Return to Blog Homepage

PCAT Chemical Processes – Rate Law for Elementary Reaction

  • by Sam
  • Apr 19, 2018
  • PCAT Question of the Day

The reaction CO (g) + NO3 (g) → CO2 (g) + NO2 (g) is an elementary reaction. Which of the following accurately gives the rate law for this process?

Click for Explanation

A is correct. The rate law of an elementary reaction can be determined from examining the balanced reaction. Only reactants are included in rate laws, but products are not, allowing us to eliminate Choices C and D. (Do not confuse rate laws with equilibrium expressions!) Each reactant listed in a rate law should be raised to the power of its coefficient, which is 1 here for both reactants. The 3 in NO3 is a subscript, not a coefficient, so that term should not be cubed (eliminate Choice B).

Related Post

Submit a Comment

Search the Blog

Free Consultation

Interested in our Online MCAT Course or one of our One-on-One MCAT Tutoring packages? Set up a free consultation with one of our experienced Academic Managers!

Schedule Now

Popular Posts

Free MCAT Practice Account

Need 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

Sign-up for our newsletter!