Exam practice
Exam questions
Write your answer. Then open the mark scheme and tick each point you made.
- Question 1 of 102 marks
Melting ice is a physical change. Burning wood is a chemical change. State the difference between a physical change and a chemical change.
Mark scheme
- In a chemical change a new substance is made
- In a physical change no new substance is made (accept: the substance stays the same and only its state changes)
- Question 2 of 102 marks
Give two signs that a chemical reaction is taking place.
Mark scheme
- A change of colour
- A gas is given off (accept: bubbles, fizzing)
- A change in temperature (accept: heat or light is given out)
- A solid forms when two solutions are mixed (accept: a precipitate)
- Question 3 of 102 marks
Zinc reacts with hydrochloric acid. Zinc chloride and hydrogen are made. Write the word equation for this reaction.
Mark scheme
- zinc + hydrochloric acid, before the arrow
- zinc chloride + hydrogen, after the arrow
- Question 4 of 102 marks
Explain, using ideas about atoms, why the total mass does not change in a chemical reaction.
Mark scheme
- No atoms are made or destroyed (accept: the same atoms are there before and after)
- The atoms are only rearranged (accept: they are joined in a new way)
- Question 5 of 102 marks
A student burns 4.8 g of magnesium in oxygen. 8.0 g of magnesium oxide is made. Calculate the mass of oxygen that joined with the magnesium.
Mark scheme
- 8.0 − 4.8 (accept: any working that takes the mass of the magnesium away from the mass of the magnesium oxide)
- 3.2 g
- Question 6 of 102 marks
Marble chips are put into acid in an open flask on a balance. The mixture fizzes, and the reading on the balance goes down. Explain why the reading goes down.
Mark scheme
- A gas is made in the reaction (accept: carbon dioxide)
- The gas escapes from the flask into the air, so its mass is no longer on the balance
- Question 7 of 103 marks
Methane is a fuel. It burns in plenty of oxygen. (a) Name the two products. (b) Give the name of this type of reaction.
Mark scheme
- Carbon dioxide
- Water (accept: water vapour, steam)
- Combustion (accept: burning, oxidation)
- Question 8 of 103 marks
Copper carbonate is heated strongly in a test tube. (a) Describe the colour change. (b) Write the word equation for the reaction.
Mark scheme
- It changes from green to black
- copper carbonate, on its own, before the arrow
- copper oxide + carbon dioxide, after the arrow
- Question 9 of 102 marks
A student mixes two solutions in a beaker. The temperature of the mixture falls from 21 °C to 15 °C. State whether the reaction is exothermic or endothermic, and give a reason.
Mark scheme
- Endothermic
- The temperature went down, so energy was taken in from the surroundings
- Question 10 of 102 marks
State two things that are true of every catalyst.
Mark scheme
- It speeds up a reaction
- It is not used up (accept: it is unchanged at the end, it can be used again)