Chapter 7 - Chemistry Flashcards
What is the rule on energy?
Energy is conserved in chemical reactions. It is neither created nor destroyed
What is an exothermic reaction?
A reaction in which energy is transferred from the reacting substances to their surroundings.
What is an example of an exothermic reaction?
The combustion of methane gas
What is an endothermic reaction?
A reaction in which energy is transferred to the reacting substances from their substances
What is an example of an endothermic reaction?
The decomposition of calcium carbonate.
When can exothermic changes happen?
They can be used in hand warmers and self-heating cans
When can endothermic changes be used?
In instant cold packs for sports injuries
What does a curved line show in a reaction profile?
It shows the course of the reaction
What does the difference in energy between the reactants and the peak of the curve indicate?
The energy input required for the reaction to take place
What does it mean when the products are at a lower energy level than the reactants?
This means that when the reactants form the products, energy is transferred to the surroundings. Therefore this is an exothermic reaction profile
What happens as the reactants react to form products?
Energy is transferred from the surroundings to the reaction mixture, therefore this is an endothermic reaction profile.
What do breaking bonds do?
Absorb energy
What do forming bonds do?
Release energy?
