# A student mixes 0.79 grams of sodium carbonate into 50 mL of water. What is the molarity of the sodium carbonate solution?

Mar 19, 2018

$\text{0.15 M}$.

#### Explanation:

Molarity can be found with this formula:

$\text{molarity" = "number of moles"/"volume (L)}$

We know the volume, which is $\text{50 mL = 0.05 L}$.

We still need to know the number of moles, though, but we can find that from its mass.

$\text{0.79 g}$ of $N {a}_{2} C {O}_{3}$ is:

$\text{0.79 g"/"molar mass" = "0.79 g"/"105.99 g/mol" = "0.0075 mol}$

Now, we can just plug those values in to solve for molarity:

$\text{molarity" = "0.0075 mol"/"0.05 L" ="0.15 M}$