Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 12: Problem 24

The density of an aqueous solution containing \(10 . \overline{0}\) percent of ethanol \(\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)\) by mass is \(0.984 \mathrm{~g} / \mathrm{mL} .\) (a) Calculate the molality of this solution. (b) Calculate its molarity. (c) What volume of the solution would contain 0.125 mole of ethanol?

Short Answer

Expert verified
The molality of the solution is 2.41 mol/kg, the molarity of the solution is 2.14 M and the volume of the solution that would contain 0.125 mole of ethanol is 58.4 mL.

Step by step solution

01

Calculate molality

The formula for molality (m) is m = moles of solute / kilograms of solvent. Here the mass percentage of ethanol is 10.0, that means in 100g solution ethanol is 10g. In order to find moles, use the molar mass of ethanol which is approximately 46.07 g/mol. Hence, the moles of ethanol will be 10g / 46.07 g/mol = 0.217 moles. Now, subtract the mass of ethanol from the total solution to get the mass of water (solvent). The mass of water would be 100g - 10g = 90g or 0.09kg. Therefore, molality would be 0.217 moles / 0.09 kg = 2.41 mol/kg.
02

Calculate molarity

The formula for molarity (M) is M = moles of solute / volume of solution in liters. We know the moles of ethanol is 0.217 (calculated in step 1). We know that the density of the solution is 0.984 g/ml. Since there are 100g of the solution, it means that the volume of the solution is 100g / 0.984 g/mL = 101.6 mL or 0.1016 L. Therefore, molarity would be 0.217 moles / 0.1016 L = 2.14 M.
03

Calculate volume of the solution containing 0.125 mole of ethanol

We can use the molarity calculated in the Step 2 to find this volume. The formula that relates moles (n), molarity (M) and volume (V) is n = M*V. So, rearrange this equation to solve for volume, V = n / M = 0.125 moles / 2.14 M = 0.0584 L or 58.4 mL.

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.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

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

Both \(\mathrm{NaCl}\) and \(\mathrm{CaCl}_{2}\) are used to melt ice on roads and sidewalks in winter. What advantages do these substances have over sucrose or urea in lowering the freezing point of water?

A student carried out the following procedure to measure the pressure of carbon dioxide in a soft drink bottle. First, she weighed the bottle \((853.5 \mathrm{~g})\). Next, she carefully removed the cap to let the \(\mathrm{CO}_{2}\) gas escape. She then reweighed the bottle with the cap \((851.3 \mathrm{~g})\). Finally, she measured the volume of the soft drink ( \(452.4 \mathrm{~mL}\) ). Given that Henry's law constant for \(\mathrm{CO}_{2}\) in water at \(25^{\circ} \mathrm{C}\) is \(3.4 \times 10^{-2}\) \(\mathrm{mol} / \mathrm{L} \cdot \mathrm{atm},\) calculate the pressure of \(\mathrm{CO}_{2}\) in the original bottle. Why is this pressure only an estimate of the true value?

What are ion pairs? What effect does ion-pair formation have on the colligative properties of a solution? How does the ease of ion-pair formation depend on (a) charges on the ions, (b) size of the ions, (c) nature of the solvent (polar versus nonpolar), (d) concentration?

Calculate the molarity and the molality of an \(\mathrm{NH}_{3}\) solution made up of \(30.0 \mathrm{~g}\) of \(\mathrm{NH}_{3}\) in \(70.0 \mathrm{~g}\) of water. The density of the solution is \(0.982 \mathrm{~g} / \mathrm{mL}\).

The concentration of commercially available concentrated sulfuric acid is 98.0 percent by mass, or \(18 M\). Calculate the density and the molality of the solution.
See all solutions

Recommended explanations on Chemistry Textbooks

The Earths Atmosphere

Read Explanation

Making Measurements

Read Explanation

Physical Chemistry

Read Explanation

Nuclear Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Organic Chemistry

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.

Sign-up for free