C6 - Energy changes in chemical reactions

Question 1

What is an exothermic reaction? [2]

Answer 1

A reaction that transfers thermal energy to the surroundings leading to an increase in temperature

Question 2

What is an endothermic reaction? [2]

Answer 2

A reaction that absorbs thermal energy from the surroundings leading to a decrease in temperature

Question 3

What is enthalpy change? [1]

Answer 3

The difference between the energy required to break bonds and the energy given out when bonds are made

Question 4

Explain an exothermic reaction in terms of bond breaking and bond making [2]

Answer 4

Less energy is absorbed to break bonds and more energy is released when bonds are made

Question 5

Explain an endothermic reacion in terms of bond breaking and bond making [2]

Answer 5

More energy is absorbed to break bonds and less energy is released when bonds are made

Question 6

What is activation energy? [1]

Answer 6

The minimum energy colliding particles need to have in order to react