The concentration of reactants and products and the rate of reaction were measured during a chemical reaction. after the first 3 seconds, the rate of reaction was 1.8 x10−6 m/s. which of the following would explain a lower rate after another 3 seconds? the concentration of reactants increased while the concentration of product decreased. the concentration of reactants decreased while the concentration of product increased. all concentrations of reactants and products decreased. all concentrations of reactants and products increased.