Question

What mass of $NaOH$is contained in 250.0 mL of a 0.400 M sodium hydroxide solution?

Short answer

The mass of$NaOH$is contained in 250.0 mL of a 0.400 M sodium hydroxide solution is $4.0g$.

Step-by-step solution

Definition

The molar mass of a material is defined as the mass of the substance contained in one mole of the substance, and it isequal to the total mass of the component atoms. It may be stated mathematically as follows:

$Molarmass\mathit{}=\frac{Weighting}{numberofmoles}$

Determination of mass of NaOH

Moles of $NaOH=\left(Molarity\right)\left(volumeinL\right)$

$$\begin{gathered} =\left(0.400M\right)\left(0.250L\right) \\ =0.1\text{Moles} \end{gathered}$$

Molar Mass of $NaOH=23+16+1$

$=40\raisebox{1ex}{$g$}\!\left/ \!\raisebox{-1ex}{$mol$}\right.$

Mass of $NaOH$in 250.0mL of 0.400M$NaOH=\left(Moles\right)\left(Molarmass\right)$

$=\left(0.1mol\right)\left(40\frac{g}{mol}\right)$

$=4.0g$

Therefore The Massof $NaOH$is$4.0g$.