Unit 1 Section 4: Energetics

Question 1

What is standard enthalpy change of formation?

Answer 1

The enthalpy change when 1 mole of compound is formed from its elements in their standard states under standard conditions.

Question 2

What is standard enthalpy change of combustion?

Answer 2

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

Question 3

What is standard enthalpy change of reaction?

Answer 3

The enthalpy change when a reaction occurs in the molar quantities shown in the chemical equation, under standard conditions with all reactants and products in their standard states.

Question 4

In what type of reaction are bonds broken?

Answer 4

Endothermic

Question 5

In what type of reaction are bonds formed?

Answer 5

Exothermic

Question 6

State the meaning of the term “rate of reaction”.

Answer 6

The change in concentration of a substance in a given time