Question

what is the molarity of a solution when 2.25 g naf is dissolved in enough water to make 25.0 ml of solution?

Answer 1

Molar mass Sodium Fluoride :

NaF = 22.98 + 18.99 => 41.97 g/mol

number of moles ( n ) :

mass of solute / molar mass

2.25 / 41.97 => 0.053 moles

Volume = 25.0 mL in liters : 25.0 / 1000 => 0.025 L 

M = n / V

M = 0.053 / 0.025

M = 2.12 mol/L

hope this helps!