Chp2_Various

# Chp2_Various - A 0.227-M solution of X(Mm = 195 g/mol has a...

This preview shows pages 1–2. Sign up to view the full content.

A 0.227-M solution of X (M m = 195 g/mol) has a density of 0.959 g/ml. What is the molality of X in the solution? Given Concentration Unit (GCU): 0.227 mol X / 1 L of soln Desired Concentration Unit (DCU): mol X / kg of solvent Note: we have mol X in both, so problem is effectively that of converting 1 L solution to mass of solvent. 1. Since GCU is expressed per L of solution, a convenient “size” sample is 1.0 L. Thus, 0.227 mol X. 2. The only information we have about the solution is the density, allowing us to convert volume of soln to mass soln. 1L * (0.959g/ml)*(1000mL/1L) = 959 g or 0.959 kg of solution. 3. mass of solution = 0.959 kg = mass of solvent + mass of solute . Since we need kg of solvent in the DCU, we must obtain mass of solute. 4. The only information given about the solute is the molar mass. As we have mol X, we convert: 0.227 mol X * (195 g/mol) * (1kg/1000g) = 0.0443kg solute. 5. Mass of solvent = 0.959 – 0.0443 = 0.915 kg. 6. Molality = 0.227 mol X/ 0.915 kg solvent = 0.248 m. Colligative Properties: P. Exp 2.14, p. 48. 62.3 g CaCl2 in 100 mL of water at 20ºC.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern