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Ch.11 - Liquids and Intermolecular Forces
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
All textbooksBrown 14th EditionCh.11 - Liquids and Intermolecular ForcesProblem 12
Chapter 11, Problem 12

At room temperature, Si is a solid, CCl4 is a liquid, and Ar is a gas. List these substances in order of (b) increasing boiling point.

Verified step by step guidance
1
Identify the type of intermolecular forces present in each substance: Si (silicon) is a network covalent solid, CCl4 (carbon tetrachloride) is a molecular compound with London dispersion forces, and Ar (argon) is a noble gas with weak London dispersion forces.
Understand that the strength of intermolecular forces affects the boiling point: stronger intermolecular forces result in higher boiling points.
Recognize that network covalent solids like Si have very strong covalent bonds throughout the structure, leading to high boiling points.
Compare the intermolecular forces: Si has the strongest forces due to its covalent network, CCl4 has moderate London dispersion forces, and Ar has the weakest London dispersion forces.
Arrange the substances in order of increasing boiling point based on the strength of their intermolecular forces: Ar < CCl4 < Si.

Key Concepts

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

Boiling Point

The boiling point of a substance is the temperature at which its vapor pressure equals the external pressure, causing it to change from a liquid to a gas. It is influenced by intermolecular forces; stronger forces typically result in higher boiling points. For example, substances with hydrogen bonding or significant dipole-dipole interactions generally have higher boiling points than those with only London dispersion forces.
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Intermolecular Forces

Intermolecular forces are the forces of attraction or repulsion between molecules. They include hydrogen bonds, dipole-dipole interactions, and London dispersion forces. The strength of these forces affects the physical properties of substances, including boiling points; for instance, carbon tetrachloride (CCl4) has stronger dispersion forces than argon (Ar), leading to a higher boiling point.
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Phase of Matter

The phase of matter refers to the distinct forms that different phases of matter take on, primarily solid, liquid, and gas. At room temperature, silicon (Si) is a solid due to its strong covalent bonds, CCl4 is a liquid with moderate intermolecular forces, and argon (Ar) is a gas with weak dispersion forces. Understanding these phases helps in predicting the order of boiling points based on the state of matter at a given temperature.
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Related Practice
Textbook Question

At standard temperature and pressure, the molar volumes of Cl2 and NH3 gases are 22.06 and 22.40 L, respectively. (c) The densities of crystalline Cl2 and NH3 at 160 K are 2.02 and 0.84 g/cm3, respectively. Calculate their molar volumes.

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Textbook Question

At standard temperature and pressure, the molar volumes of Cl2 and NH3 gases are 22.06 and 22.40 L, respectively (d) Are the molar volumes in the solid state as similar as they are in the gaseous state? Explain.

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Textbook Question

(a) Which type of intermolecular attractive force operates between all molecules?

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Textbook Question

(c) What happens to a gas if you put it under extremely high pressure?

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Textbook Question

(a) How does the average kinetic energy of molecules com- pare with the average energy of attraction between mole- cules in solids, liquids, and gases?

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