GCSE CHEMISTRY ENERGY CHANGES EXAM REVISION QUESTIONS WITH VERIFIED SOLUTIONS LATEST 2025 UPDATE.

GCSE CHEMISTRY ENERGY CHANGES EXAM REVISION QUESTIONS
WITH VERIFIED SOLUTIONS LATEST 2025 UPDATE.




The 2 or more substances that react together in a reaction - ANSWER- Reactants



The substance/s made in a reaction - ANSWER- Products


A reaction where heat energy is made and given off to the surroundings so the temperature rises -
ANSWER- Exothermic reaction


A reaction where heat energy is taken in from the surroundings so the temperature decreases -
ANSWER- Endothermic reaction



Energy needed to start a reaction - ANSWER- Activation energy


A graph which tells us the energy of reactants and products as reaction occurs with energy on the
Y axis and time on the X axis - ANSWER- Reaction Profile


The amount of energy that will either break a bond between atoms or create a bond - ANSWER-
Bond energy


Here the activation energy is less than that used to form bond and so energy is lost to the
surrounding and the energy change is negative - ANSWER- Draw a reaction profile for an
exothermic reaction


Here the activation energy is larger than that used to form bonds and so energy is gained from the
surrounding and there is a positive energy change - ANSWER- Draw a reaction profile for an
endothermic reaction