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Ch.13 - Properties of Solutions
All textbooksBrown 15th EditionCh.13 - Properties of SolutionsProblem 4
Chapter 13, Problem 4

Which two statements about gas mixtures are true? [Section 13.1] (a) Gases always mix with other gases because the gas particles are too far apart to feel significant intermolecular attractions or repulsions. (b) Just like water and oil don’t mix in the liquid phase, two gases can be immiscible and not mix in the gas phase. (c) If you cool a gaseous mixture, you will liquefy all the gases at the same temperature. (d) Gases mix in all proportions in part because the entropy of the system increases upon doing so.

Verified step by step guidance
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Step 1: Understand the concept of gas mixtures. Gases tend to mix with each other due to their high kinetic energy and the large distances between particles, which minimize intermolecular forces.
Step 2: Evaluate statement (a). Consider the nature of gas particles and their interactions. Gases are generally able to mix because the particles are far apart, reducing the effect of intermolecular forces.
Step 3: Evaluate statement (b). Compare the behavior of gases to liquids like water and oil. Unlike liquids, gases do not have significant intermolecular forces that prevent mixing, so they are typically miscible.
Step 4: Evaluate statement (c). Consider the process of cooling a gas mixture. Different gases have different boiling points, so they do not liquefy at the same temperature.
Step 5: Evaluate statement (d). Consider the role of entropy in gas mixing. Mixing gases increases the disorder or entropy of the system, which is a driving force for mixing.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Gas Behavior and Mixing

Gases behave differently from liquids and solids due to the large distances between their particles. This spacing allows gas particles to move freely and mix uniformly with other gases. The lack of significant intermolecular forces in gases facilitates this mixing, leading to the conclusion that gases will always mix with one another under normal conditions.
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Entropy and Mixing

Entropy is a measure of the disorder or randomness in a system. When gases mix, the overall entropy of the system increases because the distribution of gas particles becomes more random. This increase in entropy is a driving force for the mixing of gases, as systems tend to evolve towards states of higher entropy.
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Gas Liquefaction

Liquefaction of gases occurs when they are cooled to their condensation points, which can vary for different gases. However, it is incorrect to assume that all gases in a mixture will liquefy at the same temperature, as each gas has its own unique boiling point. Therefore, cooling a gaseous mixture does not guarantee that all components will liquefy simultaneously.
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Related Practice
Textbook Question

This figure shows the interaction of a cation with surrounding water molecules. (b) Which of the following explanations accounts for the fact that the ion–solvent interaction is greater for Li+ than for K+? a. Li+ is of lower mass than K+. b. The ionization energy of Li is higher than that for K. c. Li+ has a smaller ionic radius than K+. d. Li has a lower density than K. e. Li reacts with water more slowly than K. [Section 13.1]

Textbook Question

Consider two ionic solids, both composed of singly charged ions, that have different lattice energies. (a) Will the solids have the same solubility in water? (b) If not, which solid will be more soluble in water, the one with the larger lattice energy or the one with the smaller lattice energy? Assume that solute–solvent interactions are the same for both solids. [Section 13.1]

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Textbook Question

The structures of vitamins E and B6 are shown below. Predict which is more water soluble and which is more fat soluble. [Section 13.3]