# What mass of solute is present in 250. mL of a 0.100 mol/L solution of NaOH (molar mass of NaOH = 40.000 g/mol)?

Sep 11, 2017

$100 \cdot m g$.........

#### Explanation:

As with all these problems, we use the relationship.....

$\text{Concentration"-="Amount of solute"/"Volume of solution}$

And typically we report the molarity, where.....

$\text{Molarity"="Moles of solute (mol)"/"Volume of solution (L)}$

And thus the units of $\text{molarity}$ are $m o l \cdot {L}^{-} 1$.

And so....$\text{moles of solute"="Molarity"xx"Volume}$

$= 0.100 \cdot m o l \cdot \cancel{{L}^{-} 1} \times 250 \cdot \cancel{m L} \times {10}^{-} 3 \cdot \cancel{L \cdot m {L}^{-} 1}$...

$= 2.50 \times {10}^{-} 3 \cdot m o l$

And this represents a mass of................

2.50xx10^-3*molxx40.00*g*mol^-1=??*g