Enthalpy and Hess' cycle

Question 1

enthalpy(H)

Answer 1

all the heat energy that is stored in a chemical system

Question 2

enthalpy change (ΔH)

Answer 2

products - reactants

Question 3

enthalpy profile

Answer 3

y = enthalpy
x = progress of reaction

Ea = reactants to peak
ΔH = reactants to products

Question 4

standard enthalpy change (ΔH°)

Answer 4

.298 K
.100 kPa
.1 mol
.all chemicals in their standard states

Question 5

standard enthalpy change of combustion (ΔcH°)

Answer 5

when one mole of a substance reacts completely with oxygen under standard conditions

Question 6

standard enthalpy change of neutralisation (ΔnH°)

Answer 6

.one mole of water is formed in a neu reaction under standard conditions

Question 7

standard enthalpy change of formation (ΔfH°)

Answer 7

when one mole of a compound is formed from its elements under standard conditions

Question 8

standard enthalpy change of reaction (ΔrH°)

Answer 8

when a reaction takes place in the molar quantities shown by the balanced chemical equation under standard conditions

Question 9

thermal energy

Answer 9

q = mcΔT

q = energy change in J
m = mass of water in g
T = temp change of water

Question 10

calculating ΔcH° and ΔrH°

Answer 10

thermal energy(KJ)/num of moles

.always negative