Topic 8- Energetics I Flashcards
What is meant by the standard enthalpy change of formation?
The enthalpy change when one mole of a substance is formed from its elements in their standard states at 100kPa and 298K
What is Hess’s Law
He states that the enthalpy change of a reaction is independent of the path taken provided the initial and final conditions remain the same
What direction do the arrows go if there is data for standard enthalpy of formation?
Arrows go up
What is the standard enthalpy change of neutralisation?
The enthalpy change when one mole of water is produced by the neutralisation of an acid and an alkali at 100kPa and 298K
What is the enthalpy change of combustion?
The enthalpy change when one mole of a substance is completely burned in oxygen at 100kPa and 298K
What is bond enthalpy?
The enthalpy change when one mole of a bond in the gaseous state is broken
What is meant by mean bond enthalpy?
The enthalpy change when one mole of a bond, averaged out over many different molecules, is broken
What is the standard enthalpy change of reaction?
The enthalpy change when the number of moles of substances in the equation as written react
What is an exothermic process?
When heat energy is transferred from the system to the surroundings
What is an endothermic process?
When heat is transferred from the surroundings to the system
