Word · Frequency #13637
enthalpy
焓
a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure
- 1.
(thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure
(热力学)等于系统内能加上其体积和压力乘积的热力学量
(热力学)等于系统内能加上其体积和压力乘积的热力学量；焓；[化] 焓
In use
In chemistry class, we calculated the enthalpy change of the reaction to see whether it released heat.
Engineers often measure the enthalpy of steam to improve the efficiency of a power plant.
The table lists the enthalpies of several common substances at room temperature.
enthalpy is the amount of energy in a system capable of doing mechanical work
the enthalpy of [something]
The enthalpy of the reaction is measured at constant pressure.
反应的焓在恒压下测量。
measure/calculate the enthalpy
We calculated the enthalpy of the gas.
我们计算了气体的焓。
the enthalpies of [plural noun]
enthalpy 的复数形式为 enthalpies。
The enthalpies of the two compounds differ significantly.
这两种化合物的焓差异显著。
Common mistakes
The entropy change of the reaction is -92 kJ/mol.The enthalpy change of the reaction is -92 kJ/mol.
Entropy（熵）和enthalpy（焓）是热力学中两个不同的状态函数：熵衡量体系的混乱度，焓衡量恒压下的热含量。若要说明反应的热效应，应为enthalpy change（焓变），不能用entropy change（熵变）。
In constant pressure, the enthalpy change equals the heat absorbed.At constant pressure, the enthalpy change equals the heat absorbed.
表示“在……条件下”时，英语用介词at，如at constant pressure（在恒压下），而in通常表示“在……里”。中文的“在恒压下”容易直译为in，但正确搭配是at。
Connections
Collocations
- enthalpy change
- 焓变
- The enthalpy change of this reaction is negative.这个反应的焓变为负。
- standard enthalpy
- 标准焓
- Chemists measure standard enthalpy under standard conditions.化学家在标准条件下测量标准焓。
- enthalpy of formation
- 生成焓
- The enthalpy of formation of water is well documented.水的生成焓有充分记录。
- enthalpy of reaction
- 反应焓
- We calculated the enthalpy of reaction from the data.我们根据数据计算了反应焓。
- enthalpy of combustion
- 燃烧焓
- The enthalpy of combustion of methane is -890 kJ/mol.甲烷的燃烧焓为-890千焦/摩尔。
- enthalpy of vaporization
Learner notes
Memory Tip
记忆联想：焓的符号 H 取自 enthalpy 首字母，公式 H = U + PV（内能 + 压强×体积），可记作“H 含 PV”。
Context & Register
语域：formal 常见场景：热力学、物理化学、工程热力学 焓是热力学中的专业术语，通常出现在学术论文、教材或工程文献中，属于正式的书面语。日常口语中很少使用。
Pronunciation & Spelling
没有与 enthalpy 完全押韵的常用词。hypothalamus 有相同的重读 /θæl/ 但结尾不同；alpine 和 scalpel 只是拼写有相似片段；puppy、happy、copy 只有词尾 -py 拼写相同。注意 enthalpy 读 /enˈθælpi/，不要把结尾读成 /paɪ/。
Learn the forms together
页面下方列出了常见词形变化。学习时注意它们在句子中的语法位置。
Dictionary facts from ECDICT, WIKTIONARY.