Enthalpy Change

Question 1

Thermochemistry

Answer 1

The study of enthalpy changes during chemical reactions

Question 2

Enthalpy

Answer 2

A measure of the heat content of a substance. The symbol H

Question 3

Enthalpy change

Answer 3

Delta H
Change in heat content at a constant pressure
Happens under standard conditions

Question 4

Standard conditions

Answer 4

100kPa

298K

Question 5

Endothermic

Answer 5

More energy being taken in to the reaction to break bonds than is given out

Question 6

Exothermic

Answer 6

More energy being produced be forming bonds than is used to break the bonds

Question 7

Standard enthalpy change of formation

Answer 7

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

Question 8

Standard enthalpy change of combustion

Answer 8

enthalpy change when 1 mole of a substance is completely burned in oxygen with all reactants and products in standard states under standard conditions

Question 9

Enthalpy formation of an element

Answer 9

0 by definition

Question 10

Enthalpy change of neutralisation

Answer 10

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