Question

16. How many liters of a 2.5% solution of sucrose would contain the same number of grams of sugar as 3.75 L of a 6.0% sucrose solution?

17. A hydrated compound has an analysis of 18.29% Ca, 32.37% Cl and 49.34% H2O. What is its formula?

18. Antibiotics are complex organic chemicals which have the ability to destroy or inhibit the growth of microorganisms such as bacteria and viruses. Aureomycin is an antibiotic which contains 55.2% C, 26.7% O, 5.85% N, 7.40% Cl and 4.84% H. What is the molecular formula of aureomycin which has a molecular mas of 479?

Answer 1

16.)

mass % of sucrose = 2.5 % (M1)

mass % of sucrose = 6.0 % (M2)

volume of sucrose = 3.75 L (V2)

M1 V1 = M2 V2

2.5 x V1 = 6.0 x 3.75

V1 = 9.00 L

volume of sucrose solution = 9.00 L

17)

18.29% Ca, 32.37% Cl and 49.34% H2O

moles of Ca = 18.29 / 40 = 0.457

moles of Cl = 32.27 / 35.5 = 0.913

moles of H2O = 49.34 / 18.02 = 2.74

ratios :

        Ca           Cl            H2O

    0.457         0.913       2.74

        1               2            6

formula of hydrate = CaCl2.6H2O