Ch.11 - Liquids, Solids & Intermolecular ForcesWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: 1. Consider the following two substances and their vapor pressures at 298 K.Substance Vapor Pressure (mmHg)A 275B 459Based on this information compare the characteristcs of the two substances.weaker i

Problem

1. Consider the following two substances and their vapor pressures at 298 K.

Substance Vapor Pressure (mmHg)

A 275

B 459

Based on this information compare the characteristcs of the two substances.

weaker intermolecular force

higher boiling point

higher heat of vaporization

exist in gaseous phase at 300 K

2. The vapor pressure of dichloromethane, CH 2Cl2, at 0°C is 134 mmHg. The normal boiling point of dichloromethane is 40. Calculate its molar heat of vaporization?

Solution

1. Substance A has a lower vapor pressure than substance B. A lower vapor pressure means stronger intermolecular forces because the liquid molecules do not easily escape to the gaseous phase. Therefore, substance A has a stronger intermolecular force and substance B has a weaker intermolecular force.


Since Substance A has a stronger intermolecular force, it also has a higher boiling point and higher heat of vaporization. This is because more energy (in the form of heat) is needed to bring the liquid to boil and to vaporize the liquid


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