Standard Conditions

Question 1

What does the enthalpy change of a chemical reaction depend on?

Answer 1

Temperature, pressure, physical state and moles of reactants

Question 2

What are the standard conditions?

Answer 2

298K (25C)
1atm (100KPa)
1 mol dm-3

Question 3

Standard enthalpy of reaction definition?

Answer 3

The heat energy change at constant pressure when the amounts of reactants shown in the equation reach under standard conditions to give the products in their standard states

Question 4

Bond enthalpy definition?

Answer 4

The change in energy when one mole of gaseous covalent bonds is broken

Question 5

What is the standard enthalpy of neutralisation definition?

Answer 5

The enthalpy change when 1 mole of water is formed from the reaction of an acid with a base

Question 6

Enthalpy change of formation definition?

Answer 6

The change in energy when one mole of a compound is formed from its elements in their standard states

Question 7

Enthalpy change of combustion definition?

Answer 7

The change in energy when 1 mole of a substance is burnt completely in oxygen

Question 8

Hess’s law?

Answer 8

The enthalpy change during a chemical change is independent of the steps taken

Question 9

How accurate is the experiemental value for solution calorimeters?

Answer 9

Heat loss to the surroundings other than the water
Incomplete combustion- CO and C being produced instead of CO2
Evaporation of methanol from the wick
Non-standard conditions