5.2.1 Enthalpy changes Flashcards
1
Q
What is enthalpy change?
A
The heat energy released or absorbed per mole in a reaction.
2
Q
+ sign means what in enthalpy change?
A
Heat is absorbed: endothermic. The temperature of the surroundings (thermometer) goes down.
3
Q
- sign means what in enthalpy change?
A
Heat is released: exothermic. The temperature of the surroundings (thermometer) goes up.
4
Q
What unit is enthalpy change?
A
kJ/mole
5
Q
What does enthalpy change rely on?
A
The balance between:
- breaking bonds, which absorbs energy
- making bonds, which releases energy
6
Q
What is an energy level diagram?
A
A way of representing enthalpy change.
