Chemical Testing

Question 1

Describe the chemical test for: Oxygen

Answer 1

Glowing splint
Positive result: relights

Question 2

Describe the chemical test for: Hydrogen

Answer 2

Lit splint
Positive result: squeaky pop

Question 3

Describe the chemical test for: Carbon dioxide

Answer 3

Lime water
Positive result: cloudy/chalky emulsion

Question 4

Describe the chemical test for: Ammonia

Answer 4

Damp red litmus paper
Positive result: turns blue

Question 5

Describe the chemical test for: Chlorine

Answer 5

Damp blue litmus paper
Positive result: turns bleach white

Question 6

Describe the chemical test for: Water

Answer 6

Anhydrous copper sulphate
Positive result: turns blue

Question 7

What part of a compound can be deduced using the flame test?

Answer 7

Positive metal ion

Question 8

What material wire do you use for the flame test?

Answer 8

Platinum or Nichrome

Question 9

Why do we use the materials we do, for the wire in the flame test?

Answer 9

1. Doesn’t produce a colour in the flame test
2. High melting point
3. Unreactive/inert

Question 10

What solution is the wire dipped into, in the flame test?

Answer 10

Hydrochloric acid

Question 11

Why do we dip the wire into a solution, in the flame test?

Answer 11

1. To sterilise/clean the wire so it’s not contaminated
2. To make sure the substance sticks to the wire

Question 12

What colour does Lithium produce in the flame test?

Answer 12

Red

Question 13

What colour does Sodium produce in the flame test?

Answer 13

Yellow

Question 14

What colour does Potassium produce in the flame test?

Answer 14

Lilac

Question 15

What colour does Calcium produce in the flame test?

Answer 15

Orange-red

Question 16

What colour does Copper produce in the flame test?

Answer 16

Blue-green

Question 17

What part of a compound can occasionally be deduced by adding sodium hydroxide?

Answer 17

Positive ion/cation

Question 18

What is the positive result for Copper upon addition of NaOH (sodium hydroxide)?

Answer 18

Blue

Question 19

What is the positive result for Iron (ii) upon addition of NaOH (sodium hydroxide)?

Answer 19

Green

Question 20

What is the positive result for Iron (iii) upon addition of NaOH (sodium hydroxide)?

Answer 20

Brown

Question 21

What is the positive result for Ammonium upon addition of NaOH (sodium hydroxide)?

Answer 21

Fizzing as ammonia gas is produced

Question 22

What is the chemical test for carbonate anions?

Answer 22

Hydrochloric acid
Positive result: fizzing as CO2 is produced

Question 23

What is the chemical test for sulphate anions?

Answer 23

Barium chloride
Positive result: white precipitate

Question 24

How do you test for halide anions?

Answer 24

Add nitric acid and silver nitrate solution (to form acidified silver nitrate)

Question 25

What is the positive result for Chlorine anions?

Answer 25

White precipitate (milk)

Question 26

What is the positive result for Bromide anions?

Answer 26

Cream precipitate (cream)

Question 27

What is the positive result for Iodide anions?

Answer 27

Yellow precipitate (butter)