Chemicl Tests And Reactions

Question 1

A reaction is occurring when

Answer 1

Bubbles
Change colour
Fizzing
Precipitate formed

Question 2

Reactions of acid

Answer 2

Acid + metal= salt +hydrogen 
Acid + base = salt +water
Acid + Alkali = salt +water 
Acid + metal carbonate= salt +water+ carbon dioxide
Acid + ammonia = ammonium salt

Question 3

Displacement reaction

Answer 3

A more reactive element will displace a less reactive element from its compounds

Question 4

Hydrogen test

Answer 4

Squeaky pop

Lit splint at top of test tube and pop heard if hydrogen

Question 5

Oxygen test

Answer 5

Relight a glowing splint

Question 6

Carbon dioxide test

Answer 6

Bubble gas through lime water and the limewater will turn cloudy/milky if the gas is carbon dioxide due to the presence of insolvable calcium carbonate being formed

Question 7

Ion tests

Answer 7

Sulphate ion- react with barium hydroxide (white precipitate)
Carbonate ion- react with acid (CO2 given off)
Chloride, Bromide and iodide ions- react with silver nitrate and chloride gives a white precipitate of silver chloride, bromide gives a cream precipitate of silver bromide and iodide gives a yellow precipitate of silver iodide

Question 8

Flame tests

Answer 8

Lithium- red
Sodium- orange
Potassium- lilac

Question 9

Transition elements, hydroxide precipitates

Answer 9

Copper (II) = Cu^2+ = blue precipitate
Iron (II) = Fe^2+ = grey-green precipitate
Iron (III) = Fe^3+ = orange-brown precipitate

Question 10

Test for alkanes / Alkenes

Answer 10

Add bromide water to the substance and shake
If it is an Alkenes the bromine water will decolourise
Go form orange to colourless
If it is an alkane nothing will happen