Passage II
Primary amines (PAs) are compounds containing an amino (NH2) group bound to a hydrocarbon chain (a group made up of C and H atoms). Table 1 lists, for each of 5 PAs, the chemical formula, molecular mass (mass of 1 molecule) in atomic mass units (amu), melting point (MP), and boiling point (BP).
Table 2 lists, for each of the 5 PAs, the flash point (the lowest temperature at which a flammable mixture is formed in the air above a liquid) and the temperature at which the vapor pressure (the pressure exerted by a vapor in equilibrium with its liquid state) equals 0.1 kPa, 1 kPa, 10 kPa, and 100 kPa.
Tables adapted from W. M. Haynes, ed., CRC Handbook of Chemistry and Physics on CD-ROM, Version 2011. ©2011 by CRC Press, LLC.
10. Consider the PA ethanamine, CH3CH2NH2. Based on Table 1, the molecular mass of ethanamine is closest to which of the following?
Your Answer is
Correct Answer is G
Explanation
The chemical formulas of the first two PAs in Table 1 differ by one CH2, so the molecule mass of one CH2=73-59=14; the new PA in the question stem One less CH2 than 1-propanamine, so the molecule mass of ethanamine=59-14=45