MCAT Chemistry Question — Chemical Reactions
- Aug 26, 2014
- MCAT Question of the Day
3 Q2 + 2 AX4 → 2AX3Q + 2XQ + 2Q–
1. AX3+ Q2→ AX3Q + Q–
2. 2 AX4 + Q2 → AX3Q + Q–
If the second reaction is experimentally determined to be an order of magnitude slower than the first reaction, the researcher can likely conclude that the rate law followed by the hypothetical reaction would be which of the following?
A) R = k[AX4][Q2]
B) R = k [AX4]2[Q2]
C) R = k [AX4]2[Q2]2
D) R = k [AX4]2[Q2]3
The rate law is determined by the slowest step (the rate-determining step). The problem tells you that the second reaction is the slowest step, so it will determine the rate law. The exponents in the rate law match the stoichiometric coefficients of the reagents in the rate determining step. Here, the AX4 has a coefficient of 2 and the Q2 has a coefficient of 1. That matches the exponents in choice (B).
Want more MCAT practice?
We’ve got options for every schedule and learning style!
From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative full-length practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!
Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.
Search the Blog
Free ConsultationSchedule Now
Free MCAT Practice AccountNeed great MCAT practice?
Get the most representative MCAT practice possible when you sign up for our free MCAT Account, which includes a half-length diagnostic exam and one of our full-length MCAT practice exams.Learn More