Return to Blog Homepage

MCAT Chemistry Question — Mercury Meniscus

  • by John
  • Dec 16, 2014
  • MCAT Blog, MCAT Chemistry, MCAT Question of the Day

Mercury is a liquid with greater cohesive than adhesive forces, when placed in a glass tube (such as in a barometer). The meniscus formed with such a liquid would appear:

 

A) Convex

B) Flat

C) Concave

D) Irregular

 

 

Explanation

 

The classic concave meniscus that we see with water in a graduated cylinder is because the water has greater adhesive forces between the water and the glass than cohesive forces (the water sticking to itself). Since the water “wants” to stick to the walls of the container, it crawls up the sides of the container a bit to get more surface area sticking to the cylinder. Those higher edges create that classic concave meniscus.

 

The situation described in the question is the reverse of that – stronger cohesive forces. So the meniscus we see would be the opposite: convex instead of concave. Thus, the answer is (A) Convex.

 

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 Advisor using the form below. No obligation, just expert advice.

Schedule My Free Consultation

Submit a Comment