Energetics Flashcards
What is the definition of enthalpy?
A measure of the heat content of a substance
What is the definition of enthalpy change?
The energy change at a constant pressure
What is the definition of endothermic?
A reaction where at the end of the reaction, energy has been taken in.
What is the definition of exothermic?
A reaction where at the end of the reaction, energy has been given out.
What is the definition of activation energy?
The minimum amount of kinetic energy that particles need to react
What is the definition of standard enthalpy of formation?
The enthalpy change when 1 mole of a compound is formed from its elements with all substances in standard states under standard condition
What is the definition of standard enthalpy of combustion?
The enthalpy change when 1 mole of a compound is completely burnt in oxygen under standard conditions and all the reactants and products in their standard states
What is the definition of standard enthalpy of reaction?
The enthalpy change for a reaction with the quantities shown in the chemical equation. this means that the value should always be quoted along with the equation
What is the definition of standard enthalpy of neutralisation?
The enthalpy change when 1 mole of water is formed in a reaction between an acid and alkali under standard conditions
What is the definition of specific heat capacity?
The amount of heat energy it takes to raise the temperature of 1g of a substance by 1 degrees C
What is the equation to calculate the energy change?
Energy change = massspecific heat capacitychange in temperature
How do you calculate the heat produced?
Heat = energy change/moles
How do you calculate the number of moles?
Number of moles = mass/Mr
What is Hess’s Law?
The enthalpy change for a reaction is independent of the route taken
How can you calculate the overall enthalpy changes from enthalpy changes of formation?
Enthalpy change = Sum(change in the enthalpy of formation of products) - Sum(change in the enthalpy of formation of reactants
