Alevel有机化学一定要掌握的11个定义！

Hydrocarbon:

A compound consisting of hydrogen and carbon only

这个概念很好理解，只有H和O组成的化合物，比如CH4.

Saturated:

Carbon chains that contain the maximum number of hydrogens per carbon; only single C-C bonds

饱和键，化合物中C-C之间都是单键

Unsaturated:

Carbon chains that don’t have the maximum number of hydrogens per carbon; contain C=C double bonds不饱和键，C和C之间是双键（Double bond）或者三键（Triple bond）

Empirical formula:

The simplest whole number ratio of atoms of each element in the compound

最简式；比如C2H6的Emprical fomula是CH3

Molecular formula:

The actual number of each type of atom in the compound

分子式；明确的给出每一种原子的个数，比如C2H6O

General formula:

Algebraic formula for a homologous series

通式；表示同一类化合物分子组成的公式，比如alkane，烷烃类的通式为CnH2n+2

Structural formula:

Shows the minimal detail of the arrangement of atoms in a molecule结构式

Displayed formula:

Shows all the covalent bonds present in a molecule

展示所有的原子和键

Skeletal formula:

Shows the simplest organic formula of the carbon skeleton and associated functional groups

Homologous Series:

Families of organic compounds with the same functional group and general formula

同系物；是指结构相似、通式相同、分子组成相差若干个“CH2”原子团的有机化合物；是同一类物质（含有相同且数量相等的官能团。比如：CH4；C2H6；C3H8

Functional group:

The atom/group of atoms which provide the chemical properties of a substance

官能团，是决定有机化合物的化学性质的原子或原子团。常见官能团碳碳双键、碳碳三键、羟基、羧基、醚键、醛基、羰基等。有机化学反应主要发生在官能团上，官能团对有机物的性质起决定作用，如—X、OH、-CHO、-COOH、-NO2、-SO3H、-NH2、RCO-。