Question

an aqueous solution of licl is 34.0 % licl. what mass of water is present in 250.0 g of the solution? (density of water is 1.00 g/ml) (solution contains only licl and water.) a) 34.0 g b) 25.0 g c) 85.0 g d) 216.0 g e) 165.0 g

Explanation:

Step1: Find mass of LiCl

Mass of LiCl = 34.0% of 250.0 g = $0.340 \times 250.0$ g = 85.0 g

Step2: Calculate mass of water

Mass of solution = mass of LiCl + mass of water. So, mass of water = mass of solution - mass of LiCl = 250.0 g - 85.0 g = 165.0 g? Wait, no, wait: Wait, 34% LiCl means 66% water? Wait, 100 - 34 = 66. So mass of water = 66% of 250.0 g = $0.66 \times 250.0$ = 165.0? Wait, no, wait my first step: 34% of 250 is 85, so 250 - 85 = 165? Wait, but let's check again. Wait, the options have e) 165.0 g? Wait, no, wait 34% LiCl, so water is 66%? Wait 100 - 34 = 66. So 66% of 250 is 0.66*250 = 165. So that's correct. Wait, but let's do it step by step.

Wait, first, mass of LiCl: percentage by mass is (mass of solute / mass of solution) 100. So mass of LiCl = (34.0 / 100) 250.0 g = 85.0 g. Then, mass of water = mass of solution - mass of LiCl = 250.0 g - 85.0 g = 165.0 g. So that's the mass of water.

Answer:

e) 165.0 g