Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
171–180 of 442
Question 171
4 marks · Normal
Answer and see the solution →A teacher demonstrates the reaction between 3.0 g of magnesium powder and excess dilute hydrochloric acid in a conical flask. She prepares a second flask with 3.0 g of magnesium ribbon. Both are started at the same time.
(a)[2 marks]Predict which flask will finish producing gas first, and explain your answer.
(b)[2 marks]State the total mass of hydrogen gas produced in each flask. (Give your answer to 2 significant figures.) [M_r(H_2) = 2.0. Ar(Mg) = 24.0] Equation:
Question 172
2 marks · Hard
Answer and see the solution →A student investigates the reaction between magnesium and dilute hydrochloric acid. She uses two samples of magnesium of identical mass: one as a single strip and the other cut into many tiny pieces. State and explain how the rate of reaction will differ between the two samples.
Question 173
5 marks · Hard
Answer and see the solution →A student conducts an experiment to discover how changing the surface area of a solid affects the rate of its reaction with a liquid. She reacts 4.0 g of zinc with 25 cm³ of excess dilute sulfuric acid. She performs the same reaction twice:
(a)[2 marks]Describe a safe method she could use to compare the reaction rate using zinc granules and zinc powder, and state a measurement that would provide evidence for which reaction is faster.
(b)[2 marks]Explain, in terms of particle collisions, why the reaction rate changes when using zinc powder instead of granules.
(c)[1 mark]Suggest one other variable, apart from surface area, that must be kept the same to ensure a fair comparison.
Question 174
2 marks · Hard
Answer and see the solution →Explain, using collision theory, why a powdered solid reacts more quickly with a liquid than the same mass of solid in one lump.
Question 175
1 mark · Easy
Answer and see the solution →State what happens to the rate of a reaction if the concentration of a reactant is increased, assuming all other conditions remain the same.
Question 176
3 marks · Easy
Answer and see the solution →A student dilutes 10.0 cm³ of 2.00 mol/dm³ sodium thiosulfate solution by adding water to make a total volume of 50.0 cm³.
(a)[1 mark]State the formula used to calculate the concentration of the diluted solution.
(b)[2 marks]Calculate the concentration of sodium thiosulfate after dilution.
Question 177
2 marks · Easy
Answer and see the solution →In an experiment, 0.27 g of oxygen gas is produced in 45 seconds during the reaction of hydrogen peroxide with manganese(IV) oxide. Calculate the average rate of oxygen production during this time. Give your answer in g/s.
Question 178
2 marks · Easy
Answer and see the solution →A graph plots the rate of a chemical reaction against the concentration of a reactant. The graph is a straight line that passes through the origin. Explain what this tells you about the relationship between the rate of the reaction and the concentration of the reactant.
Question 179
3 marks · Easy
Answer and see the solution →The table gives the results from an experiment measuring the rate of a reaction at two different concentrations of sulfuric acid.
(a)[0 marks]Concentration of acid (mol/dm³) Rate of reaction (g/s) 0.60 0.008 1.20 0.016 (b)[1 mark]Describe the effect of doubling the concentration on the rate of reaction.
(c)[2 marks]Explain why doubling the concentration causes this effect, in terms of particle collisions.
Question 180
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.