I submitted this question yesterday; the first answer was right, the second was wrong. Please take another look. Thank you!  9.762 g of a non-volatile solute is dissolved in 175.0 g of water.The solute does not react with water nor dissociate in solution.Assume that the resulting solution displays ideal Raoult's law behaviour.At 25°C the vapour pressure of the solution is 23.405 torr.The vapour pressure of pure water at 25°C is 23.756 torr.Calculate the molar mass of the solute (g/mol). answer: 67.0 g/mol  -- correct  Now suppose, instead, that 9.762 g of a volatile solute is dissolved in 175.0 g of water.This solute also does not react with water nor dissociate in solution.The pure solute displays, at 25°C, a vapour pressure of 2.376 torr.Again, assume an ideal solution.If, at 25°C the vapour pressure of this solution is also 23.405 torr.Calculate the molar mass of this volatile solute. answer: 48.81 g/mol -- wrong  Hint: Note that the calculation is greatly simplified if you recognize that:  Xsolute= 1 - Xwater.Use this fact and the Raoult's Law expression for the total vapour pressure to solve for Xwater. Then express Xwater in terms of the relative masses, and solve for the molar mass of the solute. Actually, if you care to do the algebraic manipulations, a relatively simple expression can be derived for the molar mass in terms of the given masses and pressures.

Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
icon
Related questions
Question

I submitted this question yesterday; the first answer was right, the second was wrong. Please take another look. Thank you! 

  1. 9.762 g of a non-volatile solute is dissolved in 175.0 g of water.
    The solute does not react with water nor dissociate in solution.
    Assume that the resulting solution displays ideal Raoult's law behaviour.
    At 25°C the vapour pressure of the solution is 23.405 torr.
    The vapour pressure of pure water at 25°C is 23.756 torr.
    Calculate the molar mass of the solute (g/mol). answer: 67.0 g/mol  -- correct 

  2. Now suppose, instead, that 9.762 g of a volatile solute is dissolved in 175.0 g of water.
    This solute also does not react with water nor dissociate in solution.
    The pure solute displays, at 25°C, a vapour pressure of 2.376 torr.
    Again, assume an ideal solution.
    If, at 25°C the vapour pressure of this solution is also 23.405 torr.
    Calculate the molar mass of this volatile solute. answer: 48.81 g/mol -- wrong 

Hint:

Note that the calculation is greatly simplified if you recognize that:  Xsolute= 1 - Xwater.
Use this fact and the Raoult's Law expression for the total vapour pressure to solve for Xwater. Then express Xwater in terms of the relative masses, and solve for the molar mass of the solute. Actually, if you care to do the algebraic manipulations, a relatively simple expression can be derived for the molar mass in terms of the given masses and pressures.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 5 steps with 5 images

Blurred answer
Knowledge Booster
Solutions
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Chemistry
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry
Chemistry
Chemistry
ISBN:
9781259911156
Author:
Raymond Chang Dr., Jason Overby Professor
Publisher:
McGraw-Hill Education
Principles of Instrumental Analysis
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Organic Chemistry
Organic Chemistry
Chemistry
ISBN:
9780078021558
Author:
Janice Gorzynski Smith Dr.
Publisher:
McGraw-Hill Education
Chemistry: Principles and Reactions
Chemistry: Principles and Reactions
Chemistry
ISBN:
9781305079373
Author:
William L. Masterton, Cecile N. Hurley
Publisher:
Cengage Learning
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemistry
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY