Energetics

Question 1

What is enthalpy change?

Answer 1

Heat or energy change under constant pressure

Question 2

What are the conditions for standard enthalpy change?

Answer 2

298 K
100 kPa

Question 3

What does exothermic mean and what is the enthalpy change?

Answer 3

Heat given out - negative enthalpy change

Question 4

What does endothermic mean and what is the enthalpy change?

Answer 4

Heat taken in - positive enthalpy change

Question 5

What is the unit for enthalpy change?

Answer 5

kJ/mol

Question 6

What is enthalpy change of formation?

Answer 6

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

Question 7

What is enthalpy change of combustion?

Answer 7

Enthalpy change when 1 mole of a compound is burned completely in O2 with all reactants and products in standard states under standard conditions

Question 8

What is bond enthalpy?

Answer 8

Enthalpy change that takes place when breaking by homolytic fission 1 mol of a given bond in the molecules of a gaseous species

Question 9

What is averge bond enthalpy?