Chemistry - chemical tests

Question 1

For the flame test of potassium compounds, what colour flame appears?

Answer 1

Lilac flame

Question 2

For the flame test of copper(II) compounds, what colour flame appears?

Answer 2

Blue-green flame

Question 3

For the flame test of sodium compounds, what colour flame appears?

Answer 3

Yellow flame

Question 4

For the flame test of lithium compounds, what colour flame appears?

Answer 4

Red flame

Question 5

For the flame test of calcium compounds, what colour flame appears?

Answer 5

Orange-red flame

Question 6

What is formed when copper(II) solutions are reacted with sodium hydroxide?

Answer 6

Blue precipitate

Question 7

What is formed when iron(II) solutions are reacted with sodium hydroxide?

Answer 7

Green precipitate

Question 8

What is formed when iron(III) solutions are reacted with sodium hydroxide?

Answer 8

Brown precipitate

Question 9

Describe how to test for copper(II), iron(II) or iron(III)

Answer 9

Make a solution
Add sodium hydroxide solution
Note the precipitate colour

Question 10

For the test for halides, what is formed when testing for the presence of chloride ions?

Answer 10

A white precipitate

Question 11

For the test for halides, what is formed when testing for the presence of bromide ions?

Answer 11

A cream precipitate

Question 12

For the test for halides, what is formed when testing for the presence of iodide ions?

Answer 12

A yellow precipitate

Question 13

Describe the test for hydrogen

Answer 13

Place a flaming splint near the gas

Squeaky pop

Question 14

Describe the test for oxygen

Answer 14

Place a glowing splint in a test tube of the gas

Relights

Question 15

Describe the test for carbon dioxide

Answer 15

Bubble the gas through limewater

Goes cloudy

Question 16

Describe the test for ammonia

Answer 16

Place damp red litmus paper in the gas

Goes blue

Question 17

Describe the test for chlorine

Answer 17

Place damp blue litmus paper in the gas
Goes red
Then bleaches

Question 18

How do you carry out a flame test?

Answer 18

Dip a nichrome wire into concentrated hydrochloric acid
Add the solid to the wire
Place in a Bunsen flame
Record and compare the colour of the flame

Question 19

Describe the test for ammonium

Answer 19

Add dilute nitric acids to make an acidic solution
Add sodium hydroxide solution
Heat
Place red litmus paper in the gas
Goes blue

Question 20

Describe how to test for the presence of water

Answer 20

Add anhydrous copper(II) sulphate

Goes from white to blue

Question 21

Describe how to test if water is pure

Answer 21

It will melt at 0C
(Melting point of 0C)
It will boil at 100C
(Boiling point of 100C)

Question 22

Describe how to test for a halide

Answer 22

Make a solution
Add nitric acid
Add silver nitrate solution
Note the precipitate colour

Question 23

Describe the test for sulfate

Answer 23

Make a solution
Add hydrochloric acid
Add barium chloride solution
White precipitate forms

Question 24

Describe the test for carbonate

Answer 24

Make a solution
Add hydrochloric acid
Effervescence occurs
Test for carbon dioxide:
(Bubble through limewater
Goes cloudy)

Question 25

What colour is methyl orange in acid?

Answer 25

Red

Question 26

What colour is methyl orange in alkali?

Answer 26

Yellow

Question 27

What colour is litmus in acid?

Answer 27

Red

Question 28

What colour is litmus in alkali?

Answer 28

Blue

Question 29

What colour is phenolphthalein in acid?

Answer 29

Colourless

Question 30

What colour is phenolphthalein in alkali?

Answer 30

Pink

Question 31

What ions are responsible for an acidic solution?

Answer 31

H+

Question 32

What ions are responsible for an alkali solution?

Answer 32

OH-