molarity is defined as the number of moles in 1 L of solution
number of moles of sodium acetate is - 8.56 g / 82.03 g/mol = 0.104 mol
number of acetate moles in 750.0 mL - 0.104 mol
then number of acetate moles in 1000 mL - 0.104 mol / 0.7500 L = 0.139 mol/L
molarity of sodium acetate is 0.139 M