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Chemistry | U | V | W | X | Y | Z |

Table of contents
Chemistry U
Ulexite, B5O6(OH)6, Borax
Ultraviolet radiation, (UV)
Umbelliferone, C9H6O3
Units, SI, International system of units, [Système international d'unités (French)]: 6.3.0
Universal cleaning agent, DECON 90
Universal indicator: 36
Unsaturated fatty acids, (double bond =):
Unsaturated hydrocarbons, Tests for unsaturated hydrocarbons
Uracil, C4H4N2O2
Uranium, U
Uranyl, UO22+
Urea, CO(NH2)2
Urethane, NH2COOC2H5
Uric acid, C5H4N4O3
Uroblilinogen test
Ursolic acid, C30H48O3
USP, chemicals standards

Chemistry V
Table of Elements
Vacuum flask, Dewar flask, "Thermos" flask, Heat transfer by: 22.2.8
Valapotriate, C22H30O8
Valentinite, Sb2O3, antimony bloom
Valeric acid, CH3(CH2)3COOH, Pentanoic acid, valeric acid:
Valine, C5H11NO2, (Table of amino acids)
Valine, DNA codon
van der Waals forces, Allotropes, sulfur, carbon:
van der Waals forces, (van de Waals bonds): 3.01.7
van der Waals forces, Universal gas equation, Ideal gas constant, R, (PV = nRT): 20.0.7
van't Hoff factor, i, for dilute solutions: 24.1.08
Vanadium, V
Vanilla, vanillin
"Vaporguard", pyrethroid insecticide, for clothes-damaging moths in wardrobes
Vapour pressure, pure water, solution: 24.1.02
Varsol fluids, mineral spirits, white spirits, hydrocarbon solvents, replaced by Exxsol D solvents.
Vaseline, (trade name), petroleum jelly
Vasicine, C11H12N2O
Vegetable gums, food additives: 19.4.27
Vegetable juices as indicators, red cabbage: 5.6.9
Vegetable oils, plant oils: 16.6.3
Velocity, (speed): 6.3.03
Veratridine, C35H51NO11
Verbascoside, C29H36O5
Verbenone, C10H14O, monoterpene
Verdigris, Prepare verdigris with copper and vinegar: 12.11.1
Vermiculite:, (in potting mix)
Vermilion, HgS, Cinnabar:
Very toxic substances:
Vinblastine, C46H58N4O9
Vincamine, C21H26N2O3
Vincristine, C46H56N4O10
Vindoline, C25H32N2O6
Vinegar, (acetic acid)
Vinorelbine, C45H54N4O8
Vinpocetine, C22H26N2O2
Vinyl acetate, CH3COOCH:CH2, vinyl acetate monomer, VAM
Vinyl group, unsaturated monovalent radical CH2=CH--
Vinyl benzene, C8H8, C6H5CH=CH2, Styrene
Vinyl chloride, C2H3Cl:
Vinyl ethylene, C4H6, Butadiene
Vinyls, vinyl polymers: 3.6.13
Violaxanthin, C40H56O4
Viscosity, Stokes' law: 17.3.0
Volcano, Prepare volcanos with baking soda: 12.16.6
"Volasil", commercial silicone-based solvent to replace CFCs, e.g. carbon tetrachloride
Volatile oils, Essential oils: 16.6.1
Volatile substances, Abuse of volatile substances, inhalants: 11.11.01
Volatility of different liquids: 3.7
Voltage, EMF sources, Voltage produced by: 32.1.0
Voltaic cell, Galvanic cell: 33.84.1
Voltaic pile, Cells and batteries, dry cells: 33.3.00
Voltameter, Electrolysis of water: 15.5.4
Weston Standard Cell: 33.3.01
Volumetric flasks, Flasks, borosilicate glass flasks: 1.27
Vulcanization: 3.6.11, (rubber)

Chemistry W
Table of Contents
W/V , W/W:, (Agricultural chemicals)
Wallpaper paste, Prepare: 9.1.3
Warfarin, C19H16O4, Coumarin
Washing powders, Ionic surfactants:
Washing soda, Na2CO3
Waste chemicals bottles:
Wastes, Disposal of waste chemicals: 3.4.11
Watch glass: 1.39
Water glass
Watt, (Physics)
Wax, Melt candle wax: 8.1.13
Wax tapers, Burn paraffin wax tapers in chlorine:
Waxoline yellow, (dyes)
Weathering: 6.54, (Soil science)
Weedicides, herbicides: 16.7.0
Weigert's haematoxylin, microscopy stain: 3.13.6
Weigert's iron haematoxylin, Prepare: 3.13.6
Weight and pressure: 12.5.0, (Physics)
Wetting agents, Detergents in washing powders: 12.12.04
Wheat germ oil, yellow, contains vitamin E and octacosanol, C28H58O, said to have health benefits
Wheat starch and gluten:
Whey: 16.2.5
White, Albumen (egg white) and egg yolk: 16.7.10
White lead, lead (II) carbonate
White paraffin, Vaseline, (petroleum jelly)
White phosphorus, P: 7.33.2
White spirit
Whitening agents, Fluorescent whitening agents in washing powders:
Whitewash, Carbon dioxide with calcium hydroxide solution:
Wijs' solution, ICl, Iodine monochloride, (Tests for fats and oils)
Wine lactone, C10H14O2
Winkler method, Oxygen content of water, dissolved oxygen, DO: 18.3.2
Wipes, baby wipes
Wire gauze mat: 1.13
Witherite, BaCO3
Withholding period: 16.18.3
Wolframite, (Fe,Mn)WO4
Wollastonite, Ca3(Si3,O9), calcium silicate, table spar, calc-flints
Work and energy, kinetic energy and potential energy: 9.0.0
Work, Units of work and energy, joule and calorie, kilowatt-hour: 21.0.0
Workplace Health and Safety Act, 1995: 3.1.0
Wort, Yeast, fermentation, brewing, beer: 16.7.11
Wright's stain, Prepare Leishmann's stain: 3.19
Wrought iron, Cast iron alloy, steel, wrought iron: 5.5.12

Chemistry X
Table of Contents
X-rays: 27.23
Xanthan gum, Sols:
Xanthene dyes:
Xanthodrol, C13H10O2, 9-hydroxyxanthene, 9-xanthenol, urea tests, Toxic, flammable
Xanthone, C13H8O2
Xanthoproteic test, Tests for proteins: 16.6.6
Xenon, Xe
Xylene, C8H10, xylol
Xylenol, (CH3)2C6H3OH, 2,6-xylenol, 2,6-dimethylphenol, 2-hydroxy-m-xylene, (solvent, disinfectant)
Xylenol orange, C31H30N2Na2O13S, disodium salt, tests for metal ions, Toxic if ingested
Xylol, C8H10, xylene
Xylose, C5H10O5, (Aldoses and ketoses), (Table)
Xylulose, C5H10O5, (Aldoses and ketoses), (Table)

Chemistry Y
Table of Contents
9.206.3 Yeasts
12.1.41 Yellow snowstorm reaction, Copper (II) sulfate reduction to copper sulfide
16.2.7 Yoghurts
Yohimbine, C21H26N2O3
Young's modulus, E, elasticity, stress and strain: 34.5.04, (Physics)
Ytterbium, Yb
Yttrium, Y
Yuanhuacine, C37H44O10

Chemistry Z
Table of Contents
Zeaxanthin, C40H56O2
Zenker's solution, Prepare: 4.6
Zephiran, C6H5CH2N(CH3)2R, (where R = mostly n-C12H25), benzalkonium chloride, antiseptic
Ziehl Neelsen stain, Prepare Ziehl-Neelsen microscopy stain: 3.12
Zinc, Zn
Zincite, ZnO
Zineb, C4H6N2S4Zn: 16.6.6, (fungicide)
Zingerone, C11H14O3
Ziploc bags
Zirconium, Zr
Zircon, ZrSiO4
Zirconia, ZrO2
Zylon PBO fibre, PBO
Zylonite, Cellulose acetate: 3.5.8
Zymase, Tests for zymase and catalase in yeast: 9.3.12
Zymosan, β-1,3-glucan, found on yeast
Zytel polymer, Polyamides: 3.7.6

Unsaturated hydrocarbons, Tests for unsaturated hydrocarbons
Tests for unsaturated alkanes:
Tests for unsaturated fats, bromine water test:
Tests for unsaturated hydrocarbons, acidified potassium manganate (VII) solution:
Tests for unsaturated hydrocarbons, acidified potassium manganate:
Tests for unsaturated hydrocarbons, bromine water tests for unsaturation:
Tests for unsaturated hydrocarbons, ignition tests for unsaturation:

Uracil, C4H4N2O2
Uracil, (only in RNA), 2,4-Dihydroxypyrimidine, 2,4-Pyrimidinediol, C4H4N2O2
Uracil:, See: 1.
See diagram: Heterocyclic compounds: pyrimidines, uracil

Uranium, U, Table of Elements
Uranium properties:
Uraninite, UO2, pitch blende, pitch ore: 35.20.46
Uranium, U, fission: 35.20.47
Uranium, U, (Uranus planet, Greek god Ouranos), radioactive actinide, hard
grey metal from pitchblende and other ores.
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, r.d. 19.1,
M P = 1130oC, B P = 3820oC, Specific heat capacity: 117 J kg-1 K-1
Transuranic elements have atomic number > 92

Uranyl, UO22+
Uranyl acetate, Toxic if ingested, weakly radioactive, avoid direct contact by using disposable gloves
Uranyl magnesium acetate, Tests for Na:
Uranyl zinc acetate, Toxic if ingested, skin irritant, weakly radioactive
Uranyl zinc acetate mixture, solid < 0.1%, Not hazardous, but do not ingest

Urea, CO(NH2)2
Urea, CO(NH2)2, 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
De-icers, ice melts:
IBDU, slow release fertilizer:
Indoor air pollution, formaldehyde pollution:
Prepare urea-formaldehyde resin: 3.101
Reactions of urea with nitrous acid: 16.6.15
Reactions of urea with soda lime: 16.6.16
Reactions of urea with sodium hypochlorite: 16.6.14
Tests for urea, biuret test: 16.6.5
Tests for urea, urea forms biuret: 16.6.13
Urea-formaldehyde, thermoset plastics: 3.8.11
Urea acts as a base: 16.6.18
Urea agar medium: 9.2.21
Urea forms biuret: 16.6.13
Urea, Straight fertilizers and mixed fertilizers:
Urea with water: 14.2.2
Urease, Hydrolysis of urea with urease 16.6.17

Urethane, NH2COOC2H5, ethyl carbamate ester
Ethyl carbamate ester, CO(NH2)OC2H5, urethane:
Ethyl carbamate, blood flow in a fish: 9.217
Polyurethane, Polymer foam: 3.5.1
Urethane: 3.7.34
Urethane, carbamic acid ethyl ester, ethyl carbamate, ethylurethane
carbamate esters = urethanes, [R2NC(=O)OR', where R' not = H, R= ethyl]
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)

Uric acid
Uric acid, C5H4N4O3, formed in humans from breakdown of purines, cause of gout, 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, 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.

Vanadium, V
, 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
Vanilla species, Orchidaceae
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, (in creamy soda, creaming soda).
1. Vanilla pod, vanilla bean, pod of orchid Vanilla
2. Vanillin, C8H8O3, o-vanillin, 3-methoxysalicyaldehyde, 4-hydroxy-3-methoxybenzaldehyde,  (CH3O)(OH)C6H3CHO, phenolic
aldehyde, sweet-smelling, crystalline compound, flavour of chocolate, ice cream, in perfumes, pharmaceuticals,
odour threshold value: 2 × 109 molecules / mL of air,
3. Vanilla oil, vanilla essence, food fragrance and flavour, deodorizer, in creaming soda, (creamy soda).

Vaseline (trade name), petroleum jelly, soft paraffin, white paraffin, white petrolatum, saturated semi-solid of crystalline and liquid
hydrocarbons, carbon numbers < C25, made by dewaxing paraffinic residual oil, liquid paraffin is a liquid form of petroleum jelly,
mixture of alkanes > 12 C atoms / molecule, colourless, tasteless, mild laxative, popular low-cost lubricant but weakens latex in condoms.

Water, tap water, deionized (demineralized) water, distilled water, hard water, soft water
Meters, environment, "Scientrific", (commercial website)
Water quality products, "Scientrific", (commercial website)
"Clean Water Science Pack", plastic filters, active carbon, filter paper, (commercial)
Tap water, deionized or demineralized water, distilled water, hard water, soft water
Water quality, (commercial websites)
Water, (Chemistry): 24.0.0
Water, (Physics): 25.0.0
Water, (Primary): 19.0

24.0.0 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: 18.7.0
Distilled water, Deionized water:
Drinking water test media: 18.7.1
Electrophiles and nucleophiles, hydrogen chloride: 14.0
Fractional crystallization of sea water: 7.7.14
Make-up water, fill water: 18.7.47
Maximum density of water: 11.2.2
Water content of food: 19.3.01
Water gas, Reduce red iron oxide to iron: 10.10.3
Water glass, sodium or potassium silicate: 7.9.56
Water stills: 2.5, (Safety)
Waterproof bags, Ziploc bags

Boiling point of sodium chloride solution: 3.5.1
Boiling point of water: 3.5.0
Conductivity of water, deionized, distilled, tap water:
Conductivity of salt water string, electrolytic conduction on chamois:
Deionized water, Ion exchange resins:
Gases dissolved in a water sample: 10.5.7
Hardness in water, water hardness: 12.13.0
Ions in a water sample: 18.4.0
Maximum density of water: 11.2.2a
Reactions of metals with water: 12.15.0
Reactions of salts with water: 3.75
Sea water, Tap water substitute, haematoxylin + eosin stain, Scott's blueing solution: 1.9
Shrinking volume: 3.22.0
Tests for air and dissolved oxygen in water: 18.3.0a
Tests for hardness in water: 18.2.0
Tests for metal ions in water using EDTA chelates: 12.13.11
Tests for moisture content of plant organs: 9.3.15
Tests for water hardness, EDTA titration, Calmagite indicator:
Tests for water, Heat CuSO4.5H2O crystals: 8.2.1
Tests for water pollution: 18.8.0, (Environmental chemistry)
Tests for standing water: 18.5.0, (Environmental chemistry)
Tests for water to form lather: 12.13.1
Tests for water with cobalt (II) chloride paper: 8.2.2
Total dissolved solids, (TDS), in water: 18.2.0
Use of water
Reactions of non-metals with water:
Water hardness, EDTA, Calmagite:
Water hardness, EDTA, Eriochrome:
Water of crystallization: 3.2.0
Water of crystallization, hydrous salts: 3.30.8
Water in blood: 12.3.02 Water in blood
Water pollution: 18.7.0
Water, pH tests: 18.1.0
Water softening with ion exchange resin: 12.13.13

25.0.0 Water, (Physics)
Heat, Water bath "Scientrific", (commercial)

11.2.2 Anomalous properties of water, density
7.5.0 Boiling point, b.p.
3.5 Boiling point of water
34.5.03 Bulk modulus, modulus of incompressibility, K
37.5.0 Clouds
13.2.27 Coanda effect, spoon and water stream
4.146 Colours of water
23.6.1 Convection currents in water
Density, Water vapour, (Table) Deionized water, Ion exchange resins Distilled water
14.3.4 Falling water from a tap
18.7.47 Fill water, make-up water, (Swimming pools)
6.24 Freezing water expands, (Soils)
4.217 Heap up water up in a glass
4.216 Hold water in a sieve
23.2.7 Hope's experiment, maximum density of water
26.0.0 Ice
4.215 Lift the water surface
12.2.0 Liquid pressure
10.3.2 Lost volume, Shrinking mixture of liquids
11.2.2 Maximum density of water
37.7.0 Moisture enters the air, evaporation
37.8.0 Moisture leaves the air, precipitation
4.218 Pinch together water streams
6.10.0 Soil water, water uptake by plants
22.5.01 Specific heat capacity, shc
22.5.2 Specific heat of water by electrical method
4.31 Temperature of water at maximum density, 4oC
23.3.02 Thermal expansion of water, Fluid
11.4.05 Water-resistant, waterproof
23.7.8 Water is poor conductor of heat, boil water in a balloon
4.23 Water is a poor conductor of heat, boil water in a paper cup
4.196 Water does not compress
4.130 Water drop magnifier, lens
4.130 Water lens magnifier, water lens
18.7.0 Water pollution
12.2.0 Water pressure, hydrostatics
4.190 Water pressure changes with depth
4.192 Water pressure, size of the container
4.193 Water pressure is the same in all directions
19.0 Water, (Primary) Water rocket Water stream impulse
2.5 Water stills, (Safety)
4.199 Water wheel
22.10.1 Waterfall, (potential energy) Watermarks

Urine tests, tests for glucose:
Tests for urine, reagent dipsticks:
Tests for reducing sugars in urine, Benedict's solution: 9.141.2
Tests for urine, urine tests: 9.5.10

Water gas is a mixture of carbon monoxide and hydrogen gas.
Water gas forms when steam passes over hot coke or carbon.

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", "Brasso".
White spirit is a mixture of aliphatic and alicyclic C7 to C12 hydrocarbons, (cleaning solvent, paint thinner, remove oil
stains, clean oil-based paints from paint brushes).

See: Part 8. Food and nutrition, Dr Red nutraceuticals, Modified polyphenol technology in wine, (commercial)
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
Acidity of vinegar and wine:
Alcoholic fermentation, yeast, Saccharomyces cerevisiae: 6.6.18
Amine intolerance: 19.2.2
Chilli wine: 16.0
Cork taint of wine, Stelvin capsule: 3.29
Decanting: 10.11.02
Degrees proof, proof spirit: 3.7.3
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: 2.1.1
Fining, clarify wine to removing tannins and proteins with isinglass, gelatin, clay, egg white, milk, seaweed
Flavonoids, plant polyphenols:
Food labels, eggs: 22.24
Gas bags: 13.1.01, (See 3. Wine cask)
Laudanum, opium diluted in wine with cloves and other spices, formerly a medicine, e.g. "poppy-head tea"
Leavening agents:
Modified polyphenol technology in wines:
Palm wine, coconut toddy, palm wine, (arrack), kava: 16.8
Pasteurization and UHT: 19.3.12
Prepare vinegar from wine: 19.1.4
Prepare vinegar with Acetobacter aceti: 4.2.6
Silicon compounds, wine glass: 7.2.3, (See: Expeiments 3.)
Stain removal:, (See: wine, red, wine, white)
Tears of wine: 19.3.15
Tests for sulfites:, (See: 2.)
Tests for tartaric acid:
Tonic wines, herbal tonic wines: 5.04.5
Triple scale wine hydrometer: 10.2.3
Wine bottle lens: 28.10.6, (See: 4.)
Wine from grape juice, vinegar from wine: 4.2.4
Wine glass resonance:
Wine lactone: C10H14O2

Wood = secondary xylem, (Greek: xylon, wood)
Cells and tissue sections: 9.57
Distil wood, (destructive distillation):
Prepare gases from wood: 3.99
Prepare wood gas and wood tar: 16.10.4
Tests for wood: 9.144
Wood alcohol, CH3OH, methanol
Wood, cellulose, hemicellulose:
Wood cells, Eucalyptus, poplar, (Populus): 9.64
Wood, copper chrome arsenate, CCA:
Woody stems, wood: 5.08
Woody stem, hawthorn: 9.6.17

Wool wax, (lanolin)
Wool, burning test for natural fabrics: 4.2.2
Wool or cotton, burning test for natural fabrics: 4.2.6

Xenon Xe, Table of Elements
Xenon, Xe, (Greek xenos foreign, stranger), colourless, odourless, non-metal noble gas at room temperature and pressure, 0.00001%
of the atmosphere.
Xenon in lasers, fluorescent lamps
Xenic acid, xenon trioxide solution
Atomic number: 54, Relative atomic mass: 131.29, r.d. 3.52(165 K), m.p. = -112oC, b.p. = -108oC.
Specific heat capacity: 159 J kg-1 K-1

Xylene, xylol
Xylene solution: 1.12
Xylol, Toxic by all routes, highly flammable, Carbol xylol, biology solution: 1.4
Xylene and methylbenzoate, biology solution: 1.12
Xylene cleaning agents, solvents: 2.20.4
Xylene, C8H10, C6H4(CH3)2, m-Xylene anhydrous, 1,3-dimethylbenzene, solvent, Xylene, Toxic, flammable
Xylene, C6H3(CH3)2OH, dimethylbenzenes, (3 isomers not separated), (prepare polyesters, Terylene),
Xylene cyanol FF, C25H27N2NaO6S2, acid blue 147, cyanol FF, histology dye, Toxic if ingested
Xylenes, ACS reagent, 98.5% xylenes + ethylbenzene basis, Xylene isomer mixture, CAS Number 1330-20-7
Xylol isomers:
m-Xylol, m-xylene, (1,3-Dimethylbenzene), Metaxylene, C8H10
o-Xylol, o-xylene, (1,2-Dimethylbenzene), Orthoxylene, C8H10
p-Xylol, p-xylene, (1,4-Dimethylbenzene), Paraxylene, C8H10
Low cost: from hardware stores and paint stores, as xylenes (mixed dimethylbenzene isomers)
Xylene, curing agent for epoxy resin adhesives, surface coating, paint thinner, irritant, solvent for some marker pens and Canada balsam,
Xylol, oil-immersion microscopy clearing agent, removes immersion oil from objective, prepares embedded specimens and mounts.

Ytterbium, Yb
, Yb, (Ytterby, Sweden), lanthanide, soft, silvery, malleable, in lasers
Ytterbium oxide, Yb2O3 in alloys, catalysts
Ytterbium (III) chloride hexahydrate, YbCl3.6H2O, animal food tracker

Yttrium, Y
, Y, (Ytterby, Sweden), grey transition metal, protective oxide, red phosphorescence
Yttrium-90, reactor-produced medical radioisotope, half-life 64 hours, used to treat liver cancer.
Yttrium, elements Y with Eu and Tb in TV screens (future shortfall), in microwave ferrites
Yttrium (III) oxide, Y2O3, used to make "1-2-3" super conductor, YBa2Cu3O7

Zinc, Zn
, Table of Elements
Zinc, properties:
Zinc compounds
Zinc experiments
Zinc and zinc deficiency symptoms: 1.14.0, (Soil)
Zinc mineral: 35.20.50
Zinc residues:
Zinc toxicity: 3.6.16
Tests for zinc:, (See 10.)
Tests for zinc:

Reactions of zinc and zinc compounds: 12.21.1
Acids with zinc: 12.5.2
Alkalis with zinc: 12.5.3
Combustion of zinc: 12.5.1
Electrical energy, displacement of Cu by Zn: 3.84
Group 4 tests for Co2+, Mn2+, Ni2+, Zn2+:
Heat from displacement reaction: 14.1.6
Heat zinc with copper (II) oxide:
Heat zinc with sulfur:
Zinc displaces lead from lead nitrate solution: 12.14.1
Zinc dust decolorizes bromine water
Zinc plating, electroplating, of copper: 15.1.6
Zinc powder with iodine solution:
Zinc with copper (II) sulfate solution:
Zinc with copper in sulfuric acid:
Zinc with hydrochloric acid, Prepare hydrogen gas:
Zinc with iodine solution:
Zinc with dilute hydrochloric acid, Count bubbles, (rate of reaction): 17.1.1
Zinc with lead nitrate solution:
Zinc with sulfur, Synthesis reactions, (combination reactions):
Test a simple electric cell with copper and zinc in dilute sulfuric acid: 3.84.3

Zinc compounds
Smithsonite, basic zinc carbonate, calamine: 35.20.40
Sphalerite, ZnS, zinc blende: 35.20.41
Copper-zinc alloys, brass: 5.5.6
Smithsonite, (basic zinc carbonate, ZnCO3.2ZnO.3H2O): 35.20.40
Zinc acetate dihydrate, Zn(O2CCH3)2(H2O)2, zinc ethanoate, harmful if ingested, white granules, slightly
efflorescent, faint vinegar odour, at 200C.
Zinc benzoate, C14H10O4Zn
Zinc blende, ZnS
Zinc bloom, hydrozincite, Zn[(OH)3(CO3)]2.5H2O, weathering production zinc deposit
Zinc bromide, ZnBr2
Zinc carbonate, ZnCO3
Zinc (II) chloride, ZnCl2
Zinc chromate, ZnCrO4
Zinc cyanide, Zn(CN)2, white powder, or colourless, rhombic crystals, bitter almonds odour, decomposes at 800oC
Zinc fluoride, ZnF2, ZnF2.4H2O, colourless crystals, needles, white crystalline mass, melting point of 872oC
Zinc gluconate, C12H22O14Zn, in medicine for common cold
Zinc hydroxide, Zn(OH)2, amphoteric
Zinc iodide, ZnI2, beige powder, Harmful, corrosive
Zinc nitrate, Zn(NO3)2
Zinc oxide, ZnO
Zinc perchlorate hexahydrate, Zn(ClO4)2.6H2O
Zinc phosphate, Zn3(PO4)2, primer, rust prevention
Zinc phosphide, Zn3P2, dark grey crystals, or lustrous or dull powder, faint phosphorus or garlic odour, rat bait
Zinc potassium chromate, KZn2.(OH)(CrO4)2, yellow powder, green-yellow, odourless, metal priming paint against corrosion
Zinc residues: 3.7
Zinc sulfate, ZnSO4
Zinc sulfide, ZnS
Zinc sulfite, ZnSO3, zinc sulfite dihydrate
Zincate, Zn(OH)42
Zincite, ZnO, red oxide of zinc: 35.20.51
Zineb, C4H6N2S4Zn, fungicide: 16.6.6

Zinc carbonate, ZnCO3
Zinc carbonate, ZnCO3, harmful.
Smithsonite mineral: 35.20.40
Zinc carbonate, colourless crystals or white crystalline powder, odourless, evolves carbon dioxide at 300oC.
Zinc carbonate, ZnCO3, (basic zinc carbonate, ZnCO3.2ZnO.3H2O)
Zinc carbonate basic, ZnCO3.2ZnO.3H2O, smithsonite, calamine, (calamine lotion for itches and rashes)

Zinc (II) chloride, ZnCl2
Zinc (II) chloride anhydrous, ZnCl2, Harmful if ingested, corrosive to skin, eyes
Zinc chloride, Solution / mixture < 5%, Not hazardous Zinc chloride, hygroscopic white granules or crystals, fused pieces, or rods,
odourless, white fumes acrid odour, melts at 275oC
Zinc chloride with sodium hydroxide:
Zinc chloride, (soln), 32% in HCl soldering flux, "killed acid", tinner's fluid, butter of zinc, Harmful
Zinc chloride, killed acid, Append E, Environment danger, Corrosive, (COR 2331), used to clean copper

Zinc chromate, ZnCrO4
Zinc chromate, yellow rust prevention primer on Fe and Al, but chromium toxicity against such use
Highly toxic if ingested or absorbed through skin, do not inhale yellow, fine powder or yellow prisms, odourless
Zinc chromate, Solution / mixture < 0.1%, Not hazardous
Zinc chromite, chromium zinc oxide, ZnO.xCr2O3

Zinc nitrate, Zn(NO3)2
Zinc nitrate hexahydrate, hydrated, Zn(NO3)2.6H2O, Harmful if ingested,
Zinc nitrate, Explosive mixtures with combustibles and organic compounds, toxic fumes

Zinc oxide, ZnO
Dilute acids and basic oxides, zinc oxide:

Zinc oxide, ZnO, amphoteric, (sunscreen cream),
Zinc oxide, flowers of zinc, philosopher's wool, spartalite, zincite, zinc white, Chinese white
Zinc oxide, white solid turns yellow on heating, melting point 1975oC
Zinc oxide with ammonium nitrate and some water may explode.
Zinc oxide, ZnO, white to yellow, amorphous powder, r.d. 5.47, m.p. above 1 800oC, white pigment, zincite, white zinc, zinc white,
Chinese white, spartalite, craft, zinc sun cream medicine and other skin problems.

Zinc sulfate, ZnSO4
Prepare zinc sulfate crystals:
Tests for oxidizing agents by change in colour of zinc with copper (II) sulfate: 15.2.10

Zinc sulfate, ZnSO4, zinc sulfate(VI)-7-water, zinc sulfate heptahydrate, ZnSO4.7H2O, (electrochemical cells),
Harmful if ingested, sulfur dioxide formed when heated
Zinc sulfate, colourless rhombic crystals, transparent prisms or small needles, efflorescent in dry air
Zinc sulfate heptahydrate, ZnSO4.7H2O, For 0.1 M solution, 28.8 g in 1 L water
Zinc sulfate hydrated, goslarite, white vitriol, white copperas
Zinc sulfate monohydrate, ZnSO4.H2O, zinc sulfate heptahydrate, ZnSO4.7H2O, colourless, odourless, white rhombic crystals or
powder, r.d. 1.97, m.p. about 50oC, efflorescent in dry air, anhydrous at 200oC, decomposes above 500oC, white vitriol, zinc vitriol,
white copperas, gosla rite, in zinc deficiency medicines.

Zinc sulfide, ZnS
Models, inorganic, Zinc sulfide, "Scientrific" (commercial)
Zinc sulfide, ZnS, white-yellow solid, soluble, sublimes, phosphor, pigment, Toxic if ingested, skin irritant
Zinc sulfide, ZnS, colourless hexagonal crystals, or white / grey-white powder or yellow powder, in sphalerite
Sphalerite, ZnS, zinc blende: 35.20.41
Zinc sulfide with acids forms hydrogen sulfide gas.

Zirconium, Zr
Table of Elements
Zirconium, properties
Zirconium, Zr, (German zirkon zircon, zirconium ore), grey, lustrous transition metal.
SPADNS fluoride reagent solution, 500 mL,
indicator for zirconium

Zirconium, properties
Zirconium, Zr, (German zirkon zircon, zirconium ore), grey, lustrous transition metal.
An "iSlice Cutter" has an zirconium-oxide ceramic blade that never rusts.
Zirconium, alloys to resist corrosion, nuclear fuel rods, grey-white solid, transition element, in zircon ZrSiO4, zirconium wire used in
photography flash bulbs, camera flash cubes, e.g. "Magicube", nuclear reactor neutron absorber

An "iSlice Cutter" has an zirconium-oxide ceramic blade that never rusts.
Zirconium, alloys to resist corrosion, nuclear fuel rods, grey-white solid, transition element, in zircon ZrSiO4, zirconium wire used in
photography flash bulbs, camera flash cubes, e.g. "Magicube", nuclear reactor neutron absorber
SPADNS fluoride solution, 500 mL, (HO)2C10H3(SO3Na)2N=NC6H4SO3Na, indicates zirconium, thorium
Zircalloy, Zr + Sn, Fe, Cr
Zirconate (IV), ZrO3-
Zirconium (IV) oxynitrate hydrate, ZrO(NO3)2 xH2O
Zirconium acetate, C8H12O8Zr
Zirconium carbonate, Zr3CO8
Zirconium nitrate, Zr(NO3)4.5H2O, Toxic if ingested, inhalation harmful, skin sensitization, explosion by shock or friction or ignition,
Zirconium nitrate, use small amounts.
Zirconium nitrate with acids forms nitrogen dioxide gas.
Zirconium oxychloride octahydrate, ZrOCl2 8H2O
Zirconate, lead-zirconate-titanate, (PZT), Piezoelectricity:
Zirconium, pegmatite, ZrSiO4, silicate: 35.21.3
Zirconium (IV) oxide, ZrO2, zirconia, baddeleyite, for craft, fuel cell electrolyte.
Zirconium tungstate, ZrW2O8, negative thermal expansion
Zirconium vanadate, ZrV2O7, negative thermal expansion

Zircon is zirconium silicate, ZrSiO4
Zirconium (IV) silicate, Zirconium (IV) silicon oxide, ZrSiO4
Zircon, zirconium silicate, ZrSiO4, jacinth, jargoons, Matura diamonds, in ceramic glazes
Zircon, pegmatite, beryl, topaz, tourmaline: 35.21.3
Zircon sand
Zircon, Separate solids, density differences: 3.27

Zirconia, zirconium dioxide, zircon dioxide, ZrO2, zircon (IV) oxide, zircon-favas
Zirconia, substitute diamond, not "zircon".
Baddeleyite mineral contains zirconium oxide, zirconia, ZrO2
Cubic zirconia, (CZ), optically flawless, colourless, crystalline zirconium dioxide, ZrO2, synthetic jewellery, 8.5 Moh's hardness scale
Pink zirconia, diamond look-alike,zirconium dioxide, ZrO2, synthetic jewellery

8.2.1 Heat copper (II) sulfate-5-water crystals, test for water
See 3.80: Exothermic reactions, the reactants form products with rise in temperature
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:
3.1 To one part, in a test tube, add one drop of methylated spirit,
3.2 To the second part, in a test tube, add white spirit (dry cleaning fluid, C7 to C12 hydrocarbons),
3.3 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
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 this chemical 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.

12.21.1 Reactions of zinc and zinc compounds
1. Hold a piece of zinc foil in the Bunsen burner flame, using tongs.
Note the zinc oxide forms that is yellow when hot and white when cold.

2. Add sodium carbonate solution to zinc sulfate solution.
Observe the white precipitate of basic zinc carbonate, ZnCO3.2Zn(OH)2H2O.

3. Add sodium hydrogen carbonate to zinc sulfate solution.
Note the white precipitate of the normal carbonate, ZnCO3.

4. Add drops of sodium hydroxide solution to zinc sulfate solution.
Observe the white precipitate of zinc hydroxide that dissolves in excess of sodium hydroxide solution to form sodium zincate.
Pass hydrogen sulfide is passed through the sodium zincate solution.
Note the white precipitate of zinc sulfide.
Zinc hydroxide is amphoteric.
ZnSO4 + 2NaOH --> Zn(OH)2 + Na2SO4
Zn(OH)2 + 2NaOH --> Na2ZnO2 + 2H2O
(Note: Na2ZnO2 = sodium zincate)

5. Add drops of ammonium sulfide solution to zinc sulfate solution.
Note the white precipitate of zinc sulfide that may be discoloured.

6. Dip a rolled filter paper into a concentrated solution of zinc sulfate with added cobalt nitrate solution.
Burn the filter paper on wire gauze and note the remaining green ash, Rinmann's green.

7. Add drops of ammonium hydroxide to zinc sulfate solution.
The precipitate of zinc hydroxide dissolves in excess, due to the formation of a complex ion, [Zn(NH3)2]2+.