Enthalpy Change

Question 1

What is the ideal gas equation?

Answer 1

Pressure (pa) x volume (m3) = Moles x gas constant (8.314) x temperature (K)

Question 2

What is the definition of enthalpy change?

Answer 2

The heat transferred in a reaction at constant pressure

Question 3

Why are bond enthalpies not exact?

Answer 3

The energy needed to break 1 mole of bonds in the gas phase is averaged over many different compounds

Question 4

How can you define bond length?

Answer 4

The distance between two nuclei where the attractive and repulsive forces balance each other

Question 5

Standard enthalpy change of reaction?

Answer 5

The enthalpy change when the reaction occurs in the molar quantities shown in the chemical reaction under standard conditions

Question 6

Standard enthalpy change of formation?

Answer 6

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

Question 7

Standard enthalpy change of combustion?

Answer 7

The enthalpy change when 1 mole of a substance is completely burned in oxygen under standard conditions

Question 8

What are the standard conditions?

Answer 8

298k
25 degrees
100kpa