Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
231–240 of 442
Question 231
2 marks · Hard
Answer and see the solution →Explain why the same catalyst cannot usually be used for every type of chemical reaction.
Question 232
1 mark · Easy
Answer and see the solution →State what a catalyst does to the activation energy, as shown on a reaction profile diagram.
Question 233
3 marks · Easy
Answer and see the solution →(a)[1 mark]Describe the energy change from reactants to products in an exothermic reaction profile diagram.
(b)[1 mark]On a reaction profile diagram, where is the activation energy shown?
(c)[1 mark]Explain how adding a catalyst would change the appearance of the reaction profile diagram.
Question 234
2 marks · Easy
Answer and see the solution →A certain reaction without a catalyst has an activation energy of 150 kJ/mol. When a catalyst is used, the alternative pathway requires only 80 kJ/mol. Calculate the reduction in activation energy provided by the catalyst.
Question 235
2 marks · Easy
Answer and see the solution →Explain why not all particles react, even with a catalyst, and how this is shown in a reaction profile diagram.
Question 236
3 marks · Easy
Answer and see the solution →(a)[1 mark]Values for a reaction profile. Description Energy (kJ/mol) Reactants 120 Peak without catalyst 200 Peak with catalyst 140 Products 60 Calculate the activation energy without a catalyst.
(b)[1 mark]What is the activation energy with a catalyst?
(c)[1 mark]Describe how the catalyst affects the reaction profile diagram, using the values from the table.
Question 237
1 mark · Easy
Answer and see the solution →On a reaction profile diagram, what does the vertical distance between the reactants and the peak of the curve represent?
Question 238
3 marks · Easy
Answer and see the solution →(a)[2 marks]Draw and label a reaction profile diagram for an exothermic reaction, showing the energy of reactants, products, and the activation energy.
(b)[1 mark]Explain how a catalyst would change the shape of this diagram.
Question 239
2 marks · Easy
Answer and see the solution →The energy of the reactants is 180 kJ/mol and the energy at the peak of the reaction profile (with a catalyst) is 130 kJ/mol. Calculate the activation energy for this pathway.
Question 240
2 marks · Normal
Answer and see the solution →Explain, with reference to activation energy, how a catalyst affects a reaction profile diagram.