GCSE Combined Science Chemistry 2

Question 1

What is the test for carbon dioxide gas?

Accepted Answer

It turns limewater milky (cloudy)

Answer

It relights a glowing splint

Answer

It makes a squeaky pop with a burning splint

Answer

It bleaches damp litmus paper

Question 2

In electrolysis of a molten ionic compound, which electrode do positive ions migrate to?

Accepted Answer

The cathode (negative electrode)

Answer

The anode (positive electrode)

Answer

Both electrodes equally

Answer

Neither electrode

Question 3

What is the purpose of a catalyst in a chemical reaction?

Accepted Answer

To speed up the reaction by lowering the activation energy

Answer

To increase the amount of product formed

Answer

To make the reaction release more energy

Answer

To change the products of the reaction

Question 4

What is the formula for calculating the number of moles of a substance?

Accepted Answer

Moles = mass ÷ Mr

Answer

Moles = mass × Mr

Answer

Moles = Mr ÷ mass

Answer

Moles = mass + Mr

Question 5

Which process is used to separate crude oil into its fractions?

Accepted Answer

Fractional distillation

Answer

Filtration

Answer

Crystallisation

Answer

Chromatography

Question 6

An atom has 11 protons, 12 neutrons, and 11 electrons. What is its mass number?

Accepted Answer

23

Answer

11

Answer

12

Answer

34