含义Meaning
物体温度改变 ΔT 时吸收或放出的热量。比热容 c 是 1 kg（或 1 g）物质升温 1 K 所需热量；水的比热容很大，4.18 J/(g·K)。
Heat absorbed or released for a temperature change ΔT. Specific heat c is the heat to warm 1 kg (or 1 g) by 1 K; water’s is large, 4.18 J g⁻¹ K⁻¹.
符号说明Symbols
| 符号Symbol | 含义 Meaning | 单位 Unit |
|---|---|---|
| \(Q\) | 热量heat | J |
| \(c\) | 比热容specific heat capacity | J·g⁻¹·K⁻¹ |
| \(C\) | 热容heat capacity | J·K⁻¹ |
| \(C_m\) | 摩尔热容molar heat capacity | J·mol⁻¹·K⁻¹ |
推导Derivation
按定义 \(C = \delta Q/dT\)；若 C 在温度范围内不变，积分得 \(Q = C\Delta T\)。
By definition \(C = \delta Q/dT\); constant C integrates to \(Q = C\Delta T\).
热量计（量热法）：反应放热被溶液和量热计吸收，\(q_\text{反应} = -(c\,m\,\Delta T + C_\text{cal}\Delta T)\)。
Calorimetry: \(q_\text{rxn} = -(cm\Delta T + C_\text{cal}\Delta T)\).
适用条件与局限Assumptions & limitations
不适用于有相变的过程（相变时吸热而温度不变）；热容随温度变化时需积分。
Not across phase changes; integrate if C varies with T.
区分定压 Cp 与定容 Cv：气体两者差别大（\(C_p - C_V = R\)）。
Distinguish Cp and Cv (differ by R for ideal gases).
例题Worked example
把 200 g 水从 20 °C 加热到 100 °C：Q = 4.18×200×80 = 66.9 kJ。
Heating 200 g of water from 20 to 100 °C needs 66.9 kJ.