Reactions/Experiments/Colours

Question 1

Reaction of lithium in water

Answer 1

Fizzes and floats on water’s surface

Question 2

Reaction of sodium in water

Answer 2

Fizzes, floats of waters surface and melts

Question 3

Reaction of potassium in water

Answer 3

Lilac flame

Question 4

Group 7 elements at room temperature and pressure

Answer 4

• Chlorine: green gas
• Bromine: brown liquid
• Iodine: grey solid

Question 5

Predicting group 7 elements

Answer 5

• Fluorine: yellow gas

- Astatine: black solid

Question 6

Reaction of magnesium with oxygen

Answer 6

Bright white flame 
Produces MgO (white precipitate) - basic

Question 7

Reaction of carbon with oxygen

Answer 7

Yellow flame
Produces CO2 (colourless gas) - acidic

Question 8

Reaction of sulfur with oxygen

Answer 8

Blue flame
Produces SO2 (colourless gas) - acidic

Question 9

Combustion of Hydrogen

Answer 9

Burns in oxygen explosively
Colourless flame
Water

Question 10

Flame test - Li

Answer 10

Crimson red

Question 11

Flame test - Na

Answer 11

Orange

Question 12

Flame test - K

Answer 12

Lilac flame

Question 13

Testing for ammonium ions

Answer 13

• Add sodium hydroxide
• Hold over damp red litmus paper
• If ammonium ions are present, the litmus paper will turn blue

Question 14

Testing for copper ions

Answer 14

Add sodium hydroxide

Blue precipitate forms

Question 15

Testing for Fe(II) ions

Answer 15

Add sodium hydroxide

Green precipitate forms

Question 16

Testing for Fe(III) ions

Answer 16

Add sodium hydroxide

Brown precipitate forms

Question 17

Testing for chloride ions

Answer 17

1. add dilute nitric acid
2. add silver nitrate solution
3. white precipitate forms

Question 18

Testing for bromide ions

Answer 18

1. add dilute nitric acid
2. add silver nitrate solution
3. cream precipitate forms

Question 19

Testing for iodide ions

Answer 19

1. add dilute nitric acid
2. add silver nitrate solution
3. yellow precipitate forms

Question 20

Testing for sulfate ions

Answer 20

1. add hydrochloric acid
2. add barium chloride
3. white precipitate forms

Question 21

Testing for carbonate ions

Answer 21

1. add hydrochloric acid
2. you will observe fizzing (CO2) forms
3. Add limewater - should turn milky

Question 22

Testing for hydrogen gas

Answer 22

Use a lit split – pop

Question 23

Testing for oxygen gas

Answer 23

use a glowing splint – will relight

Question 24

Testing for CO2 gas

Answer 24

bubble the gas through limewater – turns milky

Question 25

Testing for ammonia gas

Answer 25

Use damp red litmus paper -- turns blue

Question 26

Testing for chlorine gas

Answer 26

use moist litmus paper -- turns it white (bleaches)