Answer to Question #162552 in General Chemistry for Sage Topaz

Question

A solution is made by dissolving 1.25 g of C2H5OH in 11.6 g of H2O. Calculate the mass percent of C2H5OH, the mass percent of H2O, molality of C2H5OH.

Answer 1

Mass of C₂H₅OH = 1.25 g

Mass of H₂O = 11.6 g

Mass percent of C₂H₅ OH

= 1.25 × 100 / 1.25 + 11.6

= 125 / 12.86

= 9.72 .

Mass percent of H₂O = 100 - 9.72 = 90.28 %.

Molality

= moles of ethyl Alcohol/mass of solvent in kg

= 1.25 / 46 / 11.6 / 1000

= 1.25 × 1000 / 11.6 × 46

= 2.342578 mol / kg .