在ccc竞赛竟然考到四种分子间作用力？

加拿大化学竞赛(Canadian Chemistry Contest)竞赛竟然考到四种分子间作用力？学alevel是不会告诉你的。一般alevel只学到三种分子间作用力：

而在CCC考纲明确要求我们需要掌握4种，并且能够利用这些分子间作用力判断熔沸点和溶解度。

5.11 explain the effect of solutes on the melting point of solid water, using intermolecular forces

根据我在《加拿大化学竞赛CCC复习指导》给大家总结的内容，跟大家补充一下这方面的知识：

Intermolecular forces的定义：

Intermolecular forcesare attractive forces between molecules. They are largely responsible for the observedboiling pointsandsolubilityproperties of molecules.

1. 伦敦力，也叫色散力：

1).London Dispersion:Attraction between molecules that form due to atemporary dipoleon one molecule inducing a temporary dipole inneighboring molecules.

2.偶极-偶极 作用

2).Dipole-Dipole:Attraction between twopolar molecules(dipoles)

3. 氢键

3).Hydrogen Bonding:Attraction between twopolar molecules, specifically one molecule having aH bondeddirectly to an electronegative atom (eg.H-O-, H-N-, HF), and the other having a non-bonding electron pair on anelectronegative atom.

4. 离子偶极作用（这是我们今天提到的！）

4).Ion-Dipole:Attraction between anionand apolar molecule.

这几种力相对强弱如下：

如果你需要判断他们熔沸点的大小，除了知道这些作用力还需要了解这些“趋势(trends)”：

1. Between two molecules of similar mass, the one with thestronger typeof intermolecular force has ahigher boiling point.

2. Between twononpolar moleculesof similar mass, themore extendedmolecule will have thehigher boiling point(more extended amore surface areafor London dispersion interaction).

3. Between twononpolar moleculesof different masses, thelarger moleculewill have thehigher boiling point(larger molecule → more electrons → more polarizability → more London dispersion forces)

相关真题我总结在《加拿大化学思维挑战CCC分类真题》专辑里面：