Thermodynamics And Energetics

Question 1

What are standard conditions?

Answer 1

100 KPa and stated temperature (298k)

Question 2

Define mean bond enthalpy

Answer 2

Average enthalpy change when 1 mole of a bond is broken in gas state

Question 3

Define standard enthalpy of formation

Answer 3

Enthalpy change when 1 mole is formed under standard conditions

Question 4

Define standard enthalpy of combustion

Answer 4

Enthalpy change when 1 mole is completely burnt in O2

Question 5

Define standard enthalpy of atomisation

Answer 5

Enthalpy change when 1 mole of gaseous atoms forms from its standard state

Question 6

Define the first ionisation energy

Answer 6

Enthalpy change when 1 mole of atoms in a gaseous state are converted into gaseous ions with +1 charge

Question 7

Define second ionisation energy

Answer 7

Removal of a second electron

Question 8

Define first electron affinity

Answer 8

Enthalpy change when 1 mole of gaseous atoms form ions with -1 charge

Question 9

Define the second electron affinity

Answer 9

Gain of a second electron

Question 10

Define enthalpy of lattice formation

Answer 10

Enthalpy change when 1 mole of solid ionic compound is formed from gaseous ions

Question 11

Define enthalpy of lattice dissociation

Answer 11

Enthalpy change when 1 mole of solid ionic compound dissociate into gaseous ions

Question 12

Define standard enthalpy of hydration

Answer 12

Enthalpy change when 1 mole of gaseous ions dissolves completely in water

Question 13

Define standard enthalpy of solution

Answer 13

Enthalpy change when 1 mold of solute dissolves completely to form solution at infinite dilution

Question 14

What is the order of reaction in the born barber cycle?

Answer 14

. Enthalpy of formation 
. Enthalpy of atomisation
. Ionisation energy 
. Electron affinity 
. Enthalpy of lattice formation

Question 15

q = m x c x change in T

Answer 15

Enthalpy change = mass x specific heat capacity x change in temperature

Question 16

Describe how you would use a calorimeter

Answer 16

Burn a fuel to heat a known mass of water and measure the temp change.

Question 17

State Hess’s law

Answer 17

Enthalpy change for a chemical reaction is the same, whatever route is taken from reactants to products