Question

Convert 18 amu to mole. [Explanation is required]

Answer 1

$\large\underline{\rm Atomic \: mass \: unit \; (amu)-}$

The quantity of ${\sf 1/12 ^{th} }$ mass of an atom of C¹² is known as atomic mass unit

Since mass of 1 atom of C - 12 = ${\sf 1.9924×10^{-23}g}$

⛬${\sf 1/12 \: ^{th}}$ part of the mass of 1 atom

$\implies{\sf \dfrac{1.9924×10^{-24}}{12}\:\implies\:1.67×10^{-24}g\:\implies\:1\:amu=\dfrac{1}{6.023×10^{23}}}$

$\color{red}\implies{\sf 1\:amu=1.67×10^{-24}g}$

━━━━━━━━━━━━━━━━━━━━━━━━━━

Here we have to Convert 18 amu to mole.

$\implies{\sf 1\;amu=1.67×10^{-24} }$

$\implies{\sf \therefore \: \: 18\:amu=18×1.67×10^{-24}}$

$\implies{\sf 18\:amu=30.06×10^{-24}\:g}$

We know that

$\color{violet}\bullet\underline{\boxed{\sf Mole=\dfrac{Mass}{Molecular\:Mass(M_w)}}}$

$\color{red}\implies{\sf Mole(n)=\dfrac{30.06×10^{-24}}{M_w} }$

$\color{darkblue}\underline{\underline{\sf Answer-}}$

18 amu to mole is $\color{red}{\sf \dfrac{30.06×10^{-24}}{M_w}}$.