Question

The molar mass of NaOH is 40.00 g/mol. If 5.20 g NaOH are dissolved in 0.500 L of solution, what is the molarity of the solution?
0.0125 M
0.260 M
3.85 M
7.69 M

Answer 1

[ 5.20g / 0.5L ] x [1mole / 40.00g] = 0.260 M

Answer 2

 The molarity   of the solution is  0.260 M

 calculation

step 1: calculate  the moles of NaOH

moles  = mass÷ molar mas

= 5.20 g÷ 40.00 g/mol= 0.13  moles

Step 2: find the molarity of solution

molarity = moles÷volume  in liters

=0.13  moles÷ 0.500 L = 0.260 M