Chemistry 5070 · O Level · Exothermic and endothermic reactions
Exothermic and endothermic reactions — practice question
Photosynthesis is a chemical reaction that takes place in the leaves of green plants.
Carbon dioxide and water are changed into glucose and oxygen.
$6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$
This reaction absorbs energy and is catalysed by enzymes.
(a)[3]
Using the axes provided, sketch an energy profile diagram for photosynthesis. Make sure to label the axes, the enthalpy change, and both the reactants and products.
(b(i))[1]
What do we mean by an enzyme?
(b(ii))[1]
State the effect enzymes have on reactions.
(c)[2]
Explain why the rate of photosynthesis rises as the temperature increases.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Vertical axis labelled energy/enthalpy and horizontal axis labelled progress of reaction” …