If an aqueous solution contains 70% of Isopropyl Alcohol (d = 0.786 g/ml):

a: how many ml are alcohol?

b: how many ml are water?

c: how many grams of alcohol were used to prepare this solution?

A. 70mL.

B. 30mL.

C. 55.02g.

Explanation:

Data obtained from the question include:

Percentage of Isopropyl Alcohol = 70%

Density of Isopropyl Alcohol = 0.786g/mL

Percentage of the solution = 100%

A. Determination of the volume of the alcohol.

Percentage volume of solute =

volume of solute / Volume of solution x

100

70% = volume of solute/100

70/100 = volume of solute / 100

Cross multiply

Volume of solute = 70/100 x 100

Volume of solute = 70mL.

Therefore, the volume of the alcohol is 70mL.

B. Determination of the volume of water.

Volume of solute (alcohol) = 70mL

Volume of solution = 100mL

Volume of water = ... ?

Volume of solution = volume solute + volume of water

100 = 70 + volume of water

Collect like terms

Volume of water = 100 - 70 = 30mL

Therefore, the volume of water is 30mL

C. Determination of the mass of alcohol in the solution

Density of Isopropyl Alcohol = 0.786g/mL

Volume of Isopropyl Alcohol = 70mL

Mass of Isopropyl Alcohol =.?

Density = Mass / volume

0.786 = Mass / 70

Cross multiply

Mass = 0.786 x 70

Mass = 55.02g

Therefore, the mass of the alcohol used in preparing the solution is 55.02g.