How many grams of NaOH are
needed to make 400. mL of
1.50 M solution?

24g of NaOH are required

Explanation:

Molarity, M, is an unit of concentration widely used in chemistry defined as the ratio between moles of solute (In this case, NaOH), and volume of solution in liters.

We can find the moles of NaOH and its mass with the volume and desired concentration as follows:

Moles NaOH:

400.0mL = 0.400L * (1.50mol / L) = 0.600 moles NaOH

Mass NaOH -Molar mass: 40.0g/mol-:

0.600 moles * (40.0g / mol) =