Question

Calculate the average atomic mass of hydrogen using the following data

$\begin{array}{ccc}Isotope& \%Naturalabudance& Molarmass\\ {}^{1}H& 99.985& 1\\ {}^{2}H& 0.015& 2\end{array}$

Answer 1

Many naturally occuring elements exist as more than one isotope. When we take into account the existence of these isotopes and their relative abudance (per cent occurrence) the average atomic mass of the element can be calculated as

$\left\{\right(Naturalabudanceof{}^{1}H\times molarmass)+$
$Averageatomicmass=\frac{(Naturalabundanceof{}^{2}H\times molarmasso{f}^{2}H)\}}{100}$
$=\frac{99.985\times 1+0.015\times 2}{100}$
$=\frac{99.985+0.030}{100}=\frac{100.015}{100}=1.00015u$