A 1.5 M solution of NaOH was made in a laboratory. If the solution made had a volume of 4.5 L, how many grams of NaOH were added?

270g

Explanation:

Given parameters:

Concentration of solution = 1.5M

Volume of solution  = 4.5L

Unknown:

Mass of NaOH added  = ?

Solution:

Concentration is the number of moles of solute found in a solution.

 To solve this problem, we need to find the number of moles of NaOH first;

 Number of moles  = concentration x volume

 Number of moles  = 1.5 x 4.5  = 6.75moles

 Now, to find the mass of NaOH;

  Mass of NaOH = number of moles x molar mass

       Molar mass of NaOH  = 23 + 16 + 1  = 40g

 Mass of NaOH  = 6.75 x 40  = 270g