1
the enthalpy of [something]
The enthalpy of the reaction is measured at constant pressure.
反应的焓在恒压下测量。
焓
enthalpies — plural of enthalpy
先理解核心含义，再看它在真实句子里的用法。
焓
a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure
The enthalpy of the reaction is measured at constant pressure.
反应的焓在恒压下测量。
(热力学)等于系统内能加上其体积和压力乘积的热力学量
(thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure
In chemistry class, we calculated the enthalpy change of the reaction to see whether it released heat.
化学课上，我们计算了反应的焓变，以判断它是否放热。
AI contextual example
Engineers often measure the enthalpy of steam to improve the efficiency of a power plant.
工程师们常常测量蒸汽的焓，以提高发电厂的效率。
AI contextual example
The table lists the enthalpies of several common substances at room temperature.
该表列出了几种常见物质在室温下的焓值。
AI contextual example
enthalpy is the amount of energy in a system capable of doing mechanical work
焓是系统中能够做机械功的能量总量。
WordNet
The enthalpy of the reaction is measured at constant pressure.
反应的焓在恒压下测量。
We calculated the enthalpy of the gas.
我们计算了气体的焓。
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。
Not this
The entropy change of the reaction is -92 kJ/mol.
Use this
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）。
Not this
In constant pressure, the enthalpy change equals the heat absorbed.
Use this
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。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
焓变
The enthalpy change of this reaction is negative.
这个反应的焓变为负。
标准焓
Chemists measure standard enthalpy under standard conditions.
化学家在标准条件下测量标准焓。
生成焓
The enthalpy of formation of water is well documented.
水的生成焓有充分记录。
反应焓
We calculated the enthalpy of reaction from the data.
我们根据数据计算了反应焓。
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。
汽化焓
Water has a high enthalpy of vaporization.
水的汽化焓很高。
Use enthalpies naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
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”。
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。
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/。
Dictionary facts from ECDICT, WIKTIONARY.