Final answer:
In a first-order reaction, the fraction of the initial reactant consumed in a given number of half-lives can be calculated using the equation (1/2)^n, where n is the number of half-lives. In this case, with 4 half-lives, the fraction consumed is 1/16 or 0.0625.
Step-by-step explanation:
A reactant R is being consumed in a first-order reaction. The fraction of the initial R consumed in 4.0 half-lives can be calculated using the equation:
Fraction consumed = (1/2)n
Where n is the number of half-lives. In this case, n = 4. Substituting the values into the equation, we get:
Fraction consumed = (1/2)4 = 1/16 = 0.0625
Therefore, the correct answer is A. 0.063.