Energetics I

Question 1

Define the standard enthalpy change of reaction

Answer 1

The change in enthalpy measured at 100kPa and a stated temperature, usually 298K, when a reaction occurs in the molar quantities shown in the chemical equation under standard conditions.

Question 2

The enthalpy of the reactants is greater than the enthalpy of the products in a certain reaction.

Is this reaction exothermic or endothermic?

Answer 2

The reaction is exothermic.

Question 3

Define the standard enthalpy change of combustion

Answer 3

The change in enthalpy measured at 100kPa and a stated temperature, usually 298K, when one mole of a substance is completely burned in oxygen.

Question 4

Define the Standard enthalpy change of formation:

Answer 4

The change in enthalpy measured at 100kPa and a stated temperature, usually 298K, when one mole of a substance is formed from its elements.

Question 5

Define the Standard enthalpy of neutralisation

Answer 5

The change in enthalpy measured at 100kPa and a stated temperature, usually 298K, when when an acid and alkali react together under standard conditions to form 1 mole of water.

Question 6

Define Specific heat capacity

Answer 6

The amount of energy needed to raise a temperature of 1 g of a substance by ​ 1 degree.

Question 7

State Hess’s law

Answer 7

The total enthalpy change is independent of the reaction pathway taken.

Question 8

Bond Dissosciation Enthalpy

Answer 8

Amount of energy required to break 1 mole of the stated bond in the gas phase.