CHAPTER 9 - ENTHALPY Flashcards
What is enthalpy
A measure of the heat energy in a chemical system (or the energy stored within bonds)
What is the equation to measure changes in enthalpy
Change in H= H(products) - H(reactants)
What is conservation of energy law
Energy cannot be created or destroyed, only transferred
What is an exothermic reation
A reaction which transfers heat energy from the system to the surroundings
What is an endothermic reaction
A reaction which transfers heat energy from the surroundings to the system
What is the standard enthalpy change of formation
Enthalpy change that takes place when one mole of a compounds is formed from its elements under standard conditions, with all reactants and products in their standard states
What is the enthalpy of combustion
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions, with all reactants and products in their standard states
What is the enthalpy of neutralisation
The enthalpy change that accompanies the reaction of an acid by a base to form one mole of H2O, under standard conditions with all reactants and products in their standard states
What is activation energy
Minimum energy required for the reaction to take place,
Input to break bonds which is a barrier to a reaction
What are the standard conditions
Pressure - 100kPA (~1 atm)
Temp - 298K; 25 degrees Celsius
Conc - 1 mol dm-3 (only solutions)
Standard states
What is enthalpy of reaction
Enthalpy change that accompanies a reaction in the molar quantities shown in a chemical equation under standard conditions, with all reactants and products in their standard states
ENERGY CHANGE
