The primary amines A and B can donate two hydrogen bonds and accept one (due to the lone pair on N). Generally, for compounds with the same functional group, the higher molecular weight compounds have a higher boiling point due to increased opportunity for intermolecular van der Waals (weak, but better than nothing) interactions. Of course, even though a periodic table is available during the exam with a click of a button, you do not need to calculate the molecular weight since you can quickly determine the number of carbons of the different N-containing structures which easily reveals B as the “heaviest.”
Helpful hint: If all other factors are the same, increased molecular weight means that it is harder to push that molecule into the vapor phase meaning the boiling point would be higher.
The Medical College Admissions Test (MCAT) is a test administered by the Association of American Medical Colleges (AAMC). The test is designed to test your knowledge in three specific sections; physical sciences such as physics and general chemistry, biological sciences and organic chemistry, and verbal reasoning.
How Should I Study?
The MCAT is a rigorous exam that requires months of planning in order to achieve a great score. It is recommended that you begin your study schedule 3 months prior to your exam date. In addition to answering our practice MCAT questions each day, read this article regarding studying for the MCAT from home.
Register for the MCAT.
The first question many people ask is, “when should I take the MCAT?” The general guideline is to take the MCAT the year before you plan to enter medical school. For example, the class of 2018 should take the MCAT sometime before or during the spring/summer of 2013. Your basic science coursework should be complete by this point.