Answer
The molarity of this solution is equal to 0.500 M $NaOH$
Work Step by Step
- Calculate or find the molar mass for $ NaOH $:
$ NaOH $ : ( 22.99 $\times$ 1 )+ ( 1.008 $\times$ 1 )+ ( 16.00 $\times$ 1 )= 40.00 g/mol
- Using the molar mass as a conversion factor, find the amount in moles:
$$ 8.0 \space g \times \frac{1 \space mole}{ 40.00 \space g} = 0.200 \space mole$$
$1 \space L = 1000 \space mL$
$$Volume(L) = 400. \space mL \times \frac{1 \space L}{1000 \space mL} = 0.400 \space L$$
- Write the molarity expression and evaluate it:
$$Molarity(M) = \frac{moles \space of \space solute}{liters \space of \space solution}$$
$$= \frac{0.200 \space mole \space NaOH}{ 0.400 \space L \space solution} = 0.500 \space M \space NaOH \space solution$$
