Question

What is the concentration of a solution created by mixing 25g of C₃H₆O_(L) (D = 0.774 g/mL) with 25g of CH₄O_(L) (D = 0.890 g/mL)?

Answer 1

Given data:

The following values are given in the question.

Mass of C3H6O = 25g; Density =  0.774 g/mL

Mass of CH4O = 25g; Density =  0.890 g/mL

Key points:

1. A solution is composed in majority of a solvent. That is more of solvent then the solute.

Solution:

Step 1: Calculate the volume

Volume of C3H6O = m / D; where m is mass = 25g and D is density = 0.774 g/mL

Volume of C3H6O = 25g / (0.774 g/mL) =  32.2997mL = 32.3mL

Volume of CH4O = 25g / (0.890 g/mL) =  28.0899mL = 28.1mL

In the created solution, volume of CH4O, 28.1mL is less than the volume of C3H6O, 32.3mL. Hence CH4O is the solute and C3H6O is the solvent.

Volume of solution = Volume of CH4O + Volume of C3H6O = 28.1mL + 32.3mL = 60.4mL

Hence the volume of solution is 60.4mL.

Step 2: Calculate the concentration

Concentration = (Volume of solute / Volume of solution) x 100

Substitute the values;

Concentration = (28.1mL / 60.4mL) x 100 = 0.465 x 100 = 46.5%

Hence the concentration of CH4O in the created solution is 46.5% v/v.