School Science Lessons
2025-01-30
Chemistry, U, V, W
Chemistry, U
Chemistry, V
Chemistry, W
Chemistry, U
Please send comments to: j.elfick@uq.edu.au
Contents
Ulexite, (Geology)
Ultraviolet radiation, (Experiments)
Umbelliferone
Umbelliferose
Units, CGS, m.k.s, newton
Units,, SI units, International system of units
Universal gas equation
Universal indicator, acid-base indicator, (Experiments)
Unsaturated fatty acids (double bond =)
Unsaturation, Tests for
Uracil, nucleotide base
Uranium, U
Uranyl, (UO2)2+
Urea, CO(NH2)2), (Experiments)
Urea-formaldehyde resin, Prepare
Urethane, (NH2(COOC2H5)
Uric acid, (C5H4N4O3)
Urine, (Experiments)
Urobilinogen, (Experiment)
Ursolic acid
Urushiol
Uscharidin
Chemistry, V
Contents
Vaccenic acid
Vacuum flask, Dewar flask, "Thermos" flask, (Experiments)
Valentinite, (See: Stibnite), (Geology)
Valepotriate
Valerenic acid
Valerianine
Valeroidine
Valeric acid
Valine, (Table of amino acids)
Valine, DNA codons
Valtratum
van der Waals forces, (See: Allotropes, sulfur, carbon)
van der Waals forces, (van de Waals bonds)
van't Hoff factor
Vanadium, V
Vanilla, Vanillin, C8H8O3
"Vaporguard", pyrethroid insecticide, for clothes-damaging moths in wardrobes
Vapour pressure of water
Varsol fluids, mineral spirits, white spirits, hydrocarbon solvents, replaced by Exxsol D solvents
Vaseline (trade name), petroleum jelly
Vasicine
Vegetable gums, List
Vegetable oils, List
Veracevine
Verbenalin
Verbascoside
Verbascose
Verdigris, Prepare verdigris with copper and vinegar
Veratramine
Veratridine
Verbascoside
Verbenone
Verdigris, Prepare
Vermiculite, (Geology)
Vermilion, Cinnabar, (Geology)
Verruculotoxin
Very toxic substances
Verticine
Vestitol
Victorin C
Vinblastine
Vincamine
Vincristine
Vindoline
Vinegar, Acetic acid
Vinorelbine
Vinpocetine
Vinyl acetate, CH3COOCH: CH2, vinyl acetate monomer, VAM
Vinyl group, unsaturated monovalent radical CH2=CH--
Vinyl benzene, Styrene, (Experiments)
Vinyl chloride, C2H3Cl
Vinyl ethylene, C4H6
Vinyls, vinyl polymers
Violaxanthin, C40H56O4
Viscidulin, lactone
Viscosity, Stokes' law, (Experiments)
Visnadine
Vitamins, List
Volcano, Prepare with baking soda
Volcano, Cooling candle wax, (Primary)
Volasil
Volatile oils, Essential oils, ethereal oils
Volatile substances, Abuse of volatile substances
Volatility of different liquids
Volume
Volumetric flasks, Flasks, borosilicate glass flasks
Vulcanization (rubber)
Vulgaxanthin
Chemistry, W
Contents
Wallpaper paste, Prepare
Warfarin
Washing powders, Detergents in washing powders
Washing soda, sodium carbonate, (Experiments)
Waste chemicals bottles
Wastes, Disposal of waste chemicals
Wastewater, National Wastewater Drug Monitoring Program
Watch glass
Water
Water gas
Watermarks, (invisible ink), (Experiments)
Watt, W, Power
Wax, (Experiments)
Waxoline yellow (dyes)
Weather science, (Experiments)
Weathering soils (Soils)
Weedicides, herbicides, (Agriculture), List
Weigert's iron haematoxylin Prepare
Weight, Mass
Weight and pressure, (Experiment)
Welding, Oxyacetylene welding
Weston Standard Cell
Wetting agents in detergents
White lead, lead (II) carbonate
White paraffin, Vaseline (trade name), petroleum jelly
White phosphorus, P, (Experiments)
White spirit, Dry cleaning spirit
Whitening agents, washing powders
Whitewash, whiting, (Experiments)
Wijs' solution, Iodine monochloride
Wine, (Experiments)
Wine lactone, C10H14O2
Winkler method, Oxygen content of water, dissolved oxygen
Wipes Cleaning, Baby wipes, (Commercial)
Wire, (Experiments)
Witherite, Barium carbonate
Withholding period, (Agriculture)
Wolframite, (Geology)
Wollastonite, CaSiO3, calcium silicate, building material, used to make rock wool
Wood, (Experiments)
Wool Tests for natural fabrics, burning tests, (See: 5.)
Wool wax (lanolin)
Work and energy
Workplace Health and Safety Act, 1995
Wort, brewing beer, (See: 5.)
Wright's stain, Leishmann's stain, Prepare
Wrought iron cast iron alloy
Uracil, C4H4N2O2
In RNA, thymine it is replaced with uracil, C4H4N2O2
The four nucleobases in the nucleic acid of RNA, thymine is replace by uracil, C4H4N2O2
Uracil. 2,4-Dihydroxypyrimidine, 2,4-Pyrimidinediol, one of four nucleotide bases in the nucleic acid RNA.
It base pairs with adenine and replaces thymine during DNA transcription, a prodrug, in humans
It occurs in Hamigera avellanea, and Paraphaeosphaeria minitans
Uracil: 16.3.2.8
Nucleic acid nitrogenous bases, (See: Uracil)
See diagram: Heterocyclic compounds: pyrimidines, uracil
Uranium, U
Uranium, U (Uranus planet, Greek god Ouranos), radioactive actinide, hard grey metal
Uranium metal and ores are Toxic if ingested, weakly radioactive, avoid direct contact by using disposable gloves.
Keep only small samples of uranium and its ores in demonstration containers.
Uranium, U, is a obtained from pitchblende U3O8, 238U main isotope.
235U is used as fuel in nuclear power stations, weapons fissile substances and atomic bombs.
Atomic number: 92, Relative atomic mass: 238.029, RD 19.1, MP = 1130oC, BP. = 3820oC, Specific heat: 117 J kg-1 K-1
Transuranic elements have atomic number > 92
Uranium, Table of the Elements
Uranium, RSC
Uraninite, (Geology)
Uranium, (Geology)
Uranyl, UO22+
Uranyl acetate, Toxic if ingested, weakly radioactive, avoid direct contact by using disposable gloves
Uranyl zinc acetate, Toxic if ingested, skin irritant, weakly radioactive
Uranyl zinc acetate mixture, solid < 0.1%, Not hazardous, but do not ingest
Tests for sodium: 12.11.3.27, Uranyl magnesium acetate
Urea, CO(NH2)2
Urea, carbamide, urea pure, urea fertilizer, E927b, Harmful
Prilled urea: Nitrogen: 46% min, Biuret: 1% max, Moisture: 1% max, Size: 0.85 - 2.8 mm, 90% min pass
Urea (carbamide), food acid, E927b, browning agent, deodorizer
Urea phosphate, UP, CH7N2O5P, urea phosphoric acid
Tests for urea, Xanthodrol, C13H10O2, (9-hydroxyxanthene), (9-xanthenol), urea tests, Toxic, flammable
Urea, stock poisoning
Ice melts, de-icers: 3.3.1
IBDU: 9.2.5, slow release fertilizer:
Indoor air pollution: 18.6.4, formaldehyde pollution
Prepare urea agar solution: 1.18
Prepare urea-formaldehyde resin: 3.3.12
Prepare urea agar solution: 1.18
Prepare phenylthiourea solution: 3.19, PTU
Reactions of urea: 16.5.4, Biuret
Reaction of urea with water: 14.2.2
Tests for proteins, biuret test: 9.4.2
Urea-formaldehyde, thermoset plastics: 3.8.11
Urea, Straight fertilizers and mixed fertilizers: 9.2.13
Urease, Hydrolysis of urea with urease16.5.4, (See: 5.)
Urethane, NH2COOC2H5
Urethane, ethyl carbamate ester, odourless colorless crystals formed by the condensation of ethanol with carbamic acid.
Urethane may can cause cancer and developmental toxicity.
Urethanes form when the isocyanate group (-NCO) reacts with (-OH) group to form a urethane, similar to amide bonds in nylon.
Polyurethanes are synthetic resins containing the repeating group -NH-CO-O-.
Urethane, Polyurethanes, PUR (PU), "urethanes", poly-formaldehyde, (some are thermoset plastics)
3.7.34.
Urethane: 7.9.54.2
Carbamates: 16.1.5.6a
Ethyl carbamate, blood flow in a fish: 9.1.5
Polyurethane, Polymer foam: 3.5.1
Uric acid, C5H4N4O3
Uric acid is the last product of purine metabolism in humans.
Excess uric acid in the blood may cause gout and formation of kidney stones.
Uric acid is seen as white crystals in bird droppings, component of guano.
Animals that lay eggs on land use uric acid excretion, because uric acid is only slightly soluble in water so easily precipitates out of solution
Uric acid is not toxic and does not exert osmotic pressure on the embryo.
Unlike excretion of urea, it does not require large amounts of water.
However, excretion by uric acid requires much more energy than excretion by urea.
Urine
Urine Test Strips, (Wellcome), (Commercial)
Tests for urine, reagent dipsticks: 19.5.5H
Tests for reducing sugars in urine, Benedict's solution: 9.4.0
Electrolytes in the blood and urine: 15.2.4
Urobilinogen, C33H44N4O6
Urobilinogen, msobilirubinogen, colourless substance, formed in the intestine from the reduction of red-orange bilirubin, C33H36N4O6.
Some urobilinogen is excreted in the faeces where it is oxidized to urobilin, C33H42N4O6, which causes the yellow colour of urine.
Some urobilinogen is reabsorbed and re-excreted in the bile, and later in the faeces, as bilirubin.
Some urobilinogen is re-excreted in the urine, where it may be later oxidized to urobilin.
Low values of urobilinogen in a urine test may indicate the liver is not working correctly.
High values of urobilinogen in a urine test may indicate liver disease, e.g. hepatitis or cirrhosis.
Experiment
Urobilinogen test
Ehrlich's benzaldehyde reaction is a test for urobilinogen in the urine:
Dissolve 2 g of dimethyl-p-aminobenzaldehyde in 100 mL of 5% hydrochloric acid and add this reagent to urine.
A red colour in the cold indicates the presence of an excessive amount of urobilinogen.
Uscharidin, C29H38O9
Uscharidin is a cardenolide glycoside, cyclic bridged cardiac glycoside, toxic to vertebrates
It occurs in Calotropis procera, Thymus vulgaris, and Asclepias subulata.
Vaccenic acid, C18H34O2
Vaccenic acid, (11-Octadecenoic acid), is an octadecenoic acid, a straight-chain fatty acid, possible growth promoting factor.
It occurs in the seed oil of Macfadyena unguis-cati, and in milkweed, Asclepias syriaca
Vanadium, V
Vanadium, Table of the Elements
Vanadium, RSC
Vanadium, V, (Latin Vanadis Scandinavian goddess), grey, hard transition metal, in steel alloys
Vanadium, AAS standard
Vanadium benzoyl acetone
Vanadium pentoxide, vanadium (V) oxide
Harmful by all routes, do not inhale dust particles
Vanadium pentoxide, Solid / mixture < 25%, Not hazardous, but do not ingest
Vanilla, Vanillin, C8H8O3
Vanilla (Vanilla planifolia), Orchidaceae, vanilla bean, vanilla pod
Also vanilla vine, Vanilla pompona, West Indian vanilla, Orchidaceae
Vanilla essence, vanilla oil, essence, food fragrance and flavour, deodorizer, in creaming soda, (creamy soda)
Australian brand "Vanilla Bean Dusting Sugar" contains icing sugar, cornstarch and vanilla bean powder.
1. Vanilla pod, vanilla bean, pod of orchid Vanilla.
2. Vanilla oil, vanilla essence, food fragrance and flavour, deodorizer, in creaming soda (creamy soda).
3. Vanillin, C8H8O3, (4-Hydroxy-3-methoxybenzaldehyde), vanillaldehyde, phenolic aldehyde, vanilla aroma, main component of the vanilla bean, sweet-smelling, crystalline compound as white-yellow needles, flavouring agent used in ice cream and perfumes and pharmaceuticals, antioxidant, anticonvulsant.
Vanillin can be synthesized, but food-grade vanillin (> 99% pure) is made from guaiacol, C6H4(OH)(OCH3), from plants.
4. Artificial vanilla flavouring, synthetic vanillin, made from guaiacol or from lignin, flavouring agent, in foods, in beverages, in pharmaceuticals,
because of scarcity and expense of vanilla bean.
5. Ethylvanillin, 3-Ethoxy-4-hydroxybenzaldehyde, Bourbonal, C9H10O3, aromatic ether, colourless crystals, more intense vanilla odour, and taste than vanillin,
antioxidant, flavouring agent, flavouring power 2-4 times greater than vanillin, used in cocoa product.
Vaseline
Vaseline (US trade name), petroleum jelly, soft paraffin, white paraffin, saturated semi-solid of crystalline and liquid hydrocarbons, (carbon numbers > 25)
Liquid paraffin is a liquid form of petroleum jelly, mixture of alkanes > 12 C atoms / molecule, colourless, tasteless, low-cost lubricant
Vaseline weakens latex in condoms, so should not be used for contraception.
Vaseline may be called "mineral oil" in formula of cosmetics.
Vestitol, C16H16O4
Vestitol, (2',7-dihydroxy-4'-methoxyisoflavan),hydroxyisoflavan, methoxyisoflavan, is an aromatic ether, anti-inflammatory.
It occurs in Glycyrrhiza uralensis and in human gut microbiota.
Victorin C, C31H45Cl3N6O13
Victorin C, is a heterodetic cyclic peptide, organochlorine compound, secondary alpha-hydroxy ketone.
It is a mycotoxin in fungus Cochliobolus victoriae.
Viscidulin B, C17H22O5,
Viscidulin B is a sesquiterpene lactone, guaianolide, plant growth regulator, occurs in sticky sagebush Artemisia cana var. viscidula
Visnadine, C21H24O7
Visnadine, cardine, carduben, provismine, vibeline, visnamine, is a coumarin, irritant, environmental hazard, coronary vasodilator, spasmolytic.
It occurs in bishop's weed Ammi visnaga seeds, in Anethum, in Ferula.
Volasil
'Volasil® 995', Decamethylcyclopentasiloxane, D5, D5, [(CH3)2SiO]5, silicone-based solvent. sold to replace CFCs, e.g. carbon tetrachloride.
A volatile cyclic silicone, low viscosity, non-polar, insoluble in water, miscible in lower alcohol, low heat of vaporization.
It is used to remove paint overspray, and in personal care formulations.
Valerianine, (C11H15NO), Monoterpenoid and Sesquiterpenoid Alkaloid
Valerianine, occurs in Valeriana officinalis roots.
See diagram: Valerianine.
Veracevine, (C27H43NO8), Steroidal Alkaloid
Veracevine, Veratridine, Protocevine, cyclic hemiketal, heptol, tertiary amino compound, tertiary alcohol, secondary alcohol, insecticide
It is used as a source of veratridine or cevine.
See diagram: Veracevine.
Veratramine, (C27H39NO2), Steroidal Alkaloid
Veratramine, in Veratrum species rhizomes, extracts of Veratrum viride used a veterinary medicine.
See diagram: Veratramine.
Veratridine, (C35H51NO11), Steroidal Alkaloid
Veratridine, Benzoate-cevane, Dimethoxybenzoate, (derivative of veracevine alkaloid, protocevine, (C27H43NO8), neurotoxin, activates sodium channels to remain open longer, sodium channel modulator, occurs in lily family, Veratrum used to treat nervous disorders, pain, occurs in Schoenocaulon officinale, Sabadilla seeds, in Veratrum album, rhizome.
See diagram: Veratridine.
Verruculotoxin, (C15H20N2O), Unclassified Alkaloid
Verruculotoxin, organonitrogen heterocyclic compound, organic heterobicyclic compound, toxic, mycotoxin in Penicillium veraculosum, hypogoea
It causes ataxia and loss of muscle control in day-old chicks.
It occurs in Arachis (green peanuts).
See diagram: Verruculotoxin.
Verticine, (C27H45NO3), Steroidal Alkaloid
Verticine, Peimine, used to treat chest disorders, occurs in Fritillaria.
See diagram: Verticine.
Warfarin
Warfarin, C19H16O4, is an odourless, colourless solid, and has popular use as an oral anticoagulant.
It can cross the placental barrier during pregnancy and cause abortion.
Can cause purple toe syndrome, (blockage of small blood vessele), osteoporosis, blood vessel calcification,
Warfarin: Coumarin, C9H6O2
Water
Water, (chemical formula: H2O), tap water, deionized or demineralized water, distilled water, hard water, soft water
Water, clear liquid, widely used solvent used in aqueous solutions, an oxygen hydride and amphiprotic (can donate or accept an additional proton).
It is an inorganic hydroxy compound, which exists in liquid state, solid state (ice) and gaseous state (steam, water vapour).
Sterile water is used for injections and body irrigation.
Purified water, strength about 98.6 mL / 100 mL, has contaminants removed for public access tap water.
Distilled water is free of all contaminant and minerals, but is more expensibe than deionized water.
Deionized water, (demineralized water), is produced by a resin-based water filtration process of removing all dissolved solids from the water.
DI ion exchange resin attracts non-water ions and replaces them with water ions, leaving a more pure water form.
Bottled water is purified water and convenient to use, but expensive compare to tap water.
In 1795, the kilogram was defined in France as the mass of one litre of water..
1 mL of water weighs 1 gram, 1 g.
WaterAid Australia
Water Global Water Partnership
Water (Chemistry): 24.0.0
Water (Physics): 25.0.0
Water pollution: 18.7.0
Water (Primary): 19.0
Soil water: 6.8.0 (Agriculture)
Water bag: 24.3.4, Coolgardie safe
Water "lost" by evaporation: 24.3.10
Water crystals in soap film: 24.10.13
Water, (Chemistry)
Water (aqua), H-O-H, monodentate ligand
Water, tap water, deionized or demineralized water, distilled water, hard water, soft water
Water gas, mixture of carbon monoxide and hydrogen gas, forms when steam passes over hot coke or carbon.
Bottled Water: 18.7.2
Drinking water test media: 18.7.1
Evaporation of sea water: 7.7.3
Make-up water, fill water: 18.4.6, swimming pools
Temperature of water at maximum density: 10.2.6
Triple point and ice point temperatures of water: 6.7.8
Water content of food: 19.2.16
24.10.13 Water crystals in soap film
Water retention agents: 19.1.17
Water of crystallization: 3.6.0
Water stills: 2.2.13 (Safety)
Water use: 19.3.5, Household chemicals
Experiments
Conductivity of water, deionized, distilled, tap water: 32.2.4
Gases dissolved in water: 10.6.0
Hardness in water: 12.2.0, water hardness
Make-up water: 18.4.67, fill water, (Swimming pools)
Maximum density of water: 11.2.8
Pressure and boiling point of water: 24.11.5
Separate gases dissolved in a water sample: 10.3,5
Water in blood: 9.1.9
Water pollution: 18.7.0
Tests for water
Tests for water: 18.7.0
Tests for moisture content of plant organs: 9.3.14
Tests for water hardness: 12.3.0
Tests for water with anhydrous copper(II) sulfate: 8.2.1
Tests for water with cobalt (II) chloride paper: 8.2.2
Water, (Physics)
34.8.3 Bulk modulus, modulus of incompressibility, K
37.5.2 Clouds in a bottle
13.2.13 Coanda effect, spoon touches a water stream
23.6.4 Convection currents between jars of water
12.4.0, Water vapour (Table)
2.5 Deionized water, Ion exchange resins
6.3.1.3 Distilled water, deionized water
14.3.4 Falling water from a tap
10.3.0 Flotation
6.8.12 Freezing water expands, (Soils)
19.4.12 Heap up water in a glass
19.4.14 Hold water in a sieve
23.6.13 Hope's experiment, maximum density of water
26.0.0 Ice
19.4.15 Lift the water surface
12.1.0 Liquid pressure, fluid pressure, hydrostatics
11.2.8 Maximum density of water
37.7.0 Moisture enters the air, evaporation
37.8.0 Moisture leaves the air, precipitation
19.4.19 Pinch together water streams
24.11.5 Pressure and boiling point of water
6.8.0 Soil water
22.5.3 Specific heat capacity, (c or she), for water
22.4.2 Specific heat of water by electrical method
Tests for water
23.3.02 Thermal expansion of water
11.4.29 Water-resistant, waterproof
24.3.4 Water bag, Coolgardie safe
24.3.10 Water "lost" by evaporation
23.7.1 Water is poor conductor of heat, boil water in a balloon
23.7.2 Water is a poor conductor of heat, boil water in a paper cup
12.1.18 Water does not compress
28.130 Water drop magnifier, lens
18.7.0 Water pollution
12.1.15 Water pressure changes with depth
12.1.16 Water pressure does not depend on the size of the container
12.1.13 Water pressure is the same in all directions, Pascal's fountain
12.1.42 Water rises in a downwards floating beaker, Pressure under an inverted beaker
19.0 Water (Primary)
Water gas
16.3.19 Water hammer
17.7.9 Water jet reaction force
17.7.10 Water rocket
17.6.27 Water stream impulse
2.2.13 Water stills, (Safety)
12.1.17 Water wheel
22.4.8 Waterfall
3.2.16 Watermarks
18.7.2 Bottled water
1. For many years, people relied exclusively on rain water or tap water for drinking.
Now that consumers are turning to bottled water as the healthy and "pure" alternative to tap water, are we really just wasting our money and the environment?
Spring water is extracted from natural sources.
Other bottled water is simply water from the municipal water supply that has been subjected to additional treatment.
Consumers may claim that bottled water is convenient and that it tastes better than tap water.
It is also marketed as the healthy alternative to sugared drinks and as the most "pure" available water.
2. Te health arguments for bottled water are overstated.
The choice is not one between sugared drinks and bottled water, but between bottled water and tap water.
There is no evidence that bottled water is more "pure" than tap water, but plenty of evidence to suggest that bottled water is costly both to the hip pocket and to the environment.
3. During extraction, spring water is extracted from underground aquifers upstream from where the water surfaces.
This disrupts aquifer flow, affecting flora and fauna.
4. In production, most bottled water is packaged in PET (polyethylene terephthalate) plastic bottles, from crude oil.
It can take up to 3L of water to produce 1L of water.
5. Transportation of bottled water around the world requires burning of fossil fuels.
In landfill and the litter stream, although plastic bottles are recyclable, many end up in landfill and take up to 1000 years to break down.
When littered they often end up in the sea where they break up in small pieces, killing marine life that mistake them for food.
6. The best thing to do is to avoid bottled water.
Australian tap water is world standard drinking water, so it is the safe, cheap and sustainable option.
Install a tap filter if you are concerned about the taste or quality of your local tap water.
Buy a reusable bottle.
There is a great range available from camping stores and other retailers.
8.2.1 Tests for water with anhydrous copper(II) sulfate
1. Use anhydrous copper (II) sulfate to test for the presence of water.
Heat the crystals gently in a test-tube until they change from blue to white.
Water vapour collects on the side of the test-tube.
Cool the test-tube.
Put some condensed water vapour on the white substance, anhydrous copper (II) sulfate.
The copper (II) sulfate turns blue again.
This is an example of a reversible change.
The return of the blue colour is also a test for water.
(In this direction, heat enters the reaction. --->).
(<--- In this direction, heat leaves the reaction.).
CuSO4.5H2O (s) <--> CuSO4 (s) + 5H2O (l)
2. Heat copper (II) sulfate crystals to make it lose its water of crystallization and leave anhydrous copper (II) sulfate as a white powder.
The lost water appears as drops on the inner surface of the upper part of the test-tube.
Test the drops for the presence of water with blue cobalt (II) chloride paper.
Transfer the anhydrous copper (II) sulfate to another test-tube and add a drop of water.
The blue hydrated salt forms again.
3. Put a finger width of copper sulfate in a test-tube.
Use a test-tube holder to keep the test-tube horizontal and heat the copper sulfate over the spirit burner flame.
To avoid overheating, move the test-tube in the flame or move the flame up and down under the test-tube.
Observe the copper sulfate crystals turning white and water condensing on the cooler parts of the test-tube.
Repeat the experiment by heating a finger width of copper sulfate crystals in an evaporating basin.
Heat the crystals slowly and stir the powder with the glass rod until all the blue colour has just disappeared.
Do not heat more, because the white powder will darken.
Leave the evaporating basin to cool.
Divide the white powder into three parts:.
Part 1. To one part, in a test tube, add one drop of methylated spirit.
Part 2. To the second part, in a test tube, add white spirit (dry cleaning fluid, C7 to C12 hydrocarbons).
Part 3. To the third part, remaining in the evaporating basin, hold the evaporating basin in the palm of your hand, and add water.
Describe what you see and what you can feel.
Only the water turns the powder blue and gives out heat that you can feel in your hand.
Store and label the dry copper sulfate crystals.
8.2.2 Tests for water with cobalt (II) chloride paper
1. Test for the presence of water with blue cobalt (II) chloride paper.
Soak paper in anhydrous cobalt (II) chloride and store in a desiccator.
Heat cobalt (II) chloride-6-water crystals.
The reaction forms the dark blue anhydrous cobalt (II) chloride with the loss of water.
Add water to anhydrous cobalt chloride.
The solution becomes pink.
Evaporate the pink solution to form purple crystals.
[In this direction, heat enters the reaction. -->].
CoCl2.6H2O (s) [pink] <--> CoCl2 (s) [blue] + 6H2O (l)
[<-- In this direction, heat leaves the reaction.].
2. To add water to the cobalt chloride crystals, grasp the cool test-tube and add water, drop by drop.
The blue crystals turn pink, and the test-tube feels hot.
When water is added, heat is given out.
Cobalt chloride combines with the water and becomes as before being heated.
The colour change when adding water is used as tests for the presence of water.
3. Use cobalt chloride to test for the presence of water.
Dissolve 5 g of cobalt (II) chloride in 100 mL deionized water.
Cut strips of absorbent paper 5 cm × 1 cm and soak them in the cobalt (II) chloride solution.
Remove the strips, drain and spread flat them on trays.
Place the trays in an oven at 100oC until the strips are blue.
Put strips in a bottle containing dry silica gel (blue in colour) or anhydrous calcium chloride.
Keep the bottle sealed, preferably in a desiccator.
If the paper turns pink, heat it again as described above until it turns blue again.
Do not handle the paper with fingers as moisture from the skin will affect it.
4. Heat pink cobalt chloride crystals
The crystals turn blue and water condenses on the cooler part of the test-tube.
Store and label the dry cobalt chloride crystals, CoCl2.
Water gas
Water gas is a mixture of carbon monoxide and hydrogen gas.
Water gas forms when steam passes over hot coke or carbon.
(ΔH = + 131 kJ / mol)
H2O + C --> H2 + CO
6.3.1.3 Distilled water, deionized water
1. Distilled water, as sold by Sigma-Aldrich
Distilled water, CAS Number 7732-18-5, Empirical Formula (Hill Notation) H2O, Molecular Weight 18.02
Beilstein Registry Number 2050024, EC Number 231-791-2, MDL number MFCD00011332, refractive index n20 / D 1.34(lit.)
bp 100 °C (lit.), density 1.000 g / mL at 3.98 °C (lit.), [conductivity 0.05 μS / cm (microSiemens / cm)]
2. Water deionized, deionized water, as sold by Sigma-Aldrich, exactly the same as above, except it also includes the following information:
conductivity ≤4.3 μS / cm at 20 °C
3. Deionized water really has no ions, except for H+ and OH- ions, but it may be not as pure as distilled water if it contains organic molecules.
Low cost: Purchase distilled water at supermarkets or garages.
For many chemistry and physics experiments, cheaper demineralized water is a suitable substitute for the dearer distilled water.
Waxoline
Waxoline yellow AD (C.I. Solvent Yellow 2) | Waxoline yellow ED (C.I. Solvent Yellow 56) | Waxoline yellow ED (Hodgson Oil Yellow GE)
Waxoline yellow I (C.I. Solvent Yellow 14) | Waxoline yellow T (C.I. Solvent Yellow 33)
White spirit
White spirit, dry cleaning spirit, petroleum distillate, Highly flammable, toxic by inhalation.
Stoddard solvent, mineral spirits, mineral turpentine, turpentine substitute, petroleum spirits, solvent naphtha, varsol, dry cleaning fluid, in "Murlex", in "Brasso".
White spirit is a mixture of aliphatic and alicyclic C7 to C12 hydrocarbons, (solvent, paint thinner, remove oil stains, clean oil-based paints from paint brushes).
Wine
1 glass, wine glass = 1 / 4 cup, 1 cup, cupful = 284 mL, 1 cup, teacup, (cup with a saucer) = 200 - 250 mL
1 magnum = 2 English wine bottles (2 "reputed" quarts), 1 rehoboam = 6 English wine bottles
Acetobacter aceti, spoils beers and wines, oxidizes ethanol, producing acetic acid
Alcoholic fermentation, yeast, Saccharomyces cerevisiae: 9.1.1
Amine intolerance: 19.2.1/a>
Chilli wine: 4.4, (See: 7.)
Cork taint of wine: 9.1.11, Stelvin capsule
Decanting: 10.11.1
Degrees proof, proof spirit: 6.2.4
E223 Sodium metabisulfite (preservative, flour treatment agent) (Health risk, asthma, dermatitis) (in soft drinks, dried fruit, wine)
E224 Potassium metabisulfite (preservative, antioxidant) (Health risk, allergy reaction hyperactivity) (in soft drinks, dried fruit, wine)
E225 Potassium sulfite (preservative, antioxidant) (may asthma, hyperactivity, behavioural problems) (in soft drinks, dried fruit, wine)
E228 Potassium hydrogen sulfite (preservative) (Health risk, hyperactivity, intestinal problems) (in soft drinks, dried fruit, wine)
E957 Thaumatin (protein from plant Thaumococcus danielli (artificial sweetener, flavour enhancer) (used with wine, bread, fruit)
Fermentation, Safety in school science: 4.1.9
Fining wine: To clarify wine by removing tannins and proteins with isinglass, gelatin, clay, egg white, milk, seaweed.
Flavonoids, plant polyphenols
Food labels, eggs: 13.9
Gas bags: 13.3.1 (See: 3. Wine cask)
Laudanum, opium diluted in wine with cloves and other spices, formerly a medicine, e.g. "poppy-head tea"
Palm wine, coconut toddy, palm wine (arrack), kava: 5.13.9
Pasteurization of milk: 19.3.12
Preservatives, food additives: 19.1.21, (See: E220 to E228)
Stain removal: 19.4.5 (wine, red, wine, white)
Tears of wine: 19.3.26
Tests for sulfites: 19.5.3, preservatives
Tests for tartaric acid: 19.5.4
Tonic wines: 5.5.5, Prepare
Triple scale wine hydrometer: 10.2.8
Vinegar: 9.1.7, (Experiments)
Wine bottle lens: 28.10.6 (See: 4.)
Wine from grape juice, vinegar from wine: 4.4.8
Wine glass: 7.4.9, Water glass, (See: 3. and 5.)
Wine glass resonance: 12.4.7
Wine with modified antioxidants: 4.4.9
Wine lactone: C10H14O2
Wood
Wood = secondary xylem, (Greek xylon wood)
Cells and tissue sections: 9.1.7
Distil wood (destructive distillation): 16.10.4.1
Pitch
Prepare gases from wood: 3.99
Prepare wood gas and wood tar by heating sawdust: 16.5.2
Tests for wood: 9.3.22
Wood alcohol, CH3OH, methanol
Wood, cellulose, hemicellulose: 16.1.1
Wood cells, Eucalyptus, poplar (Populus): 9.1.20
Wood, copper chrome arsenate, CCA: 12.2.2.1
Woody stem, hawthorn: 9.9.12