C3 = Tests

Question 1

What is a flame test

Answer 1

Use a clean, sterilised loop to dip into the solution of given test. Note what colour it goes and clean with acid and water.

Question 2

How to tell the difference between Lithium and Calcium

Answer 2

Test the solutions with sodium hydroxide.

If a white precipitate forms = calcium
Nothing forms = Lithium

Question 3

What are the metal ions that could be present when excess sodium hydroxide is added?

Answer 3

If a precipitate forms = Calcium or Magnesium

Aluminium dissolves if too much is put in

Question 4

What colours are copper, iron 2 and iron 3

Answer 4

Copper = Blue

Iron2 = Green

Iron3 = Brown

Question 5

Say sodium hydroxide is added and a green solution forms but in 2 mins it’s brown. Is it iron 2 or iron 3?

Answer 5

Iron 2

Take first result because it’s probably oxidised and changed colour

Question 6

How to test for a sulfate ion

Answer 6

Add hydrochloric acid and barium chloride.

If a white precipitate forms = sulfate ions are present

Question 7

How to test for halide ions

Answer 7

Add nitric acid and sliver nitrate.

If a white precipitate forms = halide ion

Chloride = white 
Bromide = cream
Iodide = yellow

Question 8

How to test for carbonate ions

Answer 8

Add dilute hydrochloric acid.

Fizzes AND turns limewater milky = carbonate ion

Question 9

Give the completed equation for iron3 + sodium hydroxide

Answer 9

Fe3 + 3OH = Fe(OH)3

Question 10

What are the colours for the positive ions (flame test) :

Lithium 
Sodium
Potassium
Calcium
Barium

Answer 10

Lith = Red
Sodium = Yellow
Pot = Lilac
Cal = Red
Bar = Green

Question 11

How to test for nitrate ions

Answer 11

Add sodium hydroxide and powdered aluminium.

Use red litmus paper to see if ammonia gas is released, if so it turns blue and nitrate ions are present.