# Question e4dde

Jun 19, 2017

$1.56 \times {10}^{21}$ $\text{atoms Na}$

$= 0.00259$ $\text{mol Na}$

$= 0.0596$ $\text{g Na}$

#### Explanation:

Your answer is in the question: $1.56 \times {10}^{21}$ atoms of $\text{Na}$ is equal to $1.56 \times {10}^{21}$ atoms of $\text{Na}$.

If you would like to find the number of moles present, you can use Avogadro's number to find this:

1.56 xx 10^21 cancel("atoms Na")((1color(white)(l)"mol Na")/(6.022 xx 10^23cancel("atoms Na")))
= color(red)(0.00259 color(red)("mol Na"

You can also find the mass of sodium present, using the molar mass of sodium, $22.99 \text{g"/"mol}$ (found on a periodic table):

color(red)(0.00259 cancel(color(red)("mol Na"))((22.99color(white)(l)"g Na")/(1cancel("mol Na"))) = color(blue)(0.0596 color(blue)("g Na"#