Energy changes

Question 1

What is the law of conservation of energy?

Answer 1

Energy is conserved in a reaction. The energy before a chemical reaction is the same as the energy afterwards.

Question 2

What is an exothermic reaction and an example?

Answer 2

A reaction that transfers energy to the surroundings, combustion

Question 3

What is an endothermic reaction and an example?

Answer 3

One that takes in energy from the surroundings, thermal decomposition

Question 4

How do you draw a reaction profile for a exothermic reaction?

Answer 4

Reactants are high up
Products are lower
Activation energy is little higher than reactants

Question 5

How do you draw a reaction profile for a endothermic reaction?

Answer 5

Reactants low
Products high
Activation energy is large, bigger than product

Question 6

What two things happen in a chemical reaction?

Answer 6

Energy must be supplied to break bonds in the reactants
Energy is released when bonds in the products are formed

Question 7

What type of reaction has a negative energy change and why?

Answer 7

An exothermic reaction because the chemicals have lost energy to their surroundings

Question 8

What type of reaction has a positive energy change?

Answer 8

An endothermic reaction as the chemicals have gained energy from the environment