Gases

Hold lit splint over mouth of test tube
Squeaky pop indicates positive result
H2 + O2 --> H2O

Put glowing splint into tube of gas
Splint relighting indicates positive result
Combustion of the wood in the splint

Bubble gas through limewater
Turns cloudy if CO2 is present
Ca(OH)2 + CO2 --> CaCO3 + H2O
Insoluble calcium carbonate produced forming white suspension

Put damp blue litmus paper in test tube of gas
Turns whiteleaches if test is positive

Put damp red litmus paper in a test tube of gas
Turns blue if test is positive
NH3 is an alkaline gas
NH3 + H2O --> NH4OH

Add white anhydrous copper (II) sulfate which turns from white to blue in presence of water
Anhydrous copper (II) sulfate + water --> hydrated copper (II) sulfate
CuSO4 + 5H2O --> CuSO4.5H2O

Clean a platinum wire loop with dilute HCl and hold it in flame
Once it burns without any colour, dip it in sample
Put it back in clear blue part of flame and observe colour
Lithium (Li+) has a red flame
Sodium (Na+) has a yellow flame
Potassium (K+) has a lilac flame
Calcium (Ca2+) has an orange-red flame
Copper ions (Cu2+) have a blue-green flame

Add a few drops of sodium hydroxide to your mystery compound
Copper (II) forms a gelatinous blue precipitate
Iron (II) forms a gelatinous green precipitate
Iron (III) forms a gelatinous reddish brown precipitate
eg Cu2+ + 2OH- --> Cu(OH)2

Add sodium hydroxide to mystery solution
Use yellow flame (because ammonium is explosive)
If ammonium ions are present, ammonia gas will be released
Red litmus will turn blue in the presence of ammonia

Add dilute HCl to test sample
If carbonates (CO3 2-) are present then CO2 will be released
Test for CO2 using limewater
carbonate + acid --> carbon dioxide + water

Add dilute HCl, followed by barium chloride solution (BaCl2) to test sample
If sulfate ions were present in the original compound, then a white precipitate of barium sulfate will be produced
HCl added to get rid of any traces of carbonate or sulfite ions before you do the test as they would also produce a precipitate

Add dilute nitric acid (HNO3) followed by silver nitrate solution (AgNO3)
Nitric acid added to get rid of carbonate or sulfite ions before the test
A chloride ion gives a white precipitate of silver chloride
A bromide ion gives a cream precipitate of silver bromide
An iodide ion gives a yellow precipitate of silver iodide

78%

21%

0.9%

0.04%

Rusting is an example of slow oxidation (where iron reacts with water and oxygen to form hydrated iron oxide)
Combustion is an example of faster oxidation
Oxidation is the gain of oxygen or loss of electrons
When we oxidise metals we form alkaline oxides
When we oxidise non-metals we form acidic oxides

Starts to glow, still burning
Forms solution of pH 3

Blue flame
Forms solution of pH 1
Produces sulfur dioxide

Burns with a bright, white flame
White powder that forms is magnesium oxide
Forms a slightly alkaline solution

Put iron wool soaked in aceitic acid (acid will catalyse the reaction) in a measuring cylinder which is inverted in a beaker of water
Over time the level of the water will rise because the iron reacts with oxygen in air

Place phosphorous in glass tube and attach syringes at either end
Heat the phosphorous and pass air over it using the syringes (the phosphorous in the air will react to form phosphorous oxide)
As it reacts, the volume of air in the syringes will decrease

(start volume - final volume/ start volume) x 100

Greenhouse gas
Acts like a natural insulating layer that absorbs most of the heat that would normally be radiated out into space and re-radiates it back towards Earth
Deforestation means that there are fewer trees to remove CO2 from the atmosphere via photosynthesis
Burning fossil fuels releases the carbon that was locked up in fossil fuels as carbon dioxide

Thermal decomposition is when a substance breaks down into smaller substances when heated
If you heat a metal carbonate, you get carbon dioxide and a metal oxide
Copper (II) carbonate is a green powder that will easily decompose to form carbon dioxide and copper (II) oxide
CuCO3 --> CuO + CO2