Select all of the correct statements about reaction rates from the choices below. The lower the rate of a reaction the longer it takes to reach completion. As a reaction progresses its rate goes down. Concentrations of homogeneous catalysts have no effect on reaction rates. Reaction rates always increase as masses of solid reactants increase. Reaction rates increase as concentrations of homogeneous catalysts increase. Reaction rates decrease with increasing temperature. The slowest step in a reaction is called the rate-determining step.