rate and extent of chemical changes

calculating rate of reaction

amount of reactant or product formed / time

rate of reaction graphs

• more steep = faster reaction

• when line goes flat = reaction has stopped bcz one of the reactants is limiting

activation energy

the minimum energy needed for the particles to collide with sufficient energy

5 factors affecting rate

• temp = particles gain kinetic energy, move faster, more freq collisions

• conc = more particles in the same volume means more freq collisions

• pressure = particles are closer together = more freq collisions

• SA = breaking a solid into smaller pieces increases area for collision = more freq

• catalyst = provides an alternative pathway with a lower activation energy

reversible reactions

• if its endo in one direction it must be exo in the opposite direction

• same amount of energy is transferred in each direction

• reaches an equilibrium in a closed system

equilibrium

• when a reversible reac happens in a closed system it reaches equilibrium

• forward and reverse reaction happens at the exact same rate

• conc of all substances stay constant (not necessarily equal)

Le chateliers principle

if u change the conditions of a system at equilibrium, the system will shift to counteract the change

equilibrium = increase in conc

equilibrium shift to the side that uses up the added substance

equilibrium = increase in temp

• equilibrium shifts in the endothermic direction to absorb heat

equilibrium = decrease temp

equilibrium shifts in the exothermic direction to release heat

equilibrium = increase pressure

equilibrium shifts to the side with the fewest moles of gas

equilibrium = decrease in pressure

equilibrium shift to the side with the most moles of gas

catalyst and equilibrium

• it speeds us both the forward and reverse reaction equally

• so it doesn’t change the position of the equilibrium

• it just helps reach an equilibrium faster