Question
Explain the standard state of an element.
✓
Answer
Standard state of an element: It is defined as the most stable state of an element at $298 K$ and 1 atmosphere (or 1 bar).
In this state, the enthalpy of the element is assumed to be zero.
$\therefore H ^0$ element or in general $H _{\text {element }}=0$
$\therefore H _{\text {graphite }}^0= H _{ H _2( g )}=0 ; H _{ Na (s)}=0 ; H _{ Hg (l)}=0$
In this state, the enthalpy of the element is assumed to be zero.
$\therefore H ^0$ element or in general $H _{\text {element }}=0$
$\therefore H _{\text {graphite }}^0= H _{ H _2( g )}=0 ; H _{ Na (s)}=0 ; H _{ Hg (l)}=0$
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