# What symbol is used to represent enthalpy?

Mar 13, 2017

Chemists use the symbol $H$ to represent enthalpy.

#### Explanation:

In 1922, Alfred W. Porter proposed that $H$ become the accepted symbol for enthalpy.

The word enthalpy comes from the Greek en = "into" + thalpein = "to heat".

We cannot measure the total enthalpy, $H$, of a system directly.

Therefore, we measure the change in enthalpy, ΔH.

In symbols,

ΔH = ΔU + pΔV

where

ΔU" = thechange in internal energy;
$p$ = the external pressure, and
ΔV = the change in volume of the system.