Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 9: Problem 70

A liquid has a vapor pressure of \(159 \mathrm{~mm} \mathrm{Hg}\) at \(20^{\circ} \mathrm{C}\) and \(165 \mathrm{~mm} \mathrm{Hg}\) at \(30^{\circ} \mathrm{C}\). Different amounts of the liquid are added to three identical evacuated steel tanks kept at \(20^{\circ} \mathrm{C}\). The tanks are all fitted with pressure gauges. For each part, write \(\mathbf{L} / \mathbf{G}\) if both liquid and gas are present. G if only gas is present. I if the situation is impossible. (a) The pressure gauge in Flask I registers a pressure of \(256 \mathrm{~mm} \mathrm{Hg}\). (b) The pressure gauge in Flask II registers a pressure of \(135 \mathrm{~mm} \mathrm{Hg}\). (c) The pressure gauge in Flask III registers a pressure of \(165 \mathrm{~mm} \mathrm{Hg}\) at \(30^{\circ} \mathrm{C}\). The temperature is lowered to \(20^{\circ} \mathrm{C}\), and the gauge registers a pressure of \(159 \mathrm{~mm} \mathrm{Hg}\).

Short Answer

Expert verified
Answer: In Flask I, both liquid and gas (L/G) are present. In Flask II, only gas (G) is present. In Flask III, both liquid and gas (L/G) are present.

Step by step solution

01

Recall the concept of vapor pressure

Vapor pressure is the pressure exerted by the vapor in equilibrium with its liquid (or solid) phase at a given temperature. The higher the temperature, the higher the vapor pressure (usually). In this exercise, the vapor pressure of the liquid is given at two temperatures, 20°C and 30°C.
02

Analyze Flask I

In Flask I, the pressure gauge registers a pressure of 256 mm Hg at 20°C. Recall that the vapor pressure at 20°C is 159 mm Hg. Since the measured pressure (256 mm Hg) is greater than the vapor pressure (159 mm Hg), there must be both liquid and gas present in the flask. Therefore, the answer for Flask I is L/G.
03

Analyze Flask II

In Flask II, the pressure gauge registers a pressure of 135 mm Hg at 20°C. Recall that the vapor pressure at 20°C is 159 mm Hg. Since the measured pressure (135 mm Hg) is lower than the vapor pressure (159 mm Hg), only gas is present in the flask. Hence, the answer for Flask II is G.
04

Analyze Flask III

In Flask III, the pressure gauge registers a pressure of 165 mm Hg at 30°C. Recall that the vapor pressure at 30°C is 165 mm Hg. The pressure gauge measures the same pressure as the vapor pressure as the temperature is lowered to 20°C, the gauge registers a pressure of 159 mm Hg, which is the vapor pressure at 20°C. Since the measured pressure is equal to the vapor pressure at both temperatures, there must be both liquid and gas present in equilibrium with each other in the flask. Consequently, the answer for Flask III is L/G.

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

Of the four general types of solids, which one(s) (a) are generally low-boiling? (b) are ductile and malleable? (c) are generally soluble in nonpolar solvents?

In the blanks provided, answer the questions below, using LT (for is less than), GT (for is greater than), \(\mathrm{EQ}\) (for is equal to), or MI (for more information required). (a) The boiling point of \(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}(\mathrm{MM}=60.0 \mathrm{~g} / \mathrm{mol})\) the boiling point of \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{C}=\mathrm{O}(\mathrm{MM}=58.0 \mathrm{~g} / \mathrm{mol})\). (b) The vapor pressure of \(\mathrm{X}\) is \(250 \mathrm{~mm} \mathrm{Hg}\) at \(57^{\circ} \mathrm{C}\). Given a sealed flask at \(57^{\circ} \mathrm{C}\) that contains only gas, the pressure in the flask \(245 \mathrm{~mm} \mathrm{Hg}\) (c) The melting-point curve for Y tilts to the right of a straight line. The density of \(\mathrm{Y}(l) \quad\) the density of \(\mathrm{Y}(s)\). (d) The normal boiling point of \(\mathrm{A}\) is \(85^{\circ} \mathrm{C}\), while the normal boiling point of \(\mathrm{B}\) is \(45^{\circ} \mathrm{C}\). The vapor pressure of \(\mathrm{A}\) at \(85^{\circ} \mathrm{C}\) pressure of \(\mathrm{B}\) at \(45^{\circ} \mathrm{C}\). (e) The triple point of \(A\) is \(25 \mathrm{~mm} \mathrm{Hg}\) and \(5^{\circ} \mathrm{C}\). The melting point of \(\mathrm{A}\) \(5^{\circ} \mathrm{C}\)

Describe the structural units in (a) C (graphite) (b) \(\mathrm{SiC}\) (c) \(\mathrm{FeCl}_{2}\) (d) \(\mathrm{C}_{2} \mathrm{H}_{2}\)

Iodine has a triple point at \(114^{\circ} \mathrm{C}, 90 \mathrm{~mm} \mathrm{Hg}\). Its critical temperature is \(535^{\circ} \mathrm{C}\). The density of the solid is \(4.93 \mathrm{~g} / \mathrm{cm}^{3}\), and that of the liquid is \(4.00 \mathrm{~g} / \mathrm{cm}^{3}\). Sketch the phase diagram for iodine and use it to fill in the blanks using either "liquid" or "solid." (a) Iodine vapor at \(80 \mathrm{~mm} \mathrm{Hg}\) condenses to the when cooled sufficiently. (b) Iodine vapor at \(125^{\circ} \mathrm{C}\) condenses to the pressure is applied. (c) Iodine vapor at \(700 \mathrm{~mm} \mathrm{Hg}\) condenses to the when cooled above the triple point temperature.

For each of the following pairs, choose the member with the lower boiling point. Explain your reason in each case. (a) \(\mathrm{NaCl}\) or \(\mathrm{PCl}_{3}\) (b) \(\mathrm{NH}_{3}\) or \(\mathrm{AsH}_{3}\) (c) \(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}\) or \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OCH}_{3}\) (d) \(\mathrm{HI}(g)\) or \(\mathrm{HCl}(g)\)
See all solutions

Recommended explanations on Chemistry Textbooks

Organic Chemistry

Read Explanation

Nuclear Chemistry

Read Explanation

Chemistry Branches

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Kinetics

Read Explanation

Chemical Reactions

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