Energy ChangesCommon Misconceptions

Common Misconceptions

Part of Reaction ProfilesGCSE Chemistry

This common misconceptions covers Common Misconceptions within Reaction Profiles for GCSE Chemistry. Revise Reaction Profiles in Energy Changes for GCSE Chemistry with 28 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 9 of 13 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 9 of 13

Practice

28 questions

Recall

15 flashcards

⚠️ Common Misconceptions

Misconception 1: "Catalysts provide energy for the reaction"

Catalysts do NOT provide energy. They work by offering an alternative reaction pathway that has a LOWER activation energy. This means more of the colliding particles already have enough energy to react, so the rate increases. The catalyst itself does not supply any energy to the reaction, and the overall ΔH remains unchanged.

Misconception 2: "The activation energy is the total energy released by the reaction"

Activation energy and ΔH are completely different measurements. Activation energy is the energy needed to START the reaction (reactants to peak). ΔH is the OVERALL energy change (reactants to products). For an exothermic reaction, the peak is higher than the reactants but the products are lower — so Ea and ΔH point in different directions.

Misconception 3: "The reaction profile curve must always be a smooth hump"

The reaction profile is always shown with a smooth curve that goes up to a peak and back down. However, the key point is that the curve must go UP to a peak before it comes down (even for exothermic reactions), because activation energy is always required. If you draw the reactants straight down to products with no peak, that is scientifically incorrect.

Keep building this topic

Read this section alongside the surrounding pages in Reaction Profiles. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Reaction Profiles

What does activation energy represent on a reaction profile?

  • A. The minimum energy particles need to react
  • B. The total energy released during the reaction
  • C. The energy stored in the reactants
  • D. The difference in energy between products and reactants
1 markfoundation

Explain how a catalyst affects the activation energy shown on a reaction profile. [2 marks]

2 marksstandard

Quick Recall Flashcards

What is activation energy?
The minimum energy particles need to react when they collide
What does the y-axis show on a reaction profile?
Energy

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