Energetics

Question 1

What are standard conditions

Answer 1

100 kPa

298k

Question 2

Define endothermic

Answer 2

Positive energy change

Question 3

Define exothermic

Answer 3

Negative energy change

Question 4

Define enthalpy change of combustion

Answer 4

Enthalpy change of one mole of a substance burnt completely in excess oxygen to form CO2 and water in standard conditions and standard states

Question 5

Enthalpy change of neutralisation

Answer 5

Enthalpy change of an acid base reaction producing one mole of water where all reactant are in standard states/ conditions

Question 6

Calculating enthalpy change of neutralisation

Answer 6

-q/ mol of water

Question 7

Mean bond enthalpy

Answer 7

Enthalpy change requires to break one mole of bonds under standard conditions with all reactants in the gaseous state
(AVERAGE)

Question 8

General equation for energy change

Answer 8

Total energy absorbed- total energy released

Question 9

Arrow direction in enthalpy of combustion

Answer 9

Away from reactants/ products

Question 10

Arrow direction in enthalpy of formation

Answer 10

Towards the reactants and products

Question 11

Problems with calorimetry

Answer 11

Heat loss to surrounding, calorimeter should be insulated
Sometimes combustion is incomplete, less energy given out
Flammable liquids usually volatile, lost fuel to evaporation

Question 12

Gibbs free energy equation

Answer 12

Delta G= Delta H -(T x Delta S)