Calculate the grams of solute needed to prepare a 2.0 L solution of 6.0 M NaOH?

Question

Calculate the grams of solute needed to prepare a 2.0 L solution of 6.0 M NaOH?

Answer 1

Moles NaOH = 2.0 L x 6.0 M = 12.0

Mass NaOH = 12.0 mol x 40 g/mol = 480 g

Answer 2

Given:

Molar Mass of NaOH = 40.00g/mol

Volume of solution (in liters) = 2.0L

Molarity of solution = 6.0M

Molarity = moles of solute / volume of solution in liters

Since moles of solute = mass of solute / molar mass of solute; then

Molarity = (mass of solute / molar mass of solute) / liters of solution

Rearranging the equation to solve for the mass of solute, we get

mass of solute = Molarity x volume of solution in liters x molar mass of solute

mass of solute = 6.0mol/L x 2.0L x 40.00g/mol

mass of solute = 480grams

Answer: 480 grams