Tests for Gases and water (pg 53)

Question 1

What is the test for chlorine?

Answer 1

• Chlorine bleaches damp red litmus paper, turning it white
  -may turn red for a moment (solution of chlorine is acidic)

Question 2

What is the test for Oxygen?

Answer 2

-oxygen relights a glowing splint

Question 3

What is the test for Carbon Dioxide?

Answer 3

• turns limewater cloudy
• bubble the gas through a test tube of limewater and watch what happens

Question 4

What is the test for Hydrogen?

Answer 4

• Hydrogen makes a “squeaky pop” with a lighted splint.
• (The noise comes from the hydrogen burning with the oxygen in the air to form water)

Question 5

What is test for Ammonia?

Answer 5

• Ammonia turns damp red litmus paper blue
• (it has a very strong smell)

Question 6

What can be used as a test for water?

Answer 6

Copper (II) sulfate

Question 7

How do you form blue crystals?

Answer 7

• when copper sulfate is bound to water (water of crystallisation)

Question 8

How can you get rid of the water when making crystals?

Answer 8

• heat the blue hydrated copper (II) sulfate crystals

Question 9

What do the blue hydrated copper (II) sulfate crystals leave?

Answer 9

• leaves a white anhydrous copper (II) sulfate powder, which doesnt have any water bound to it

Question 10

What do you then add to the white powder?

Answer 10

• water to get the blue crystals back again

Question 11

How do you test for water?

Answer 11

• add anhydrous copper (II) sulfate and see if the white powder turns blue

Question 12

What does it mean if a sample is pure?

Answer 12

• its only made up of one substance

Question 13

What will pure water boil and freeze at?

Answer 13

boil- 100 degrees
freeze- 0 degrees