# How many grams do 3.3 x 10^2 atoms of calcium weigh?

Oct 1, 2016

Not a great deal.

#### Explanation:

$6.022 \times {10}^{23}$ $\text{calcium atoms}$ have a mass of $40.08 \cdot g$. The given large number is the $\text{Avogadro constant}$, of which you will have heard.

So, to work out the mass of 330 calcium atoms we calculate the quotient:

$\left(3.3 \times {10}^{2} {\text{ calcium atoms")/(6.022xx10^23" calcium atoms mol}}^{-} 1\right) \times 40.08 \cdot g \cdot m o {l}^{-} 1$

$=$ ??g.