Chemistry Definitions: Module 3

?
  • Created by: ABusby1
  • Created on: 11-01-16 11:48
Enthalpy, H
The heat energy stored in a chemical system
1 of 18
Exothermic
When the enthalpy is smaller at then end of a reaction than at the beginning. Resulting in heat loss. Deltah -ve.
2 of 18
Endothermic
When the enthalpy is greater at then end of a reaction than at the beginning. Resulting in heat being taken in. Deltah +ve.
3 of 18
Activation energy
Minimum energy required to start a reaction by the breaking of bonds.
4 of 18
Enthalpy profile diagram
Shows the enthalpy of the reactants and products along with the activation energy and enthalpy change.
5 of 18
Standard conditions
Pressure of 100kpa and Temperature of 298K in solution concentration of 1M.
6 of 18
Standard state
The state we find a substance in under standard conditions.
7 of 18
Standard enthalpy change of reaction
Is the enthalpy change that accompanies the moles given in a balanced equation are reacted under standard conditions and in standard states
8 of 18
Standard enthalpy change of combustion
Is the enthalpy change when one mol of reactant is burned completely in oxygen under standard conditions
9 of 18
Standard enthalpy change of formation
Is the enthalpy change when 1 mol of product is formed from its constituent elements in standard states under standard conditions.
10 of 18
Specific heat capacity, C
Energy required to heat 1g of substance by 1K.
11 of 18
Bond enthalpy
Is the enthalpy change when 1 mol of given bonds is broken by homolytic fission in a gaseous state.
12 of 18
Hess' Law
"if a reaction can take place by more than 1 route and the initial and final conditions are the same, the total enthalpy change is the same for each route."
13 of 18
Rate of reaction
The change in concentration of a reactant or product in a given time.
14 of 18
Catalyst
A species than lowers the activation energy of a reaction by providing an alternate route but is not used itself.
15 of 18
Boltzmann distribution
Is the distribution of energies of molecules within a sample at a given temperature.
16 of 18
Dynamic equilibriu m
An equilibrium in a closed system where the rate of forward reaction equals that of the reverse reaction leaving constant concentrations of products and reactants.
17 of 18
Le chatelier's principle
When a change is imposed on a system in dynamic equilibrium the position of the equilibrium will change to minimise the change.
18 of 18

Other cards in this set

Card 2

Front

When the enthalpy is smaller at then end of a reaction than at the beginning. Resulting in heat loss. Deltah -ve.

Back

Exothermic

Card 3

Front

When the enthalpy is greater at then end of a reaction than at the beginning. Resulting in heat being taken in. Deltah +ve.

Back

Preview of the back of card 3

Card 4

Front

Minimum energy required to start a reaction by the breaking of bonds.

Back

Preview of the back of card 4

Card 5

Front

Shows the enthalpy of the reactants and products along with the activation energy and enthalpy change.

Back

Preview of the back of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Enthalpy resources »