Chemistry

Catherine E. Housecroft, Edwin C. Constable

ISBN #9780273715450

4th Edition

995 Questions

13,222 Students Helped

Homework Questions

Summary

Learning Objectives

Key Concepts

Example Problems

Explanations

Common Mistakes

Summary

This section provides an overview of key thermodynamic concepts, emphasizing the role of internal energy and its measurement via the bomb calorimeter. By studying heat capacities, students learn how materials respond to temperature changes under different conditions. The integration of theoretical principles with practical applications builds a strong foundation for further study in energy systems and engineering design.

Learning Objectives

Key Concepts

CONCEPT

DEFINITION

Acyclic and cyclic alkanes

A discussion of both open?chain (acyclic) and ring (cyclic) saturated hydrocarbons, emphasizing their structural features, nomenclature, conformational behavior (including ring strain and conformation), and the processes used in their interconversion and synthesis.

Example Problems

Example 1

In equation $17.9,$ show that units of Pa for pressure and $m^{3}$ for volume are compatible with J for $\Delta H$ [Hint: refer to Table $1.2 .]$

Example 2

(a) Calculate the work done on the surroundings at 1 bar pressure and $298 \mathrm{K}$ when 0.200 mole $\mathrm{H}_{2} \mathrm{O}_{2}$ decomposes (volume occupied by 1 mole of gas at 1 bar and $273 \mathrm{K}=22.7 \mathrm{dm}^{3}$ ). (b) If the standard enthalpy of reaction is $-98.2 \mathrm{kJ}$ per mole of $\mathrm{H}_{2} \mathrm{O}_{2}$ what is the corresponding change in the internal energy of the system?

Example 3

In equation $17.13,$ for 1 mole of pentane, $\Delta n=-3 .$ What would happen if the reaction were defined so as to produce water in the gas phase?

Example 4

How does the molar heat capacity of a substance differ from the specific heat capacity?

Example 5

Estimate the enthalpy change at $400 \mathrm{K}$ that accompanies the reaction: $\mathrm{Li}(\mathrm{s})+\frac{1}{2} \mathrm{Cl}_{2}(\mathrm{g})-\mathrm{LiCl}(\mathrm{s})$ if $\Delta_{f} H^{\circ}(298 \mathrm{K}) \mathrm{LiCl}(\mathrm{s})=-408.6 \mathrm{kJ} \mathrm{mol}^{-1},$ and values of $C_{p}(298 \mathrm{K})$ are $\mathrm{Li} 24.8, \mathrm{Cl}_{2} 33.9$ and LiCl $48.0 \mathrm{JK}^{-1} \mathrm{mol}^{-1}$.