Enthalpy Changes + calorimetry

Question 1

Enthalpy change calculation

Answer 1

Enthalpy change = change in heat content at constant pressure

Question 2

Standard conditions

Answer 2

100kpa and 278 K

Question 3

standard enthalpy change
△ f H°

Answer 3

Enthalpy change when one mole of a substance is formed from its constituent elements with all the reactants and all products in standard state under standard conditions.

Question 4

Standard enthalpy change of combustion
△ c H°

Answer 4

Enthalpy change when 1 mole of a substance is burned in oxygen with all reactants and products in standard state under standard conditions.

Question 5

standard enthalpy change of neutralisation
△ neut H°

Answer 5

Enthalpy change when 1 mole of water is formed in reaction between an acid and alkali under standard conditions.

Question 6

EQUATION

Answer 6

q = mc△T
q = quantum = energy required
m = mass
c = specific heat capacity
△T = change in temp

Question 7

Energy required (q) =

Answer 7

mass of liquid heated (m)
*
specific heat capacity of liquid (c)
*
temperature rise of liquid (△T)

Question 8

△H (enthalpy change) =

Answer 8

q / moles in reaction
if reaction is exothermic, the temperature would increase and the value of the enthalpy change MUST be a negative