含义Meaning
单位体积溶液中所含溶质的物质的量，单位 mol/L。
Amount of solute per unit volume of solution, in mol/L.
符号说明Symbols
| 符号Symbol | 含义 Meaning | 单位 Unit |
|---|---|---|
| \(c_\mathrm{B}\) | 溶质 B 的物质的量浓度molar concentration of solute B | mol·L⁻¹ |
| \(n_\mathrm{B}\) | 溶质的物质的量amount of solute | mol |
| \(V\) | 溶液体积（不是溶剂体积）volume of solution (not of solvent) | L |
推导Derivation
按定义：溶质物质的量除以溶液体积。
By definition: amount of solute divided by solution volume.
配制溶液时先求 \(n = cV\)，再由 \(m = nM\) 称量，定容到容量瓶刻度。
To prepare a solution compute \(n = cV\), weigh \(m = nM\), and make up to the mark in a volumetric flask.
离子浓度按化学式计量：0.1 mol/L Na₂SO₄ 中 c(Na⁺) = 0.2 mol/L。
Ion concentrations follow the formula: 0.1 mol/L Na₂SO₄ has c(Na⁺) = 0.2 mol/L.
适用条件与局限Assumptions & limitations
V 是溶液体积，随温度变化，所以 c 随温度略变（水约 0.02%/K）；精密工作用质量摩尔浓度 b。
V is the solution volume and changes with temperature, so c drifts slightly (~0.02 %/K for water); precise work uses molality b.
弱电解质部分电离、强电解质高浓度下离子缔合，实际“有效浓度”需用活度表示。
Partial dissociation and ion pairing mean the effective concentration is the activity, not c.
例题Worked example
把 5.85 g NaCl 溶于水配成 250 mL 溶液：n = 0.100 mol，c = 0.100/0.250 = 0.400 mol/L。
5.85 g NaCl made up to 250 mL: n = 0.100 mol, c = 0.400 mol/L.