Energetics key terms Flashcards
(12 cards)
What is enthalpy?
It is a measure of the heat content of a substance.
What is enthalpy change?
The amount of heat energy that is taken in or out during any change in a system.
What are the standard conditions?
- 298K
- 100kPa
What is activation energy?
It is the minimum energy required to start a reaction by the breaking of bonds.
What is the definition of enthalpy change of formation?
Enthalpy change when one mole of a substance is made from its constituent elements in their standard states under standard conditions.
What is the definition for enthalpy change of combustion?
Enthalpy change when one mole of a substance is burned completely in oxygen under standard conditions.
What is hess’ law?
The total enthalpy change is independent of the route taken by which the chemical change takes place, provided the initial and final conditions are the same.
What is enthalpy of hydration?
The temperature is taken every after 30 seconds before mixing the reactants.
What is mean bond enthalpy?
The enthalpy needed to break one mole of covalent bonds into gaseous atoms, averaged over different molecules.
What are bond enthalpies?
energy needed to make or break a bond
Formula to calculate enthalpy change of formation
products - reactants
Formula to calculate enthalpy change of combustion
reactants - products
