enthalpy

enthalpy — noun

1. in physics and chemistry, the total energy stored in a system that can be releas

1.名詞C2
釋義

in physics and chemistry, the total energy stored in a system that can be released as heat, equal to the sum of its internal energy and the work needed to make room for it against outside pressure; a quantity used to calculate how much heat is absorbed or released during chemical reactions and changes of state.

例句

The chemistry students measured the enthalpy change when sodium hydroxide dissolved in water.

collocation: enthalpy change

Engineers use the enthalpy of steam to design more efficient power plants.

pattern: enthalpy of + noun

同義詞
  • heat content

    less formal lay term that conveys the same idea; used mainly in introductory textbooks

文法句型

enthalpy of + noun phrase

change in enthalpy

用法筆記

Enthalpy is symbolised by the capital letter H. Its value depends only on the current state of the system, not on how the system reached that state. The term is rarely used outside scientific and engineering contexts.

常見錯誤

❌The enthalpy went up, so heat was taken in.' (vague reference)
✅The enthalpy of the system increased by 50 kJ, which means the reaction absorbed heat.
💡Enthalpy is a property of a system, not an active agent; describe it as a measured value coupled with a specific process.