enthalpy

Question 1

define enthalpy

Answer 1

the measure of the heat energy in a chemical system

Question 2

how do you calculate enthalpy change?

Answer 2

enthalpy change = H(products) - H(reactants)

Question 3

define conservation of energy

Answer 3

energy cannot be created or destroyed

Question 4

exothermic change

Answer 4

heat out of the system to the surroundings (negative enthalpy change)

Question 5

endothermic change

Answer 5

heat into the system from the surroundings (positive enthalpy change)

Question 6

activation energy

Answer 6

the minimum energy required for a reaction to take place

Question 7

standard conditions

Answer 7

100kPa
298K
1 mol dm-3

Question 8

standard state

Answer 8

the physical state of a substance under standard conditions (RTP)

Question 9

enthalpy changes of reaction

Answer 9

the enthalpy change that accompanies a reaction in the molar quantities shown in a chemical equation under standard conditions

Question 10

enthalpy of formation

Answer 10

enthalpy change when 1 mole of a compound is formed from its constituent elements under standard conditions with everything in its standard state

Question 11

enthalpy of combustion

Answer 11

enthalpy change when 1 mole of fuel reacts completely with oxygen under standard conditions with everything in its standard state

Question 12

enthalpy of neutralisation

Answer 12

the energy change that accompanies the reaction of an acid by a base to form one mole of H2O (l) under standard conditions with everything in its standard state