The reaction
A + B → C; ΔH negative
involves a two-step process
A + B → X; ΔH positive
X → C; ΔH negative
Which one of the following diagrams best represents the energy changes during the course of the reaction? - VCE - SSCE Chemistry - Question 19 - 2007 - Paper 1
Question 19
The reaction
A + B → C; ΔH negative
involves a two-step process
A + B → X; ΔH positive
X → C; ΔH negative
Which one of the following diagrams best represents the... show full transcript
Worked Solution & Example Answer:The reaction
A + B → C; ΔH negative
involves a two-step process
A + B → X; ΔH positive
X → C; ΔH negative
Which one of the following diagrams best represents the energy changes during the course of the reaction? - VCE - SSCE Chemistry - Question 19 - 2007 - Paper 1
Step 1
A + B → X; ΔH positive
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Answer
In the first step, A and B combine to form X, which is an endothermic reaction. This means that energy is absorbed from the surroundings, resulting in an increase in the potential energy of the system as it transitions from A + B to X.
Step 2
X → C; ΔH negative
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Answer
In the second step, the formation of C from X is an exothermic reaction. This releases energy into the surroundings, leading to a decrease in the potential energy of the system as it transitions to the product C.
Step 3
Final Diagram Selection
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Answer
Given the characteristics of the energy changes in the reactions, the correct diagram would show an overall increase in energy from A + B to X, followed by a decrease as the reaction proceeds from X to C, indicating a net release of energy. Based on these characteristics, option D best represents these energy changes during the course of the reaction.
