Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 20: Problem 50

The space shuttle orbiter utilizes the oxidation of methylhydrazine by dinitrogen tetroxide for propulsion: \(4 \mathrm{~N}_{2} \mathrm{H}_{3} \mathrm{CH}_{3}(l)+5 \mathrm{~N}_{2} \mathrm{O}_{4}(l) \longrightarrow 12 \mathrm{H}_{2} \mathrm{O}(g)+9 \mathrm{~N}_{2}(g)+4 \mathrm{CO}_{2}(g)\) Calculate \(\Delta H^{\circ}\) for this reaction using data in Appendix \(4 .\)

Short Answer

Expert verified
The standard enthalpy change for the given reaction involving the oxidation of methylhydrazine by dinitrogen tetroxide is approximately \(-4201.3 \space kJ/mol\).

Step by step solution

01

Identify the standard enthalpies of formation for each compound

Look up the standard enthalpies of formation of each compound involved in the reaction in Appendix 4. Here are the values we need: - \(\Delta H_{f}^{\circ}(N_{2}H_{3}CH_{3}(l)) = -80.7 \space kJ/mol\) - \(\Delta H_{f}^{\circ}(N_{2}O_{4}(l)) = 9.7 \space kJ/mol\) - \(\Delta H_{f}^{\circ}(H_{2}O(g)) = -241.8 \space kJ/mol\) - \(\Delta H_{f}^{\circ}(N_{2}(g)) = 0 \space kJ/mol\) (elemental nitrogen is in its standard state) - \(\Delta H_{f}^{\circ}(CO_{2}(g)) = -393.5 \space kJ/mol\)
02

Calculate the sum of standard enthalpies of formation for reactants and products

Use the coefficients in the balanced equation to find the sum of the standard enthalpies of formation for both the reactants and the products: Reactants: \(4 \times \Delta H_{f}^{\circ}(N_{2}H_{3}CH_{3}(l)) + 5 \times \Delta H_{f}^{\circ}(N_{2}O_{4}(l))\) Products: \(12 \times \Delta H_{f}^{\circ}(H_{2}O(g)) + 9 \times \Delta H_{f}^{\circ}(N_{2}(g)) + 4 \times \Delta H_{f}^{\circ}(CO_{2}(g))\)
03

Calculate the standard enthalpy change for the reaction

Now, apply the general formula for the standard enthalpy change for the reaction: \[\Delta H^{\circ} = \sum_{i} \Delta H_{f}^{\circ}(\mathrm{Products}) - \sum_{i} \Delta H_{f}^{\circ}(\mathrm{Reactants})\] \[\Delta H^{\circ} = (12 \times (-241.8) + 9 \times 0 + 4 \times (-393.5)) - (4 \times (-80.7) + 5 \times 9.7)\] \[\Delta H^{\circ} = (-2901.6 + 0 - 1574) - (-322.8 + 48.5)\] \[\Delta H^{\circ} = -4475.6 + 274.3\] \[\Delta H^{\circ} = -4201.3 \space kJ/mol\] The standard enthalpy change for the given reaction is approximately \(-4201.3 \space kJ/mol\).

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

Although the earth was formed from the same interstellar material as the sun, there is little elemental hydrogen \(\left(\mathrm{H}_{2}\right)\) in the earth's atmosphere. Explain.

Arsenic reacts with oxygen to form oxides that react with water in a manner analogous to that of the phosphorus oxides. Write balanced chemical equations describing the reaction of arsenic with oxygen and the reaction of the resulting oxide with water.

What is a disproportionation reaction? Use the following reduction potentials $$ \begin{aligned} \mathrm{ClO}_{3}^{-} &+3 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{HClO}_{2}+\mathrm{H}_{2} \mathrm{O} & & \mathscr{E}^{\circ}=1.21 \mathrm{~V} \\ \mathrm{HClO}_{2}+2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{HClO}+\mathrm{H}_{2} \mathrm{O} & & \mathscr{E}^{\circ}=1.65 \mathrm{~V} \end{aligned} $$ to predict whether \(\mathrm{HClO}_{2}\) will disproportionate.

Beryllium shows some covalent characteristics in some of its compounds, unlike the other alkaline earth halides. Give a possible explanation for this phenomenon.

Many oxides of nitrogen have positive values for the standard free energy of formation. Using NO as an example, explain why this is the case.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Reactions

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Inorganic Chemistry

Read Explanation

Kinetics

Read Explanation

Chemistry Branches

Read Explanation

Making Measurements

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