Energy changes Flashcards
What is key about exothermic reactions?
They TRANSFER ENERGY from the reacting molecules TO THE SURROUNDINGS.
In exothermic reactions why do the products have less energy than the reactants?
As the energy has been transferred to the SURROUNDINGS.
Name two uses of exothermic reactions.
- Hand warmers
- Self-heating cans e.g. for food or drink
What is key about endothermic reactions?
They TAKE IN ENERGY from their surroundings.
Give one example of an endothermic reaction.
Thermal decomposition.
In endothermic reactions why do the products have more energy than the reactants?
As the energy has been TAKEN IN from the surroundings
What is the activation energy?
The MINIMUM OF ENERGY that particles must have in order to REACT.
Why are endothermic reactions shown as positive?
As energy has been GAINED.
Why are exothermic reactions shown as negative?
As energy has been TRANSFERRED FROM the chemicals.
What type of reaction is the making of bonds?
Exothermic (releases energy).
What type of reaction is the breaking of a chemical bond?
Endothermic.
