3.4 enthalpy changes

Question 1

endothermic

Answer 1

energy is transferred from the surroundings to the system +

Question 2

exothermic

Answer 2

energy is transferred from the system to the surroundings -

Question 3

average bond enthalpy

Answer 3

energy required to break one mole of a particular bond in a range of substances

Question 4

specicif heat capacity equation and units

Answer 4

Question 5

Hess’ law

Answer 5

the total enthalpy change in a chemical reaction is independent of the route by which the chemical reaction takes place as long as the initial and final conditions are the same.

Question 6

activation energy

Answer 6

the minimum amount of energy needed for reactant molecules to have a successful collision and start the reaction

Question 7

hess’ law for combustion

Answer 7

Question 8

hess’ law for formation

Answer 8

Question 9

enthalpy change of combustion

Answer 9

enthalpy change when one mole of a substance is completely burnt in oxygen

Question 10

enthalpy change of formation

Answer 10

enthalpy change when one mole of a substance is formed from elements

Question 11

enthalpy change of neutralisation

Answer 11

enthalpy change when one mole of water is formed from neutralisation

Question 12

standard conditions

Answer 12

100kPa and 298k

Question 13

specific heat capacity

Answer 13

amount of energy needed to increase the temperature of 1g of a substance by 1K