Answer to Question #306914 in General Chemistry for Ernest Rendon

Question

A solution is prepared by dissolving 10.00 g sucrose (MM of sucrose = 343 g) in 50g of water. The volume of the resulting solution is 52 mL. Calculate the following

A. molarity

B. molality

C. mole fraction

Answer 1

n_sucrose = 10/343 = 0.0291 mol

n_water = 50/18 = 2.78 mol

Molarity or molar concentration is the number of moles of solute per liter of solution:

c_sucrose = n_solute/V_solution =1000*0.0291/52 = 0.56 mol/l

Molality is the number of moles of solute per kilogram of solvent:

b_sucrose = n_solute/m_solution = 1000*0.0291/50 = 0.582 mol/kg

Mole fraction is the number of molecules (or moles) of one component divided by total the number of molecules (or moles) in the mixture:

x_sucrose = 0.0291/(0.0291+2.78) = 0.0104