Energetics Flashcards
What is a exothermic process ?
When energy is released during the reaction ( delta h is negative)
What is a endothermic reaction ?
when energy is taken in during the reaction ( delta h is positive)
What is enthalpy change ?
Change in heat energy at constant pressure.
What are standard conditions ?
100kPa
25 degree c
1 moldm^-3 concentration
When breaking or making bonds what are the changes energy ?
Breaking bonds takes in energy (endo)
Making bonds releases energy (exo)
What is activation energy ?
The minimum amount of energy required for a reaction to occur
What is bond enthalpy ?
The energy required to break one mole of covalent bond into gaseous atoms averaged over a range of compounds
What is the standard enthalpy of formation ?
When one mole is formed of a substance under standard conditions with all products and reactants being in their standard states.
What is the standard enthalpy of combustion ?
the enthalpy change when mole of a substance is burnt in excess oxygen at standard conditions and all products and reactants in their standard states.
What is hess’ law ?
The enthalpy change for a chemical reaction from products to reactants is the same no matter the path taken
What is the formulae used in calorimetry ?
Q = m C T
Q is energy
m is mass of water
c is specific heat capacity of water
t is temperature change
delta h = 0.001xQ / n
delta h is change in heat energy
q is energy
n is number of moles
