Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
81–90 of 183 · Easy
Question 81
1 mark · Easy
Answer and see the solution →A student mixes 16.0 cm³ of 1.50 mol/dm³ hydrochloric acid with water to make 40.0 cm³ of solution. State the concentration of hydrochloric acid after dilution, leaving your answer as a formula or calculation.
Question 82
3 marks · Easy
Answer and see the solution →In an experiment, 0.40 g of carbon dioxide is produced in the first 50 seconds during a reaction between calcium carbonate and hydrochloric acid.
(a)[1 mark]Write down the formula for calculating the average rate of reaction.
(b)[2 marks]Calculate the average rate of reaction in g/s.
Question 83
2 marks · Easy
Answer and see the solution →A student plots a graph showing the initial rate of reaction versus concentration of a reactant. At 0.80 mol/dm³, the rate is 0.011 g/s. Predict the rate if the concentration is increased to 1.60 mol/dm³, assuming the rate is directly proportional to concentration.
Question 84
1 mark · Easy
Answer and see the solution →State what happens to the rate of a reaction between two gases when the pressure is increased.
Question 85
3 marks · Easy
Answer and see the solution →A student wants to increase the rate of a reaction involving only liquids. She decides to increase the pressure.
(a)[2 marks]Explain why this change in pressure will have little effect on the rate of reaction.
(b)[1 mark]Describe how the particles in a liquid are arranged.
Question 86
2 marks · Easy
Answer and see the solution →A reaction between two gases at a certain pressure takes 16 minutes. When the pressure is doubled, the rate of reaction doubles. Calculate the new time taken for the reaction to complete at the higher pressure.
Question 87
2 marks · Easy
Answer and see the solution →Explain why increasing the pressure does not significantly affect the rate of reaction for a reaction involving only solids.
Question 88
3 marks · Easy
Answer and see the solution →The table shows the completion time for a reaction between two gases at different pressures.
Reaction time at different pressures Pressure / kPa Completion time / min 80 20 160 10 240 6.7 (a)[1 mark]Describe the relationship between pressure and completion time for this reaction.
(b)[2 marks]Explain, using particle theory, why increasing the pressure causes this effect.
Question 89
1 mark · Easy
Answer and see the solution →State why changing the pressure has little effect on the rate of a reaction involving only liquids.
Question 90
3 marks · Easy
Answer and see the solution →Consider a reaction between two gases in a sealed container.
(a)[1 mark]Describe what happens to the rate of reaction if the pressure of the gases is increased.
(b)[2 marks]State why this happens, linking your answer to particle collisions.