8) How many moles of B are present at 40. s? A) 0.18 B) 0.070 C) 0.124 D) 0.054 E) 7.8times 10^-3 Answer:B 9) How many moles of B are present at 30 s? A 2.4times 10-3 B) 0.15 C) 0.073 D) 1.7times 10-3 E) 0.051 Answer: E

To determine the number of moles of B present at 40 s, we need to refer to the graph provided in the question. According to the graph, the number of moles of B at 40 s is 0.070. Therefore, the correct answer is B) 0.070.<br /><br />To determine the number of moles of B present at 30 s, we need to refer to the graph provided in the question. According to the graph, the number of moles of B at 30 s is 0.051. Therefore, the correct answer is E) 0.051.