Read the elapsed time on the stopwatch and answer the questions. a. in which digit is there the least amount of confidence? b. how many significant figures does this measurement have?

The first-order reaction a→2b+c has rate constant 0.538 s−1. if the initial concentration of a is 0.867 mol l−1, what is the half-life of the reaction in seconds? remember to use correct significant figures in your answer (round your answer to the nearest hundredth). do not include units in your response.