This question is about reversible reactions and chemical equilibrium - AQA - GCSE Chemistry - Question 6 - 2015 - Paper 3
Question 6
This question is about reversible reactions and chemical equilibrium.
6 (a) (i) What is meant by a closed system?
A closed system is defined as a scenario where no... show full transcript
Worked Solution & Example Answer:This question is about reversible reactions and chemical equilibrium - AQA - GCSE Chemistry - Question 6 - 2015 - Paper 3
Step 1
What is meant by a closed system?
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A closed system is defined as a scenario where nothing can enter or leave the system, ensuring that the reaction occurs in a sealed environment.
Step 2
Explain why, when a reversible reaction reaches equilibrium, the reaction appears to have stopped.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
When a reversible reaction reaches equilibrium, the rate of the forward reaction is equal to the rate of the backward reaction. Consequently, there are no net changes in the concentrations of reactants and products, which gives the appearance that the reaction has ceased.
Step 3
Name a natural resource from which hydrogen is produced.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Natural gas is a key resource from which hydrogen is produced, along with other sources like water and hydrocarbons.
Step 4
Explain how a catalyst speeds up a reaction.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A catalyst speeds up a reaction by providing an alternative pathway with a lower activation energy. This allows more reactant particles to collide effectively, increasing the rate of reaction.
Step 5
What happens to the amount of ammonia produced at equilibrium if the pressure is increased? Give a reason for your answer.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The amount of ammonia produced will increase under higher pressure because the equilibrium will shift towards the side of the reaction with fewer gas molecules, thereby favoring the forward reaction.
Step 6
Draw an arrow to show the activation energy on the diagram in Figure 3.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The activation energy can be illustrated by a vertical arrow from the reactants to the peak of the energy level diagram, indicating the energy required to initiate the reaction.
Step 7
How does the diagram in Figure 3 show that the reaction is endothermic?
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The reaction is indicated as endothermic because the energy level of products is higher than that of the reactants, signifying that energy is absorbed during the reaction.
Step 8
Suggest what effect, if any, increasing the temperature will have on the amount of hydrogen iodide at equilibrium. Give a reason for your answer.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Increasing the temperature will result in a decrease in the amount of hydrogen iodide present because the equilibrium will shift in the direction of the endothermic reaction, favoring the products.
