reactions Flashcards
2exothermic reactions
energy/ heat is released from a reaction to the surroundings leading to an increase in temperature examples: sport packs combustion rusting of iron
endothermic reactions
energy/heat is absorbed in a reaction from the surroundings leading to a decrease in temperature
examples:
melting ice cubes
evaporating liquid water
collision theory
For a chemical reaction to occur, the reactant molecules must collide with enough energy
activation energy
the amount of kinetic energy needed for a reaction to occur
limitation of particle theory
particle theory assumes that all particle are the same in substances
moles (mols)
used to measure the amount of a substance in a unit called ‘the mole’. This is a convenient way of counting atoms. It allows chemists to make predictions about the masses of different substances that are involved in reactions.
moles avogadro
one mole is the Avogadro number of particles
calculate the number of moles
Divide the known mass of the compound by its molar mass to calculate the number of moles.
redox reaction
Redox reaction is an abbreviation of “oxidation-reduction reaction,
reversible reactions
a +b = c + d
conservation of energy
energy is conserved during chemical reactions
the energy released/absorbed by the forwards reaction is equal to the energy released/absorbed by the backwards reaction
equilibrium
the forward and backwards reaction are happening at the same rate
what effects the equilibrium
concentration temperature
how does concentration affect an equilibrium
if pressure is increased the position of the equilibrium moves in the direction of the fewest moles of gas
how does temperature affect an equilibrium
if temp is increased then the position of the equilibrium is moved towards the endothermic reaction
if temp is decreased the position will move towards the exothermic reaction
