How many half-lives are required for the concentration of reactant to decrease to 3.125 % of its original value for a first-order reaction

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass

What is the mass of 4 molecules of co2

Voltaic cells produce a positive overall charge. what does this indicate? a. the reaction is likely to be endothermic. b. the reaction is spontaneous. c. the reaction is not likely to occur. d. the reaction is not spontaneous.