Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
191–200 of 442
Question 191
2 marks · Hard
Answer and see the solution →A student investigates the reaction between calcium carbonate and hydrochloric acid. State, with a reason, what happens to the rate of reaction if the concentration of hydrochloric acid is reduced to a third, assuming all other conditions remain the same.
Question 192
5 marks · Hard
Answer and see the solution →A student prepares dilute hydrochloric acid for a reaction by adding water to a known volume of 2.50 mol/dm³ hydrochloric acid. She then uses the solution to react with marble chips.
(a)[2 marks]She mixes 10.0 cm³ of 2.50 mol/dm³ acid with 30.0 cm³ of water to make 40.0 cm³ of solution. Calculate the concentration, in mol/dm³, of the hydrochloric acid after dilution.
(b)[2 marks]She repeats the process, using 25.0 cm³ of 2.50 mol/dm³ acid topped up with water to 40.0 cm³. Calculate the new concentration, in mol/dm³, after dilution.
(c)[1 mark]State the formula used to calculate the final concentration when diluting a solution.
Question 193
2 marks · Hard
Answer and see the solution →An experiment produced 0.46 g of carbon dioxide in the first 20 seconds during the reaction of marble chips with dilute hydrochloric acid. Calculate the average rate of carbon dioxide production, giving your answer in g/s. Show your working.
Question 194
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 195
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 196
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 197
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 198
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 199
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 200
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.