose bengal
Rose bengal, C20H4Cl4I4O5, fluorochrome, histological dye, xanthene dye, organic potassium salt, related to fluorescein, C20H12O5.
The sodium salt, C20H2(Cl4I4Na2O5, is used to treat eye disorders.
It is used as a stain and to treat cancers.
Rubidium, Rb
Rubidium, Rb, (Latin rubidus red), two red lines in spectrum), silver-white, very reactive, alkali metal, in pegmatites, lepidolite and pollucite
Rubidium, Table of the Elements
Ruthenium, Ru
Ruthenium, Ru, (LatinRuthenia Russia), silver-white, rare similar to platinum, catalyst, hardens alloys
Ruthenium, Table of the Elements
Used in electrical contacts, platinum alloys, jewellery electroplating for "high-tech grey-black look"
Ruthenium (III chloride, Ruthenium (III) chloride hydrate, Ruthenium carbonyl
Rutherfordium, Rf
Rutherfordium, Table of the Elements
Rutherfordium (Earnest Rutherford, 1971-1937, New Zealand, later UK), Rutherfordium is radioactive, transuranic (atomic number > 92)
Rhaponticin
Rhaponticin, C21H24O9, rhapontin, ponticin, a stilbenoid, antifungal.
It occurs in Polygonum multiflorum, in Rheum rhubarb rhizome, in Eucalyptus.
Ridentin
Ridentin, C15H20O4, a germacrane sesquiterpenoid. cytotoxic, antitumour.
It occurs in Artemisia species.
Rutin
Rutin, C27H32O16, (quercetin rutinoside, rutoside), citrus flavonoid glycoside (C15H10O7)
It occurs in capers, olive, buckwheat, lovage, dock, dill, fennel, Ruta graveolens.
Rutin, sophorin, bioflavonoid is a yellow or greenish-yellow, needle-shaped crystals.
It occurs in many plants, fruits and vegetables, especially buckwheat, Carpobrotus, Sophora japonica, Ruta graveolens, Citrus sp. (e.g. orange, grapefruit).
Antioxidant, strengthens capillaries to prevent bruising or bleeding, anti-inflammatory, prevent atherogenesis, reduce cytotoxicity of oxidized LDL-cholesterol, utilize vitamin C to maintain collagen.
Do not take rutin if pregnant or breastfeeding.
Rutin hydrate, C27H30O16.xH2O, polyphenolic flavonoid, antioxidant, NO scavenger, free radical scavenger, protection against carcinogenesis
Rituximab
Rituximab, C6416H9874N1688O1987S44, monoclonal antibody medication, used to treat non-Hodgkin lymphoma,and other conditions, by slow injection into a vein, against the protein CD20, on the surface of immune system B cells, to trigger cell death with Cyclophosphamide C7H15Cl2N2O2P
Side effects may include easy bruising, decrease in the amount of urine or unusual tiredness
CHOP, chemotherapy for treatment of non-Hodgkin lymphoma
Cyclophosphamide, an alkylating agent
Hydroxydaunorubicin, (doxorubicin, adriamycin), an intercalating agent
Oncovin (vincristine),prevents cells from duplicating by binding to the protein tubulin
Prednisone or Prednisolone, are corticosteroids.
Component of R-CHOP21
Reactions of:
Rate of reaction, k: 17.1.9.2
Reactions of aluminium: 12.1.0
Reactions of ammonium salts and potassium salts with water: 14.2.1
Reactions of antimony: 12.2.1
Reactions of arsenic and arsenic compounds: 12.2.2.2
Reactions of aspirin (rate of reaction): 17.1.9.3
Reactions of barium compounds: 12.2.3
Reactions of benzene: 16.5.3
Reactions of bismuth compounds: 12.2.4
Reactions of bromides: 12.19.9.6
Reactions of bromine: 12.19.9.1
Reactions of bromine water (bromine solution): 12.19.9.2
Reactions of cadmium sulfate solution: 12.3.1
Reactions of calcium and calcium compounds: 12.4.1
Reactions of carbon with steam, water gas: 12.15.5
Reactions of carbonates: topic12A.html#12.16.0H">12.16.0
Reactions of chloramines in swimming pools: 18.7.23.0
Reactions of chlorine: 12.19.8
Reactions of chromium compounds, Cr: 12.5.0
Reactions of copper (I) compounds: 12.7.3
Reactions of copper (II) ions: 12.7.2
Reactions of copper (II) oxide, CuO: 12.7.1.0
Reactions of dichromates, potassium dichromate: 12.5.3
Reactions of dilute acids: 12.4.0
Reactions of dilute sulfuric acid as a acid: 12.18.5.4
Reactions of dilute sulfuric acid as a sulfate: 12.18.5.5
Reactions of hydrogen bromide, HBr: 12.19.9.4
Reactions of iodides: 12.19.6.2
Reactions of iron: 14.8.0
Reactions of iron (II) salts and iron (III) salts, Prussian blue: 14.8.1
Reactions of lead (II) salts: 12.9.1
Reactions of lead (IV) salts: 12.9.2
Reactions of lithium with water: 12.9.3
Reactions of magnesium, Mg burning or molten: 12.10.2
Reactions of magnesium compounds: 12.10.4
Reactions of magnesium oxide: 13.3.6
Reactions of magnesium with carbon dioxide, sparkler experiment: 3.77
Reactions of magnesium with water: 12.10.1
Reactions of manganese (II) salts: 12.8.1
Reactions of mercury compounds: 3.7
Reactions of: Metallic elements
Reactions of metals as reducing agents: 12.14.0
Reactions of metals with air or oxygen gas: 12.14.3
z Reactions of metals with concentrated oxidizing acids: 12.14.5
Reactions of metals with dilute acids: 12.14.4
Reactions of metals with steam: 12.15.3
Reactions of methane with chlorine: 16.5.1.3
Reactions of nickel compounds: 12.9.4
Reactions of nitrates: 12.11.2.0
Reactions of nitrites: 12.11.1
Reactions of non-metals with water: 12.15.4
Reactions of oxides: 12.13.0
Reactions of permanganate ion: 15.4.0
Reactions of phosphites: 12.13.6
Reactions of phosphorus and phosphates: 12.13.1
Reactions of potassium nitrate with water: 14.2.5
Reactions of potassium salts with water: 14.2.1
Reactions of salts: 12.10.10
Reactions of salts with water: 12.10.9
Reactions of sodium with water: 12.73.0zzz
Reactions of silver compounds: 12.16.1
Reactions of silver halides, photography: 12.19.4.0
Reactions of sodium chloride: 12.19.8.1
Reactions of sodium thiosulfate: 12.18.6.2
Reactions of strontium compounds: 12.17.1
Reactions of sulfamic acid: 12.18.6.3
Reactions of sulfuric acid: 12.18.5.0
Reactions of tin and tin compounds: 12.20.1
Reactions of urea with nitrous acid: 16.6.15
Reactions of urea: 16.5.4
12.73.0 Reactions of sodium with water
See diagram 3.73.1: Sodium with water, Sodium in water and under kerosene
Be careful! Check the safety rules in your school system before doing this dangerous experiment
2Na (s) + 2H2O (l) --> 2NaOH (aq) + H2 (g)
sodium + water --> sodium hydroxide + hydrogen gas
This is a type of redox reaction where the oxidation number of the metal increases.
1. Be careful! Check the safety rules in your school system before doing this dangerous experiment.
Use safety glasses and nitrile chemical-resistant gloves.
The reaction of sodium with water is very vigorous, because it floats on the surface, fizzes (spits), and melts, because of the exothermic reaction, to form a strong alkaline solution, pH 12-14.
2. The following experiments use a test-tube to observe the reaction of sodium with water, but some teachers use a beaker.
full of water instead to avoid problems of confining the reaction in a test-tube.
Cover the beaker with wire gauze immediately after adding the sodium.
Do not try to hold the sodium in place on the surface of the water to collect the hydrogen produced, because the gas may ignite or explode.
A safe way of demonstrating the reactions of sodium and water is to drop a very small piece of sodium into a swimming pool, and stand back!.
3. Pour a 2 cm layer of kerosene on to the surface of water in a test-tube.
Drop a 3 mm diameter side cube of sodium into the kerosene.
Adjust the layer of kerosene to be shallow enough to allow the top of the sodium to protrude above the surface.
This reaction of sodium with the water is much slower than if the sodium had been dropped directly on to the water.
You can watch the reaction through a magnifying glass held at the side, but never look down into a test-tube.
Sodium metal is lighter than water, but heavier than kerosene.
Be careful! Sodium sinks in the kerosene and floats in the water.
A small area of the sodium suddenly reacts causing a stream of hydrogen bubbles to appear.
The stream of bubbles at one side causes movement.
The irregular shape of the sodium changes to a sphere.
The sodium melts, because the reaction gives off heat.
Note any variations in light refraction and reflection below the sodium that suggests something dissolving in the water.
Slight smoke where the hot sodium is above the kerosene level suggests a slight reaction with air.
Test the gas bubbles for oxygen gas or hydrogen gas.
4. Be careful! Use a piece of sodium the size of a wheat grain or rice grain.
Do not point the open end of a test-tube containing sodium at anybody.
The experiment can be done on an overhead projector.
Put water into a Petri dish and add a few drops of phenolphthalein.
Put the Petri dish on an overhead projector.
Use forceps to take a small lump of metallic sodium stored under kerosene and wipe with a piece of filter paper.
Cut a piece of sodium the size of a red bean from the lump and then put it in the Petri dish.
Observe from the screen that the sodium grain floats on the water to melt into a small sphere, which moves very rapidly in all directions, and becoming smaller and smaller.
At last, the sodium sphere wholly disappears and the solution in the dish also changes its colour from colourless to red.
5.Be careful! Observe the reaction through the side of the test-tube.
Do not look down into the test-tube!.
Put a piece of sodium in 2 cm of water in a test-tube.
Do not point the open end of the test-tube at anybody!.
Test for hydrogen gas with a lighted splint.
Test the contents with litmus paper or phenolphthalein.
The reaction forms sodium hydroxide.
6.Be careful! Observe the reaction through the side of the test-tube.
Do not look down the test-tube!.
Pour a 3 mm layer of kerosene (paraffin oil) on to the surface of water in a test-tube.
Drop a small piece of sodium into the test-tube.
The sodium sinks in the kerosene and floats in the water.
The layer of kerosene should be shallow enough to let the top of the sodium protrude above the surface.
The reaction of sodium with water is much slower than if the sodium had been dropped directly on to the water.
A small area of the sodium suddenly reacts, which causes a stream of bubbles to appear.
The irregular shape of the sodium changes to that of a sphere.
The sodium melts, because the reaction forms heat.
Something dissolving in the water below the sodium can be seen.
Some smoke where the hot sodium is above the kerosene level suggests a reaction with air.
Test the gas bubbles for hydrogen gas.
7. Support a short length of glass tubing vertically with one end 2 cm below the surface of water.
Test the water with moist litmus paper.
Add litmus paper to the water.
The upper part of the tube must be quite dry.
Drop a piece of sodium down the tube.
Note the reaction.
Test for hydrogen gas with a lighted splint.
Test the water with litmus paper.
The water becomes alkaline.
2Na (s) + 2H2O (l) --> H2 (g) + 2NaOH (aq)
8. Remove a small lump of sodium from storage under oil.
Observe the layer of oxide / hydroxide on the surface of the sodium.
Cut a pea-size piece from the surface of the sodium.
Observe the shiny sodium metal surface that rapidly darkens, because of reaction with air and moisture.
9. Demonstrate the reaction of sodium with water in a fume cupboard or outside if students are protected by a safety shield, or wearing safety glasses.
Use a large beaker filled with water to within 1 cm of the top, so that there is no space for air / hydrogen mixture to accumulate.
Add a piece of sodium no greater in size than a rice grain, 3 mm diameter.
Use a wire gauze on top of the beaker to prevent the ejection of sodium.
The sodium fizzes around the surface of the water for a few seconds, reacting violently.
Add an acid / base indicator to the water, e.g. universal indicator or phenolphthalein, to demonstrate the alkalinity of the reaction products.
Demonstrate the disposal of waste sodium by reaction with ethanol or methylated spirit in a beaker in the fume cupboard as described above.
The sodium and may catch fire with the following reaction:.
Na + H2O--> Na+ + OH- + 1/2H2 (g)
10. Place sodium on wet absorbent paper and observe the ignition of the hydrogen gas.
This experiment can be used to test for the presence of alcohols.
Quantity of chemical Quantity of chemical to be used in school science experiments
Disposal of waste chemicals
1. In this document, "dilute solution" refers to a 2 M solution, or a 10% solution, unless otherwise specified.
2. In this document, "concentrated acid", or any other substance, refers to the concentration supplied by chemical suppliers,
e.g. concentrated hydrochloric acid is 36% w / w, unless otherwise specified.
3. For all experiments, unless otherwise instructed, use either:
3.1 a 5 mL of solution, or
3.2 a test-tube filled to the depth of a finger width, or
3.3 the powder on a little finger nail, or
3.4 a piece of solid chemical the size of half a dried pea, or
3.5 no more than one third of a test-tube of any solution.
4. Do not make gas jars full of gas for demonstration purposes.
Use test-tubes with stoppers to collect gases.
Quinidine, (C20H24N2O2), Quinoline Alkaloid
Quinidine, Chinidin, Pitayine, Cin-quin, optical isomer of quinine, antimalarial, anti-arrhythmic in the heart, dampens the excitability of cardiac and skeletal muscles, decreases conduction velocity of nerve impulses
It occurs in Chinchona tree bark.
See diagram: Quinidine.
Quinine, (C20H24N2O2), Quinoline Alkaloid
Quinine, Chinin, Chinine, Qualaquin, irritant, alkaloid derived from cinchona tree bark, antimalarial drug, active ingredient, mild antipyretic, analgesic so used in common cold preparations, used to treat idiopathic leg cramps.
Nowadays, it is used as a bitter and flavouring agent in Schweppes Indian Tonic Water
It occurs in cinchona tree extracts.
See: Quinine.
See diagram: Quinine.
Quinoline, (C9H7N), Quinoline Alkaloid
Quinoline, heterocyclic aromatic organic compound, colourless hygroscopic liquid, strong odour, if exposed to light yellow then brown, slightly soluble in cold water, flavouring ingredient
It occurs in Mentha species, in cocoa, in black tea, in scotch whisky.
See diagram: Quinoline.
Quinoline yellow, (C18H11NO2), mixture of dyes based on quinoline, quinophthalone, solvent yellow, erio chinoline yellow 4G, E104, azo dye based on quinoline, bright yellow colour, possible health risk is dermatitis, used in lipsticks.
Rescinnamine, (C35H42N2O9), Vinca Alkaloid
Rescinnamine, anti-hypertensive, tranquillizer
It occurs in Rauvolfia vomitoria
See diagram: Rescinnamine.
Reserpine, (C33H40N2O9), Indole Alkaloid
Reserpine, indole derivative alkaloid, monoterpenoid indole alkaloid, corynanthe type alkaloid, anti-hypertensive, antipsychotic, was used to control high blood pressure, tranquillizer, nowadays rarely used
It occurs in Rauvolfia sepentina.
See diagram: Reserpine
Retamine, (C15H26N2O), Quinolzidine Alkaloid
Retamine, Hydroxysparteine, hypotensive, diuretic
It occurs in Genista species.
See diagram: Retamine.
Reticuline, (C190H23NO4), Isoquinoline Alkaloid
Reticuline, benzylisoquinoline alkaloid, coclanoline, alkaloid precursor, (precursor of morphine)
It occurs in Papaver, in Cryptocarpa, in Romneya.
See diagram: Reticuline.
Retronecine, (C8H13NO2), Pyrolizidine Alkaloid
Retronecine, Senecifolinene, pyrolizidine derivative, non-ester, may cause liver damage from excessive consumption
It occurs in Borago officinalis, in Senecio vulgaris, in Tussilago farfara, borage leaf, comfrey, coltsfoot, in weeds in grain crops, e.g. Heliotropium, europaeum, in Echium plantagineum, in Crotalaria retusa.
See diagram: Retronecine.
Rhoeadine, (C21H21NO6), Isoquinoline Alkaloid
Rhoeadine, Rheadine, rhoeadan alkaloid, possibly antitumour
It occurs in Papaver species, (Papaver rhoeas, folk medicine, expectorant, sedative).
See diagram: Rhoeadine.
Rhombifoline, (C15H20N2O), Quinolzidine Alkaloid
Rhombifoline, Butenylcytisine
It occurs in Genista, in Ammodendron, Thermopsis species.
See diagram: Rhombifoline.
Ricinine, (C8H8N2O2, Pyrrolidine and Piperidine Alkaloid
Ricinine, Ricidine, Ritsinin, pyridine derivative, simple derivative of pyridine, pyridine alkaloid, pyridone, nitrile, alkyl aryl ether R-O-R', (where R is an alkyl group and R' is an aryl group), bitter white crystals, may cause toxic burning feeling in mouth and throat, nausea, vomiting, severe pain in stomach, diarrhoea, reactions, hepatic and renal damage, death, used as alkaloid marker for poisonous lectin ricin, e.g. in urine, toxic alkaloid, insecticidal
It occurs in Ricinus communis, castor seeds and leaves
See diagram: Ricinine
Castor oil, ricinoleic acid: 16.3.6.4.
Riddelline, (C18H23NO6), Pyrrolizidine Alkaloid
Riddelline, is a diester of retronecine (C8H13NO2), and a possible carcinogen. It occurs in Senecio riddelli, Senecio vulgaris, in Acobaea vulgaris, in Crotalaria, in Amsinckia.
See diagram: Riddelline.
Rotundine, (C21H25NO), Berberine Alkaloid
Rotundine, Tetrahydropalmatine, selective dopamine D1 receptor agonist, analgesic, adrenergic agent, non-narcotic analgesic, dopaminergic antagonist, antiprotozoal, (derived from a palmatine), anti-arrhythmic, antihypertensive, antipsychotic, sedative, tranquillizer
It occurs in Stephania sinica.
Rutaecarpine, (C18H13N3O), Indole Alkaloid
Rutaecarpine, Rutecarpine, Rhetine, a pyridopyrimidine, i.e. a pyridine fused to a pyrimidine, inhibits platelet aggregation, hypotensive, vasoldilator, in Chinese medicine, counteracts breakdown of caffeine, anti-inflammatory, vasorelaxation, from China with strong bitter taste.
It occurs in Tetradium ruticarpum, in Evodia rutaecarpa, in Hortia arborea.
12.11.3.21 Tests for lead
Add potassium iodide solution to solutions of lead salts to form a yellow precipitate that is soluble in boiling water.
Organic reagent: Rhodizonic acid, C6H2O6, (CO)4(COH)2, dihydrate: C6H2O6.2H2O, sodium salt (CO-CO.C.ONa)2, 0.1% aqueous solution
Add two drops of reagent to a sample of Group I precipitate still wet with acid.
A violet colour indicates the presence of lead.
Make a fresh solution of the reagent, if it has decolorized.
Rhodopin, C40H58O, carotenoid pigment (an alcohol), phototrophic bacteria
Rhodoxanthin
Rhodoxanthin, C40H50O2, xanthophyll carotenoid, carotenoid pigment, purple, Food additive E161f
Rhodoxanthin occurs in Yew tree
Rishitin
Rishitin, sesquiterpene, C14H22O2, polyol, terpenoid compound, antifungal, bacteriocidal, phytotoxic, phytoalexin
It is produced by Solanum tuberosum tubers infected by Phytophthora fungi.
Rose oxide
Rose oxide, C10H18O, monoterpenoid, fragrance chemical, roses oil, lychee, Gewurztraminer wines
Rubixanthin
Rubixanthin, C40H56O, xanthophyll carotenoid, xanthophyll pigment, red-orange, natural yellow 27, food colouring (Banned some countries)
It occurs in | Rose hips, (Rosa canina), Rosaceae | Apricot, (Prunus armeniaca), Rosaceae |