Bond Enthalpy

Question 1

What is an exothermic reaction?

Answer 1

A reaction where the chemicals in the reaction loose energy to the surroundings, increasing the temperature of the surroundings

Question 2

What is an endothermic reaction?

Answer 2

A reaction where the chemicals in the reaction gain energy from the surroundings, decreasing the temperature of the surroundings

Question 3

What is Average Bond Enthalpy?

Answer 3

The amount of energy in a mole of a bond averaged out across all the molecules that contain that bond

Question 4

Equation to work out the change in energy in a reaction of chemicals whose mass/volume is known?

Answer 4

q=mcΔT
q = Energy (J)
m = mass (g)
c = Specific heat capacity (Jg⁻¹K⁻¹)
ΔT = Change in Temperature (K)

Question 5

How to use energy released or taken in from a chemical reaction of known mass/volume to work out bond enthalpy?

Answer 5

ΔH = q/n
n = number of moles (mol)
q = Energy (J)
ΔH = change in energy in a mole of the bonds (Jmol⁻¹)
n = mass/Mr
n = volume(cm³)/1000 * concentration (moldm⁻³)