Chapter 9 enthalpy

Cards (9)

What is enthalpy?
Heat content that is stored in a chemical system
State the conservation of energy
If heat is released from a chemical system, the amount that enters the surroundings is exactly the same as the amount that leaves the system.
Define an exothermic bond
More energy is given out making bonds than is taken in when breaking bonds.
Define an endothermic reaction
Less energy is given out making bonds than is taken in when breaking bonds.
What is activation energy?
Activation energy is the minimum amount of energy required for a chemical reaction to occur by the breaking of bonds.
What is average bond enthalpy?
The enthalpy change that takes place when breaking by homolytic fission 1 mole of bonds in a molecule in a gaseous state.
What is the standard enthalpy change of reaction?
The enthalpy change that occurs when molar quantities stated in an equation react under standard conditions with all reactants and products in their standard state.
What is standard enthalpy change of combustion?
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions and all reactants and products are in there standard states
What is standard enthalpy change of formation?
The enthalpy change that takes place when one mole of a substance is formed from its constituent atoms under standard conditions and all reactants and products are in there standard state.