Most problems ask you to predict boiling points or vapor pressures. Remember this hierarchy (weakest to strongest): Dispersion (London) Forces: In all molecules; stronger in larger, "floppier" atoms. Dipole-Dipole: molecules. Hydrogen Bonding: Only when H is bonded directly to F, O, or N Ion-Dipole:
If you are stuck on a numeric answer, look at the units required (e.g., "kJ"). Ask: What cancels? Example: You need kJ, but you have grams and ( \Delta H_vap ) (J/g). mastering chemistry homework answers chapter 12
"Arrange the following in order of increasing boiling point: Ar, CH₄, H₂O, CH₃Cl." Most problems ask you to predict boiling points
Distinguishing between solutes and solvents in gas, liquid, and solid phases. Hydrogen Bonding: Only when H is bonded directly
) or a pressure at a specific temperature, use the natural log form:
This is where 90% of students request "answers" because the numbers change for each student, but the math doesn't.