Name the two main gases that make up the Earth's atmosphere today.

Explain why today's atmosphere is different from the Earth's early atmosphere.

How were the oceans formed?

List three ways in which human activity is changing the atmosphere.

Apart from humans, what else is changing the atmosphere?

Describe how you could investigate the proportion of oxygen in the air.

Name the three types of rock.

What type of rock is marble and how is it formed?

What type of rock is chalk?

Describe the difference in the way the crystals of extrusive and intrusive rocks form.

Name three building materials made from limestone.

Give two positive and two negative points about limestone quarrying.

What is thermal decomposition?

Write down the symbol equation showing the thermal decomposition of limestone.

How could you test for carbon dioxide in a thermal decomposition reaction?

Write down the symbol equation for the thermal decomposition reaction of zinc carbonate.

What product can be made by adding water to calcium oxide and why is it useful?

Are atoms lost and made in a reaction or just rearranged?

If you carry out a reaction in a sealed container, what would you notice about the mass of f the reactants and products?

What is a precipitate?

What does the number in front of a formula apply to?

What is the state symbol for 'dissolved in water'?

Do acids have a pH greater or less than 7?

Name the acid produced by the stomach.

How do indigestion tablets work?

What do you get when you react an acid with a metal oxide.

Write a balanced symbol equation for the reaction of hydrochloric acid with sodium carbonate.

Is the anode positive or negative?

Are anions or cations attracted to the anode?

How would you test for hydrogen gas?

Name a product of the electrolysis of salt.