Topic C8 - Chemical Analysis

Question 1

What is the chemical definition for a pure substance?

Answer 1

A substance containing only one element or compound.

Question 2

How do you test the purity of a sample?

Answer 2

By comparing it’s melting or boiling point which that of the pure substance

Question 3

What are formulations?

Answer 3

Useful mixtures with a precise purpose.

Question 4

Give examples of formulations…

Answer 4

Metal alloys
Medicines
Fertilisers
Paints
Fuels
Cosmetics
Food
Cleaning products

Question 5

How do you test for HYDROGEN?

Answer 5

H2 gas in an open test tube
Insert lighted splint
Hydrogen burns quickly with a pop

Question 6

How do you test for OXYGEN?

Answer 6

Oxygen gas in a test tube
Insert glowing splint
Oxygen with relight a glowing splint

Question 7

How do you test for CHLORINE?

Answer 7

Bleaches damp litmus paper white

Question 8

How do you test for CARBON DIOXIDE?

Answer 8

Makes limewater turn cloudy when shaken with or bubbles through it.

Question 9

What is limewater

Answer 9

An aqueous solution of calcium hydroxide.

Question 10

What is the Rf value?

Answer 10

The ratio between the distance travelled by the dissolved substance and the distance travelled by the solvent