Question

Sucrose is very soluble in water. At 25◦C, 211.4 grams of sucrose will dissolve in 100 g of water. Given that the density of the saturated sucrose solution is 1.34 g/mL, what is the molarity of the solution? The molar mass of sucrose is 342 g/mol.

Answer 1

Molarity of solution = Number of moles of solute / Volume of solution (in liters)

Number of moles of solute = mass of solute / molar mass
                                           = 211.4 g / 342 g/mol  = 0.62 mol

Volume of solution = mass / density = 100 g / 1.34 g/ml = 74.6 ml = 74.6 * 10⁻³ Liter

Molarity = 0.62 / (74.6 * 10⁻³) = 8.3 M