Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 5: Problem 83

Use bond enthalpies in Table 5.4 to estimate \(\Delta H\) for each of the following reactions: (a) $\mathrm{H}-\mathrm{H}(g)+\mathrm{Br}-\mathrm{Br}(g) \longrightarrow 2 \mathrm{H}-\mathrm{Br}(g)$ (b)

Short Answer

Expert verified
To estimate the change in enthalpy, ΔH, for reaction (a), first identify the bonds formed and broken during the reaction: - Breaking: 1 H-H bond and 1 Br-Br bond - Forming: 2 H-Br bonds Next, use the bond enthalpy values from Table 5.4: - H-H bond: 436 kJ/mol - Br-Br bond: 193 kJ/mol - H-Br bond: 364 kJ/mol The equation for ΔH is: ΔH = (Bond enthalpies of bonds broken) - (Bond enthalpies of bonds formed) ΔH = [(1 × 436) + (1 × 193)] - (2 × 364) = 629 - 728 = -99 kJ/mol So, for reaction (a), ΔH = -99 kJ/mol.

Step by step solution

01

Identify the bonds formed and broken in the first reaction

In reaction (a), we have: - Breaking: 1 H-H bond and 1 Br-Br bond - Forming: 2 H-Br bonds
02

Write the equation for ΔH in terms of bond enthalpies

Using the bond enthalpies, we can write the equation for ΔH as: ΔH = (Bond enthalpies of bonds broken) - (Bond enthalpies of bonds formed)
03

Find the bond enthalpy values from Table 5.4

Look up the bond enthalpy values for the bonds involved in the reaction from Table 5.4: - H-H bond: 436 kJ/mol - Br-Br bond: 193 kJ/mol - H-Br bond: 364 kJ/mol
04

Calculate ΔH for the first reaction

Use the bond enthalpy values found in Table 5.4 to substitute into the ΔH equation: ΔH = [(1 × 436) + (1 × 193)] - (2 × 364) = 629 - 728 = -99 kJ/mol For reaction (a), ΔH = -99 kJ/mol
05

Identify the bonds formed and broken in the second reaction

In reaction (b), repeat steps 1 through 4, taking care to use the bond information given for the specific reaction.

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

At the end of 2012, global population was about 7.0 billion people. What mass of glucose in kg would be needed to provide 1500 Cal/person/day of nourishment to the global population for one year? Assume that glucose is metabolized entirely to \(\mathrm{CO}_{2}(g)\) and \(\mathrm{H}_{2} \mathrm{O}(l)\) according to the following thermochemical equation: $$ \begin{aligned} \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(s)+6 \mathrm{O}_{2}(g) \longrightarrow 6 \mathrm{CO}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(l) \\ \Delta H^{\circ} &=-2803 \mathrm{~kJ} \end{aligned} $$

A sodium ion, \(\mathrm{Na}^{+}\), with a charge of $1.6 \times 10^{-19} \mathrm{C}\( and a chloride ion, \)\mathrm{Cl}^{-}\(, with charge of \)-1.6 \times 10^{-19} \mathrm{C}\(, are separated by a distance of \)0.50 \mathrm{nm}$. How much work would be required to increase the separation of the two ions to an infinite distance?

Imagine that you are climbing a mountain. (a) Is the distance you travel to the top a state function? (b) Is the change in elevation between your base camp and the peak a state function? [Section 5.2\(]\)

(a) According to the first law of thermodynamics, what quantity is conserved? (b) What is meant by the internal energy of a system? (c) By what means can the internal energy of a closed system increase?

For the following processes, calculate the change in internal energy of the system and determine whether the process is endothermic or exothermic: (a) A balloon is cooled by removing \(0.655 \mathrm{~kJ}\) of heat. It shrinks on cooling, and the atmosphere does \(382 \mathrm{~J}\) of work on the balloon. (b) A 100.0-g bar of gold is heated from \(25^{\circ} \mathrm{C}\) to \(50^{\circ} \mathrm{C}\) during which it absorbs \(322 \mathrm{~J}\) of heat. Assume the volume of the gold bar remains constant.
See all solutions

Recommended explanations on Chemistry Textbooks

Ionic and Molecular Compounds

Read Explanation

Inorganic Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Organic Chemistry

Read Explanation

Making Measurements

Read Explanation

Chemistry Branches

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