Chemical analysis

Question 1

What is one of the simplest ways to measure weather a substance is pure?

Answer 1

To measure its MELTING and BOILING POINT.

Question 2

What does a pure substance melt at?

Answer 2

A SPECIFIC FIXED TEMPERATURE.

Question 3

What does a pure substance boil at?

Answer 3

A SPECIFIC FIXED BOILING POINT.

Question 4

Describe how to test for the gas hydrogen.

Answer 4

• Remove the bung and insert a BURNING SPLINT.
• Hydrogen gas burns rapidly and produces a POP SOUND.

Question 5

Describe how to test for the gas oxygen.

Answer 5

• To test for oxygen, we use a GLOWING SPLINT.
• If we place this into a test tube of oxygen the splint RELIGHTS.

Question 6

Describe how to test for the gas carbon dioxide.

Answer 6

• To test for carbon dioxide, we use LIMEWATER.
• Draw some of the gas into a PLASTIC PIPETTE.
• BUBBLE the gas through the limewater.
• If we repeat this, the limewater may turn CLOUDY (telling us that was CO2).

Question 7

What is limewater?

Answer 7

Limewater is an aqueous solution of CALCIUM HYDROXIDE.

Question 8

Describe how to test for the gas chlorine.

Answer 8

• Insert DAMP LITMUS PAPER into the mouth of the test tube.
• Chlorine BLEACHES the litmus paper and turns it WHITE.