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Carbon dioxide reacts with hydrogen gas to form carbon monoxide and water vapour in a sealed flask, according to the following equation - HSC - SSCE Chemistry - Question 18 - 2023 - Paper 1
Question 18
Carbon dioxide reacts with hydrogen gas to form carbon monoxide and water vapour in a sealed flask, according to the following equation. CO2(g) + H2(g) ⇌ CO(g) + H2... show full transcript
Worked Solution & Example Answer:Carbon dioxide reacts with hydrogen gas to form carbon monoxide and water vapour in a sealed flask, according to the following equation - HSC - SSCE Chemistry - Question 18 - 2023 - Paper 1
Step 1
Temperature change at time t
Answer
At time t, the schematic graph shows a decrease in the rate of the forward reaction, indicating that the equilibrium is responding to the imposed temperature change. According to Le Chatelier's Principle, reducing the temperature shifts the equilibrium towards the exothermic direction which produces heat. Thus, the temperature change at time t is a decrease.
Step 2
ΔH of the forward reaction
Answer
The forward reaction (the formation of CO and H2O from CO2 and H2) is generally considered to be endothermic if increasing temperature favors products. Since the question implies an increase in temperature favors the products, the ΔH for the forward reaction is negative (−). This suggests that heat is released when the products form.