Final answer:
The half-life of a first-order reaction can be calculated using the formula t1/2 = 0.693/k, where k is the rate constant. In this case, since the reaction is complete at the end of 43 minutes, each half-life of the reaction is 4.3 minutes.
Step-by-step explanation:
The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction. The formula for calculating the half-life of a first-order reaction is t1/2 = 0.693/k, where k is the rate constant.
Since the question states that the first-order reaction is complete at the end of 43 minutes, we can use this information to find the value of the rate constant. When a reaction is complete, the concentration of the reactant has decreased to zero. In a first-order reaction, the concentration decreases by half during each half-life. Since the reaction is complete at the end of 43 minutes, we can say that the concentration has decreased by a factor of 2^10 (2 raised to the power of 10) since 43 / 43 = 10. Therefore, the length of each half-life is 43 minutes divided by 10, which equals 4.3 minutes.