/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 9 Is molality or molarity dependen... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 11: Problem 9

Is molality or molarity dependent on temperature? Explain your answer. Why is molality, and not molarity, used in the equations describing freezing-point depression and boiling-point elevation?

Short Answer

Expert verified
Molality is independent of temperature, as it depends on the mass of solvent, while molarity is dependent on temperature, as it depends on the volume of the solution which varies with temperature. Molality is used in equations describing freezing-point depression and boiling-point elevation because it provides an accurate ratio of solute-to-solvent particles that remains constant despite temperature changes, making it suitable for describing colligative properties.

Step by step solution

01

1. Define molality and molarity

Molality (m) is defined as the number of moles of solute (particle) per kilogram of solvent, with the equation: \(m = \frac{\text{moles of solute}}{\text{mass of solvent (kg)}}\). Molarity (M) is defined as the number of moles of solute per liter of solution, with the equation: \(M = \frac{\text{moles of solute}}{\text{volume of solution (L)}}\).
02

2. Molality and temperature

Since molality depends only on the mass of solvent, it remains constant with the changes in temperature, as mass does not change with temperature. Therefore, molality is independent of temperature.
03

3. Molarity and temperature

Molarity depends on the volume of the solution, which can change with temperature since the volume varies with temperature due to thermal expansion or contraction. Thus, molarity is dependent on temperature.
04

4. Focus on molality in colligative properties

Colligative properties are physical properties of solutions that depend on the ratio of solute particles' concentration to the solvent particles' concentration, such as freezing-point depression and boiling-point elevation. As molality is independent of temperature and gives an accurate ratio of solute to solvent particles, it is preferred over molarity in equations describing freezing-point depression and boiling-point elevation.
05

5. Conclusion

Molality is independent of temperature, while molarity is dependent on temperature. Molality is the preferred parameter for describing colligative properties like freezing-point depression and boiling-point elevation, as it offers a consistent measurement of solute-to-solvent concentration despite temperature changes.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

a. Use the following data to calculate the enthalpy of hydration for calcium chloride and calcium iodide. $$\begin{array}{lll}{\mathrm{CaCl}_{2}(s)} & {-2247 \mathrm{k} / \mathrm{mol}} & {-46 \mathrm{kJ} / \mathrm{mol}} \\ {\mathrm{Cal}_{2}(s)} & {-2059 \mathrm{k} / \mathrm{mol}} & {-104 \mathrm{kJ} / \mathrm{mol}}\end{array}$$ b. Based on your answers to part a, which ion, \(\mathrm{Cl}^{-}\) or \(\mathrm{I}^{-},\) is more strongly attracted to water?

If 500 . g of water is added to 75 \(\mathrm{g}\) of a \(2.5-m\) NaCl solution, what is the mass percent of \(\mathrm{NaCl}\) in the diluted solution?

A solution of phosphoric acid was made by dissolving 10.0 \(\mathrm{g}\) \(\mathrm{H}_{3} \mathrm{PO}_{4}\) in 100.0 \(\mathrm{mL}\) water. The resulting volume was 104 \(\mathrm{mL}\) . Calculate the density, mole fraction, molarity, and molality of the solution. Assume water has a density of 1.00 \(\mathrm{g} / \mathrm{cm}^{3}\) .

Erythrocytes are red blood cells containing hemoglobin. In a saline solution they shrivel when the salt concentration is high and swell when the salt concentration is low. In a \(25^{\circ} \mathrm{C}\) aqueous solution of NaCl, whose freezing point is \(-0.406^{\circ} \mathrm{C},\) erythrocytes neither swell nor shrink. If we want to calculate the osmotic pressure of the solution inside the erythrocytes under these conditions, what do we need to assume? Why? Estimate how good (or poor) of an assumption this is. Make this assumption and calculate the osmotic pressure of the solution inside the erythrocytes.

The term proof is defined as twice the percent by volume of pure ethanol in solution. Thus, a solution that is 95\(\%\) (by volume) ethanol is 190 proof. What is the molarity of ethanol in a 92 proof ethanol-water solution? Assume the density of ethanol, \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\) , is 0.79 \(\mathrm{g} / \mathrm{cm}^{3}\) and the density of water is 1.0 \(\mathrm{g} / \mathrm{cm}^{3}\) .
See all solutions

Recommended explanations on Chemistry Textbooks

Kinetics

Read Explanation

Making Measurements

Read Explanation

Chemical Analysis

Read Explanation

Physical Chemistry

Read Explanation

Chemistry Branches

Read Explanation

Ionic and Molecular Compounds

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.