School Science Lessons
2019-03-24
Please send comments to: J.Elfick@uq.edu.au

Chemistry O
Table of Contents
Obsidian:
35.21.5.1 (Geology)
Ocimene, C10H16
Octadecanoic acid, CH3(CH2)16COOH, stearic acid
Octane (C8H18)
Octadecan-1-ol, C18H38O: 16.6.8.1
Octanoic acid, CH3(CH2)6COOH
Octanol, CH3(CH2)7OH: 16.6.8.2
Octopamine hydrochloride, C8H12ClNO2
Odour and taste: 35.15
Odour, Nose and smelling, taste, flavour, odour: 9.6.0
Oils
Ointments, creams: 5.04.8
Oleandrigenin, C25H36O6
Oleandrin, C32H48O9
Oleanolic acid, C30H48O3
Oleic acid, C17H33COOH
See: Oleic acid, model, (Commercial)
Oleoresins "gums": 16.4.0
Oleum, fuming sulfuric acid
Oleuropein, C25H32O13
Oligosaccharides
Olive (Olea europaea), Oleaceae (Agriculture)
Olive oil
Olivine group (Mg Fe)2SiO4 (Geology)
Omega-fatty acids, Trans fats: 19.2.1.7.2
Onyx, SiO2, Chalcedony: 35.14.4 (Geology)
Opal, SiO2.nH2O: 35.14.2 (Geology)
Optical bleaches, Fluorescent whitening agents in washing powders: 12.12.03.3a
Optical devices (low-cost): 28.11.0
OR (Organic reagent), chemicals standards
Oral contraceptives: 10.7.8
Orange IV (Tropeolin OO): 26 (indicator)
Oranges (fruit)
Orcein, Prepare aceto-orcein, C28H24N2O7: 3.2
Orcinol, CH3C6H3-1, 3-(OH)2, Prepare Orcinol-Bial's reagent: 6.12
Ore, Separate to metals by reduction of metal oxides, charcoal blocks: 10.10.0
Ores and ore bodies: 35.3.0
Organic gardening: 6.17.1.5
Organic chemistry
Organochlorine insecticides: 16.2.1
Organometal compounds: 16.2.3
Organophosphate and carbamate insecticides: 16.2.2
Organosulfur compounds: 16.4.6.0
Orlon polymer, Polyacrylonitrile: 3.7.5
Ormolu
ORP (Oxidation-Reduction Potential): 18.7.50
ORS (Oral Rehydration Salts), Children with diarrhoea, ORS special drink: 9.229
Orthoclase feldspar, Potassium feldspar, KAlSi3O8 (Geology)
Orthophosphoric acid, H3PO4, phosphoric acid
Oscillating reaction, Potassium bromate with propanedioic acid, double autocatalytic reaction: 17.3.7
Osmium, Os
Osmosis, osmotic pressure, reverse osmosis: 9.14.0
Osteoarthritis: 9.238
OTO, Tolidine, C14H16N2 (swimming pools)
Ouabain, C29H24O12
Ouabagenin, C23H34O8, cardenolide
Oudeman's insect fixing fluid, Prepare: 4.11
Ouzo effect: 7.6.01
Oven temperatures: 6.14.0
See: Ovens (Commercial)
Overalls (Safety)
Oxacillin, penicillinase-resistant β-lactam antibiotic, replacing methicillin
Oxalate ion: C2O42-, sodium oxalate: Na2C2O4
Oxalate (oxalato), [O-C(=O)-C(=O)-O]2-, bidentate ligand
Oxalates, hazards: 3.7.11
Oxalates, Tests for oxalates: 12.11.5.14
Oxalic acid, H2C2O4, ethanedioic acid
OXD: react with substances to produce great heat
Oxidants
Oxidants, List of oxidants: 1.20
Oxidation and reduction
Oxidation reactions: 12.2.1
Oxides, Reactions of oxides: 12.17.0
Oxidizing agents
Oxidizing agents, Tests for oxidizing agents
Oxidizing, Hazard classifications: 15.1.0
Oximes: 16.2.4.6
Oxonium ion, Hydronium ion, hydroxonium ion, H3O+
Oxyacids, oxoacids: 13.3.6
Oxyacetylene welding (oxy-acetylene welding): 16.4.6.1
Oxycodone, LSD, Lysergic acid diethylamide: 11.11.9.1
Oxygen, O2
Oxymatrine, C15H24N2O2
Oxymuriatic acid, former name for hydrochloric acid or chlorine in solution, (also: "dephlogistonated marine acid"!)
Oxytocin.
Ozone.

Octane
Octane, C8H18, n-octane, colourless, normal octane, Harmful, stable but highly flammable
16.6.8.0 Octane (C8H18), Octane number
iso-Octane
n-Octane
Cracking: 7.9.15.1
Spark plug, pre-ignition: 32.5.5.5.1.

Odour
Odour, chemical vapours and smelling chemicals: 3.4.8.

Oils
Canola (Brassica species), Brassicaceae.
Edible oils, Composition of edible oils: 19.2.11 (Table)
Essential oils, volatile oils, ethereal oils: 16.6.1
Fixed oils, non-volatile oils: 16.6.2
List of oils
List of essential oils: 16.6.1a
List of fixed oils: 16.6.2a
List of vegetable oils: 16.6.3a
Plant oils, essential oils, fixed oils, vegetable oils: 16.6.0
Vegetable oils: 16.6.3

List of oils
Almond oil, Almond butter: 16.3.6.18
Aniline oil, C6H5NH2, phenylamine, aminobenzene,
poisonous, used to make dyes, plastics, medicines, Not permitted in schools
Camphor oil, Prepare: 19.6.7
Castor oil, ricinoleic acid: 16.3.6.4
Clove oil, eugenol: 16.3.6.9
Coconut oil: 17.0
Crude oil, Fractional distillation of crude oil: 16.1.12
Eucalyptus oil
Evening primrose oil.
Fish oils: 19.2.1.12
Goanna oil, goanna fat, lizard-like Varanus sp, (lubricant, liniment, arthritis, muscle soreness)
Lavender oil
Lemon oil, lemon juice
Linseed oil
Neatsfoot oil
Neem oil, Azadirachta indica, Meliaceae
Oil and water, Hydrophilic, hydrophobic
Oil drilling additives
Oil molecule, Size of oil molecule: 3.3.2
Oil red stain: 3.32
Oil of vitriol, sulfuric acid: 12.18.5
Oil of wintergreen, methyl salicylate
Oil shale and fracking (hydraulic fracturing): 35.23.10
Oil sprays, white oils, pesticides: 16.9.0 (Agriculture)
Olive oil
Paraffin oil, kerosene
Peanut oil, Solvent extraction of oil from peanuts: 10.12.1 (groundnuts)
Pear oil, Prepare amyl acetate: 16.5.6
Penetrating oil, e.g. WD-40: 10.6.3.1
Pennyroyal oil (Poisonous)
Petroleum jelly, "Vaseline", white paraffin
Petroleum, Distil crude oil and collect the fractions: 10.6.3
Petroleum (crude oil and gas): 35.23.4
Prepare soap with fats or oils: 12.9.1
Prepare soap with vegetable oils: 12.12.2
Salad oil
Solutions, infusion, decoction, tincture: 5.04
Tea tree oil
Tests for fats and oils: 9.137
Tung oil
Vanilla oil (See: 3.)
Vegetable oils: 16.6.3.

Oil drilling additives
1. Bentonite and barite
2. Calcium chloride
3. Sulfonated asphalt
4. Xanthan gum
5. Polyacrylamide (PAM)
6. Polyanionic cellulose (PAC)
7. Sodium carboxyethylcelulose (CMC)
8. Carboxymethyl starch sodium (CMS).

Oil of wintergreen
Oil of wintergreen, methyl salicylate, strong characteristic odour
Gaultheria procumbens (sweet birch tree), wintergreen, oil of wintergreen, snow berry, tea berry, checkerberry, aromatic
wintergreen, gaultheria oil, Ericaceae
Prepare methyl salicylate, oil of wintergreen: 16.5.5
Salicylate intolerance: 19.2.1
Aspirin and analgesics, Panadol, Tylenol: 11.11.6.

Oleic acid, C17H33COOH
See diagram 19.2.1: Oleic acid, stearic acid, linoleic acid (cis and trans)
Oleic acid, cis-octadec-9-enoic acid, cis-09-octodecanoic acid, mono-unsaturated fatty acid, monounsaturated omega-9 fatty acid
Oleic acid, mono-unsaturated fatty acid, CH3(CH2)7CH=CH(CH2)7COOH, colourless viscous liquid, m.p. 14oC
Models, biochemistry, Oleic acid, C18H34O2, 1 molecule (photograph), "Scientrific" (commercial website)
Models Oleic Acid, "Scientrific" (commercial)
Fats in food: 3.90
Fats in animals and plants: 19.2.1.1
Olive oil
Size of an oil molecule: 3.3.2
Soaps and synthetic detergents, "syndets": 12.12.0.

Oleic acid has been found to increase good cholesterol and lower bad cholesterol.
Proponents of olive oil claim that in countries where oleic acid istheprinciple fat in the diet the people have the lowest incidence of
heart disease and strokes and the longest life span and that only oliveoil is high in mono-unsaturated fats and low in both
polyunsaturated and saturated fats.
However, it seems that people living in different countries where thecomponents of fats in their diets are almost identical may have very
different rates of the incidence of cancer, so perhaps other factors are involved.
Olives are a remarkable source of antioxidant and anti-inflammatory phytonutrients.
Most prominent are two simple phenols (tyrosol and hydroxytyrosol) andseveral terpenes (especially oleuropein, erythrodiol, uvaol,
oleanolic acid, elenoic acidand ligstroside).
Flavonoids (including apigenin, luteolin, cyanidins, and peonidins), are typically provided in valuable amounts by olives, as are
hydroxycinnamic acids like caffeic acid, cinnamic acid, ferulic acid, and coumaric acid.
The phytonutrient content of olives depends upon olive variety, stage of maturation, and post-harvest treatment and geography because
olives grown in cooler climates are said to contain moreoleic acid.
Olives are a very good source of monounsaturated fat (in the form ofoleicacid) and a good source of iron, copper, and dietary fibre.

Oranges (fruit)
Hesperidin, Treatment for capillary fragility, Citrus sp. (e.g.oranges)
Flavonoids, plant polyphenols: 16.3.4.2
Prepare esters: 16.5.3
Sweet orange (Citrus x sinensis)
Use oranges, studded with cloves, as pomanders to remove musty smells from wardrobes.

Organic chemistry
See: Organic Chemistry, Biochemistry, (Commercial)
Chemical changes, heat organic substances: 7.1.2
Organic builders in washing powders: 12.12.03.2b
Organic chemistry, Carbon, C: 16.1.0
Organic chemistry terms: 16.9.0
Organic liquid residues: 3.4.12.5
Organic peroxides, Hazards: Class 5.2: 15.1.0
Chemical changes, heat organic substances:7.1.2
Properties of elements: 7.0
Storing organic chemicals: 3.4.13.6
Tests for organic acids and alcohols: 16.4.1.0
Tests for organic compounds: 16.4.5.0.

Osmium, Os
Osmium
, Os (Greek osmē smell, refers to strong irritating smell of poisonous osmium tetroxide).
Osmium is a silver-blue, very rare, very hard element, and possible the densest element, if not Iridium.
It was discovered in 1803 by Smithson Tennant, England.
Osmium tetroxide, OsO4, osmic acid, osmium oxide, osmium (VIII) oxide, solid, pungent unpleasant odour,
It is extremely Toxic.
Not permitted in schools.
Osmium was used in gramophone needles and fountain pen nibs, e.g. Osmiroid, because of extreme hardness and resistance to
corrosion.
Osmium, melting point 3, 054oC, was formerly used in electric light filaments, e.g. "Osram", but was replaced by tungsten, melting
point, 3, 407oC.
Used in jewellery plating.
Osmium tetroxide vapour forms black deposits with oil, so is used infingerprinting.

Oxalic acid, H2C2O4, ethanedioic acid
Decomposition of oxalic acid: 3.30.10
Oxalates hazards: 3.7.11
Oxalic acidwith potassium manganate (VII), autocatalysis: 17.3.3
Prepare oxalic acid, ionization reaction: 16.4.3
Prepare solutions of known concentration: 5.4.0
Tests for antimonates, borates, oxalates: 12.11.5.2a
Tests for oxalates: 12.11.5.14
Thermal decomposition of oxalic acid: 8.2.4.

Oxalic acid, H2C2O4, C2H2O4.2H2O, HO2CCOOH, (COOH)2, HOOCCOOH, ethanedioic acid, oxalic acid dihydrate, odourless.
white solid, sinks in water and mixes with it, Toxic, strong dicarboxylic acid occurs in many plants, e.g. rhubarb.
Produced in humans by metabolism of glyoxylic acid or ascorbic acid, then excreted in the urine.
Oxalic acid, Solution < 5%, Not hazardous (analytical reagent, reducing agent, used to standardize sodium hydroxide solution.)
Oxalic acid with concentrated sulfuric acid forms carbon monoxide.
Oxalic acid dihydrate, HO2CCO2H.2H2O, white, odourless, monoclinic crystals or granules, r.d. 1.62, m.p. 101oC - 102oC,
sublimes easily above 100oC, decomposed by heat, occurs in rhubarb and many plants.
Ammonium oxalate, C2H8N2O4, (NH4)2C2O4), occurs in kidney stones, guano.
Oxalic acid common names: Non-chlorine bleach powder (cleanser used in bars), Low cost: purchase from hardware stores as wood bleach.
See diagram: Oxalic acid

Oxygen, O2
See: Oxygen Elements, Compounds, (Commercial)
Oxygen Table of Elements
Oxygen gas
Oxygen Experiments
3.48 Acid rain and nitrogen oxides, NOx
3.36 Carbon dioxide and photosynthesis
7.1.0 Chemical changes and physical changes
37.42.1 Composition of the atmosphere and greenhouse gases
3.30.4 Decomposition of nitrates
3.30.5 Decomposition of oxides
Density, Table 1.0.0 Molecular weight, Density
7.9.28 Fuel cell
4.229.1 Mountain sickness and hyperventilation
12.17.1.1 Oxides and the periodic table
16.4.6.1 Oxyacetylene welding (oxy-acetylene welding)
18.3.2 Oxygen content of water, dissolvedoxygen, DO
12.2.6.2 Oxygen with sulfur dioxide, (redox reaction)
19.4.22 Packaging gases, propellants, food additives.

Oxygen Experiments
13.3.4 Burn magnesium ribbon inoxygen
13.3.3 Burn steel wool and burn iron filings
13.3.2 Burn sulfur in oxygen
3.30.11 Decomposition of chlorates, potassium chlorate
3.30.17 Decomposition of manganates, potassium permanganate
12.3.11.0 Dilute nitric acid withcopper
15.5.12.1 Electrolysis of dilute sodium chloride solution 1
15.5.12.2 Electrolysis of dilute sodium chloride solution 2
8.2.0 Heat metals in air to form oxides
12.17.2.2 Heat metals with oxides of another metal (competition for oxygen)
12.12.5 Hydrogen peroxide acts asa reducing agent
3.49.2 Hydrogen peroxide concentration and storage
12.12.4 Hydrogen peroxide reacts as an oxidizing agent
13.1.6 Molar volume of oxygen prepared with hydrogen peroxide
15.3.4 Need for oxygen for rusting
12.17.1.1 Oxides and the periodic table
13.3.6 Oxyacids, oxoacids
3.52.2 Oxygen gas combines with ironduring rusting
8.6.2 Oxygen gas is necessary for combustion
9.237 Oxygen content of inhaled and exhaled air
12.12.3 Prepare hydrogen peroxide solution
12.12.0 Prepare oxides
12.12.1 Prepare oxygen gas
12.11.1 Prepare verdigris with copperand vinegar (See 1.)
13.3.6 Reactions of magnesium oxide
3.73 Reactions of sodium withwater
12.2.6.0 Redox reactions (oxidation-reduction reactions, electron transfer reactions)
15.3.3 Rusting of steel wool
18.3.3 Tests for dissolved oxygen, titration
6.6.7 Tests for oxygen absorption during plant respiration
3.49.1 Tests for oxygen gas
15.5.12 Tests for oxygen gas, electrolysis.

12.12.0 Prepare oxides
Heat metals in air to form oxides: 8.2.0
Prepare oxides by direct oxidation: 12.12.1
Prepare oxides by indirect oxidation: 12.12.2.

12.12.1 Prepare oxygen gas
Decomposition of manganates: 3.30.17
Prepare oxygen gas with bleach: 3.49.3
Prepare oxygen gas with hydrogen peroxide: 3.49.0
Prepare oxygen gas with potassium chlorate and manganese dioxide, Dangerous experiment!
Prepare oxygen gas with potassium manganate (VII): 3.49.4
Prepare oxygen absorbent: 13.3.5.

Oxygen gas
Oxygen, O (French oxygène, acidifying, oxygen was thought tobe in all acids).
Oxygen gas, O2, is a non-metal colourless and odourless gasat room temperature and pressure, 20.95% of the air, 47% of the earth's
crust, identified by lighting a glowing splint, supports combustion and is necessary for respiration.
Prepared in the laboratory by decomposition of hydrogen peroxide with MnO2 catalyst, but manufactured by distillation of liquid air.
It is the most abundant element, 50% of mass of rocks in earth's crust.
It reacts with metals to form basic oxides, and reacts with non-metals to form acidic oxides.
Oxygen gas is stored compressed in cylinders for oxy-acetylene welding.
Liquid oxygen, refrigerated oxygen, may explode with flammable or combustiblesubstances, and may cause frostbite (cold burns).
So use ventilated gloves!
Atomic number: 8, Relative atomic mass: 15.9994, r.d. 1.15(90 K), m.p.= -218oC, b.p. = -183oC.
Specific heat capacity: 916 J kg-1 K-1.

Oxidation and reduction
Oxidation, in a cell, oxidation occurs at the anode and reduction occursat the cathode
Oxidation and reduction, redox reactions: 15.2.0
Oxidation, air pressure: 15.3.8
Oxidation and air pressure, steel wool: 4.241
Oxidation of glucose, blue bottle: 16.3.7.2
Oxidation of glycerine: 12.7.6
Oxidation of iron: 6.23 (Soils)
Oxidation of methanol to methanal: 16.3.2.8
Oxidation reactions, Prepare: 16.1.03
Catalytic oxidation of ammonia forms nitrogen monoxide: 13.6.6.1
Disproportionation
Tests for oxidase and peroxidase: 9.3.11
Tests for oxidation of glucose: 16.3.7.2
Tests for oxidizing agents: 15.2.8.

Oxides, O2-
Acids and metal oxides, insoluble base, prepare salts: 2.2
Carbon dioxide, CO2: 3.34.0
Carbon dioxide, Prepare carbon dioxide: 3.34.1
Carbon monoxide, C≡O (note triple bond): 16.4.5
Decomposition of oxides: 3.30.5
Nitrogen dioxide, NO2: 13.1.23
Nitrogen monoxide (nitric oxide), NO: 13.1.25
Nitrogen oxides, Acid rain, NOx: 3.48
Nitrous oxide (dinitrogen monoxide), N2O: 13.1.27
Oxides, thermal decomposition: 3.30.5
Prepare oxides, heat metals in air to form oxides: 8.2.0
Prepare oxides by direct oxidation: 12.12.1
Prepare oxides by indirect oxidation: 12.12.2
Peroxides, hazards: 3.7.13
Reactions of oxides: 12.17.0
Reduce iron (III) chloride with sulfur dioxide: 3.51.3
Separate metals, reduce metal oxides, ores: 10.10.0
Sulfur dioxide, SO2: 13.1.35.

Oxidizing agents
Bromine as an oxidizing agent: 15.2.2.1
Chlorine as an oxidizing agent: 15.2.2
Concentrated nitric acid as an oxidizing agent: 15.2.5
Hydrogen peroxide as an oxidizing agent: 15.2.7
Iron (II) sulfate oxidation to iron (III) sulfate: 12.1.3
Nitrous acid, oxidizing / reducing agent: 15.2.5.1
Oxidizers: 18.7.51 (Swimming pools)
Oxidizing agents and reducing agents: 15.5.0
Oxidizing agents: 18.7.11 (Swimming pools)
Oxygen as an oxidizing agent: 15.2.1
Potassium chlorate, oxidizing agent: 15.2.13
Potassium dichromate, oxidizing agent: 15.2.3
Potassium persulfate, oxidizing agent: 15.2.13
Storing oxidizing agents: 3.4.13.7
Sulfuric acid, oxidizing agent: 15.2.6.

Tests for oxidizing agents
Tests oxidizing agents, iron (II) to iron (III): 15.2.8
Tests oxidizing agents, Fe and copper sulfate: 15.2.9
Tests oxidizing agents, Zn and copper sulfate: 15.2.10.

3.49.0 Prepare oxygen with hydrogen peroxide
See diagram 3.2.35: Prepare oxygen, a holder for burning substances
Oxygen is a colourless odourless diatomic gas that supports combustion and is essential for aerobic respiration.
Oxygen reacts with metals to form basic oxides.
Oxygen reacts with non-metals to form acidic oxides.
Oxygen does not change the colour of moist litmus.

1. The safest method to prepare oxygen is by decomposition of hydrogen peroxide solution.
Hydrogen peroxide may be sold in two strengths 10 volumes (3% w/w) and20 volumes (6% w/w).
Pour some 20 volumes (vols) hydrogen peroxide into a test-tube containing manganese (IV) oxide granules as a catalyst and some water.
Collect oxygen in receiver test-tubes over water and apply stoppers to the test-tubes.
Test for oxygen with the glowing splint test.
2H2O2 (aq) --> O2 (g) + 2H2O (l) [with MnO2 as catalyst]
Store test-tubes of oxygen in a test-tube rack and remove the stoppers just before inserting the burning element.
This experiment may not be safe because the decomposition reaction occurs quickly and water vapour shoots out of the container.
Safety can be improved by using 44 micronmetre (micron), particle size manganese dioxide instead of the smaller 10 micrometre particle size.

2. Put 1 cm depth of hydrogen peroxide solution in a test-tube.
Add a drop of iron sulfate solution (FeSO4.7H2O, ferrous sulfate, green vitriol).
The contents froth vigorously.
Test for oxygen with the glowing splint test.

3. Pour dilute hydrogen peroxide into a measuring cylinder.
Add drops of detergent.
Add manganese (IV) oxide (manganese dioxide) powder as a catalyst
The reaction forms oxygen as a foam of bubbles.
Use the oxygen foam for combustion experiments with burning twine, burningiron wire and burning magnesium.
Test the gas in the space above the liquid.

4. To 3 mL of 6% hydrogen peroxide solution, add:
1. Powdered manganese dioxide, MnO2, as a catalyst
2. 0.5 mL of 1 M FeCl3,
3. 20 grains of active dry yeast.
Test the oxygen formed by these catalytic reactions with a glowing splint.
2H2O2 --> 2H2O + O2 (g).

5. Pour some 20 volumes (vols) hydrogen peroxide into a test-tube containing manganese (IV) oxide granules as catalyst
Collect oxygen in receiver test-tubes over water and apply stoppers to the test-tubes.
Store test-tubes in a test-tube rack and remove the stoppers just before inserting the burning element.
2H2O2 (aq) --> O2 (g) + 2H2O (l) [with MnO2 as catalyst].

6. Put 1 cm depth of hydrogen peroxide solution in a test-tube.
Add a drop of iron sulfate solution (FeSO4.7H2O, ferrous sulfate, green vitriol).
The contents froth vigorously.
Test for oxygen with the glowing splint test.

7. Prepare oxygen with potassium manganate (VII).
Wear eye protection. Put a two fingers depth of potassium manganate (VII) in a Pyrex test-tube.
To control "spitting" put a loose plug of ceramic wool in the mouth of the test-tube.
Heat the test-tube slowly and hold a glowing splint over the mouth of the test-tube to detect oxygen.
Hold a glowing splint above the top of the test-tube while continuing the heating.
The glowing splint relights.

8. Use a hose to bubble hydrogen through detergent.
Separate a handful of suds and use a lighted match to ignite the hydrogen
9. React aluminium foil with acid in a flask.
Run water over the outside of the flask when the reaction becomes toovigorous to prevent it from overheating.

3.49.4 Prepare oxygen gas with potassium manganate (VII)
Wear eye protection.
Put a two fingers depth of solid potassium manganate (VII) in a Pyrex test-tube.
To control "spitting" put a loose plug of ceramic wool in the mouth of the test-tube.
Heat the test-tube slowly and hold a glowing splint over the mouth ofthe test-tube to detect oxygen.
Collect the gases over water.
Hold a glowing splint above the top of the test-tube while continuing the heating.
The glowing splint relights.
2KMnO4 --> MnO2 + O2.

8. Use a hose to bubble hydrogen through detergent.
Separate a handful of suds and use a lighted match to ignite the hydrogen.

9. React aluminium foil with acid in a flask.
Run water over the outside of the flask when the reaction becomes too vigorous to prevent it from overheating.

3.49.1 Tests for oxygen gas
1. Glowing splint test
Light a splint of wood.
Blow out the flame then hold the glowing splint in the test-tube full of oxygen.
The splint relights.

2. Steel wool test
Collect oxygen in test-tubes with stoppers.
Use an L-shaped piece of nichrome wire with a shield to fit on the top to protect your hand.
Fix steel wool into a loop in the lower end of the Nichrome wire.
Heat the steel wool to red heat in a Bunsen burner flame then insert it quickly into a test-tube of oxygen.
The steel wool burns with bright sparkles to form black grey iron oxide, Fe3O4 (FeO.Fe2O3).
Sprinkle iron filings into a Bunsen burner flame.
A shower of sparks occurs, as in some fireworks.
6Fe + 4O2 --> 2Fe3O4.

3. Charcoal test
Fix charcoal into the loop in the lower end of the Nichrome wire or use a combustion spoon.
Heat the charcoal in a Bunsen burner flame until it has a red glow, then quickly insert it into a test-tube of oxygen.
The charcoal glows much more.
C + O2 --> CO2 (g).

4. Magnesium ribbon test
Be careful! Do NOT look at the bright flame.
Wrap a 3 cm piece of magnesium ribbon around the loop at the end of a wire.
Ignite it in a Bunsen burner and put it quickly in the oxygen.
Magnesium burns with a very bright flame.
2Mg + O2 --> MgO (s).

3.49.3 Prepare oxygen with bleach
Prepare oxygen with household bleach, sodium hypochlorite, or bleaching powder
Liquid household bleach is usually 5% sodium hypochlorite, NaOCl.
Bleach is manufactured by passing chlorine through sodium
hydroxide solution until neutral pH, then diluted to 5%.
1. Heat 1 cm depth of bleaching powder in a dry test-tube.
2. Put 1 cm depth of concentrated household bleach solution (NaOCl, bleaching fluid) or bleaching powder solution in a test-tube and
add drops of concentrated cobalt chloride solution.
A black precipitate forms.
Heat the test-tube until frothing starts.
3. Add 1 cm depth of bleaching powder to 2 cm depth of water in a test-tube.
Heat the test-tube.
No oxygen forms.
Add drops of copper (II) sulfate solution and heat again.
Little oxygen forms.
Add drops of iron sulfate solution (FeSO4.7H2O, ferrous sulfate, green vitriol).
The solution effervesces strongly because much oxygen forms.
4. Put 2 cm of bleaching fluid in a test-tube and add a crystal of cobalt chloride.
The contents of the test-tube turn black.
Heat the test-tube over a flame.
Effervescence begins and oxygen forms.
Test for oxygen by putting a glowing wood splint into the mouth of the test-tube.

Oxytocin, C43H66N12O12S2,
nonapeptide hormone released from posterior pituitary gland, acts on smooth muscle cells, causing uterine contractions and milk ejection.
Recombinant oxytocin is a synthetic cyclic peptide form of the naturally occurring hormone used to stimulate uterine and mammary glands
smooth muscle contractions, causing lactation.

Carbetocin, C45H69N11O12S,
drug used to control postpartum hemorrhage, bleeding after giving birth, analogue of oxytocin and with similar action causing contraction of the uterus.

Ozone
See: Ozone Elements, Compounds, (Commercial)
Ozone, O3 (ozone, Greek: ozein, to smell), Highly toxic gas with pungent odour.
Formerly called "electric oxygen".
Composition of the atmosphere: 37.42.1
Density, Ozone (Table)
Ozonator: 18.7.52 (swimming pools)
Ozone and photochemical smog: 3.50.1
Prepare ozone gas: 3.50
Solar ultraviolet radiation and skin cancer: 37.34
Table 12.19.5.0, RODP =therelative ozone depletion potential (RODP).

3.50 Prepare ozone gas
See diagram 3.50: Prepare ozone
Ozone, O3, Highly toxic, pale blue gas, with a distinct pungentodour, like weak chlorine.
It is a powerful oxidizing agent that irritates the lungs.
Ozone is formed in the atmosphere by the action of ultraviolet light with oxygen to form the ozone layer.
You may smell ozone in underground train tunnels if electric sparks hadoccurred between the power rail and the electrical pickup shoe.
Ozone may be smelt around photocopiers, e.g. Rank Xerox, and laser printers, if they are not well ventilated.
However, manufacturers of these products claim that ozone can be smeltin concentrations as little as one part in 500, 000, while the
threshold limit value for short term exposure is 0.3 parts per million.
Small concentrations of ozone are used as an air freshener / sanitizer in public facilities and rest rooms to destroy atmospheric germs
and odours.
Ozone was discovered by Christian Schönbein (1799-1868) who noticed an unusual smell around electrical experiments.
So he named the gas using the Greek word: to smell, ozein.
Previously it was thought that the seaside smelt of ozone, but this smellprobably comes from of rotting seaweed.
Oaks and willows are said to emit ozone to deter vegetation near them.
The ozone layer is in the stratosphere, 20 to 40 km above the Earth.
It absorbs some of the ultraviolet light that causes skin cancer.
Ozone is produced with oxides of nitrogen by reactions of car exhaust gases with unburned fuel and sunlight to produce
photochemical smog.
After a thunderstorm, the refreshing smell is ozone and nitrogen oxides.

1. Prepare ozone in the laboratory using a high voltage induction coil, spark coil (an ozonizer).
However, the experiment is dangerous.
Do not attempt it in a school laboratory.
3O2 (g) --> 2O3 (g)
2. Use electrolysis of 4 M sulfuric acid with carbon anodes.
Pass 12 volts through the circuit and note the smell of ozone at theanode.
3. In the upper stratosphere, ozone forms when ultraviolet (UV) light splits an oxygen gas molecule, O2, into two atoms of oxygen, O.
O2 + UV --> O + O.
The oxygen atoms can react with other oxygen molecules to produce ozonethat sinks down to the lower stratosphere, between 20
and 40 km above the Earth.
O + O2 --> O3
Also, the oxygen atoms can react with ozone to produce oxygen molecules again.
O + O3 --> O2 + O2
When ozone absorbs UV light, the ozone breaks into an oxygen molecule and an oxygen atom again.
O3 + UV --> O2 + O.

3.50.1 Ozone and photochemical smog
A nitrogen dioxide molecule can be dissociated by absorbing photon, hv, of sunlight.
NO2 (g) + hv --> NO (g) + O (g) [reactive oxygen atom]
O (g) + O2 (g) --> O3 (g)
2NO (g) + O2 (g) --> 2NO2 (g).

1. Prepare ozone in the laboratory using a high voltage induction coil, spark coil (an ozonizer).
However, the experiment is dangerous.
Do not attempt it in a school laboratory.
3O2 (g) --> 2O3 (g).

2. Use electrolysis of 4 M sulfuric acid with carbon anodes.
Pass 12 volts through the circuit and note the smell of ozone at the anode.

3. In the upper stratosphere, ozone forms when ultraviolet(UV) light splits an oxygen gas molecule, O2, into two atoms of oxygen, O.
O2 + UV --> O + O.
The oxygen atoms can react with other oxygen molecules to produce ozone that sinks down to the lower stratosphere, between 20
and 40 km above the Earth.
O + O2 --> O3
Also, the oxygen atoms can react with ozone to produce oxygen molecules again.
O + O3 --> O2 + O2
When ozone absorbs UV light, the ozone breaks into an oxygen molecule and an oxygen atom again.
O3 + UV --> O2 + O: 12.12.8

13.3.2 Burn sulfur in oxygen
Dip a wire loop into sulfur powder. Ignite the sulfur in a burner flame, and then put it into a test-tube of oxygen.
The sulfur burns with a bright blue flame to form the colourless gassulfur dioxide.
S (s) + O2 (g) --> SO2
sulfur + oxygen --> sulfur dioxide
Some sulfur trioxide may also form in this reaction.

13.3.3 Burn steel wool and burn iron filings
1. Collect oxygen in test-tubes with stoppers.
Store test-tubes in a test-tube rack and remove the stoppers just beforeinserting the burning element.
Fasten steel wool to wire.
Heat the steel wool in a burner flame.
Put it into a test-tube of oxygen.
The steel wool burns with bright sparkles to form black-grey iron oxide.
4 Fe (s) + 3 O2 (g) --> 2 Fe2O3 (s)
iron + oxygen --> iron oxide
2. Repeat the experiment by placing iron filings in a sieve and shaking it over a Bunsen burner flame.
A shower of sparks occurs as in some fireworks.

13.3.4 Burn magnesium ribbon
Magnesium reacts easily with oxygen in the air to form a protective coating of magnesium oxide.
Magnesium burns in oxygen with an intense white flame that can hurt theeyes.
So it has been used in fireworks and photographic flashlights.
1. When a strip of magnesium burning in air is dipped into a gas jarof oxygen, it burns with a more intense white flame to form a
white powder, magnesium oxide
2. Mg (s) + O2 (g) --> 2MgO (s) + energy
magnesium + oxygen --> magnesium oxide
The magnesium has been oxidized (oxidation number increases), and theoxygen has been reduced (oxidation number decreased).
The ionic compound magnesium oxide is a basic oxide, which dissolves slightly in water to form an alkaline solution about pH10.

2. Wrap a 3 cm piece of magnesium ribbon around the loop at the end of a wire. Ignite it in a burner and put it quickly in the oxygen.
Magnesium burns with a very bright flame.
BE CAREFUL!
Do NOT look directly at the flame because its brightness can cause injuryto eyes.
The white smoke is magnesium oxide. Its toxicity is low, but inhalation should be avoided.
Put the ash on a watch glass and add 3 mL of deionized water to wet theash thoroughly, and leave it lying in a small pool of water.
Add one small drop of phenolphthalein solution and leave to stand fortwo minutes.
Magnesium oxide has a low solubility in water, so there is no visible evidence that any of the solid has dissolved.
Add one drop of dilute hydrochloric acid solution, and leave to stand until the solution around the solid ash will turn pink, showing
that the solution has become alkaline.
This is the evidence that some magnesium oxide has dissolved.
Oxide ions in the solid react with water to form aqueous hydroxide ions.
When no further change occurs, add a second drop of dilute hydrochloric acid.
The pink colour disappears almost instantly, showing that the hydroxide ions have been neutralized very quickly, and replaced by an
excess of hydrogen ions.
During the next 2 to 15 minutes, depending on the size and concentration of the drop of acid added, the mixture changes slowly back
to pink as the excess acid is being neutralized slowly by solid magnesium oxide, followed by slow dissolving of remaining magnesium
oxide to make the solution.
When no more changes occur, add a second small drop of dilute hydrochloric acid.
The same cycle of discharge and reappearance of pink colour can be repeatedfor as long as any solid magnesium oxide remains.

3. Burn 6 cm of magnesium ribbon in the air over a piece of paper.
Add water to the remaining white magnesium oxide solid, add water inabeaker, boil and test with red litmus paper.
The litmus paper slowly turns blue showing the magnesium oxide solution to be weakly alkaline.

13.3.5 Prepare oxygen absorbent
Dissolve 300 g of ammonium chloride in 1 litre of water and add 1 litreof concentrated ammonia solution.
Shake the solution.
Pass the gas through the solution after adding half the volume of copperturnings.

13.3.6 Oxyacids, oxoacids
Oxy-acid, oxyacid, any acid containing oxygen (differentfrom oxo carboxylic acids)
Oxyacid, has an O bonded to a H and one or more other elements
The common examples of oxyacids are acetic acid (ethanoic acid) (CH3COOH) | boric acid (boracic acid) (H3BO3) (not strictly
an oxyacid)| carbonic acid (H2CO3) | nitric acid (HNO3) | nitrous acid (HNO2) | phosphoric acid (H3PO4) | sulfuric acid (H2SO4) |
sulfurous acid (H2SO3) |.
The halogen oxyacids include chloric acid (HClO3) | chlorous acid (HClO2), weak unstable acid, | hypochlorous acid (HClO) |
perchloric acid (HClO4) |.
The following carboxylic acids (RCOOH), are oxyacids: acetic acid (CH3COOH)| benzoic acid (benzene carboxylic acid)
(C6H5COOH) | chloroacetic acid (CH2ClCOOH) | dichloroacetic acid (CHCl2COOH) | formic acid (methanoic acid), (HCOOH) |
oxalic acid (ethanedioic acid) (COOH)2 | trichloroacetic acid (trichlorethanoic acid) (CCl3COOH) | trifluoroacetic acid (CF3COOH).