The reactant concentration in a zero-order reaction was 5.00 × 10^(-2) M after 190 s and 2.00 × 10^(-2) M after 400 s. What is the rate constant for this reaction? Express your answer with the appropriate units.
a) 2.63 × 10^(-4) M/s
b) 1.05 × 10^(-4) M/s
c) 2.63 × 10^(-3) M/s
d) 1.05 × 10^(-3) M/s
