Thermochemistry

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This is a 6 point assignment

Objectives: After completing this unit, students should be able to:

1. Define terms such as energy, work, kinetic energy, potential energy, system, surroundings, state function, and enthalpy.
2. State and apply the first law of thermodynamics.
3. Relate changes in enthalpy to changes in internal energy.
4. Distinguish between exothermic and endothermic processes.
5. Given the change in enthalpy for a reaction, calculate the heat transferred for a given amount of reactant.
6. Using the relationship: q = Sp Ht x m x ΔT, determine the values of one of the variables given the values of the others.
7. Solve calorimetry problems using heat gain equals heat loss and q = Sp Ht x m x ΔT.
8. Calculate ΔH for a reaction given ΔH values for reactions that can be combined (Hess’ Law) to yield the reaction of interest.
9. Calculate the change in enthalpy for a reaction given the standard enthalpy of formation of reactants and products.
10. Write equations that represent the standard enthalpy of formation of a substance.

Reading and Homework Exercises

Table of Contents from: OpenStax Chemistry 2e: Chapter 5

Introduction

5.1 Energy Basics

Questions 1-5 check your understanding of specific heat and heat capacity and your ability to solve problems using these properties. 

Question 1:

Question 2:

Question 3:

Question 4:

Question 5:

5.2 Calorimetry

Questions 6-8 check your understanding of calorimetry problems and your ability to solve problems using the principle of heat loss = heat gain

Question 6:

Question 7:

Question 8:

5.3 Enthalpy

Questions 9 and 10 check your understanding of heat, work, and the first law of thermodynamics

Question 9:

Question 10:

Question 11 checks your understanding of the idea of state functions

Question 11:

Questions 12-15 check your understanding of heat of reaction

Please answer questions 12 and 13 for the reaction:

2 C₃H₆ + 9 O₂ → 6 CO₂ + 6 H₂O

ΔH= -4116 kJ

Question 12:

Question 13:

Please answer questions 14 and 15 for the reaction:

2 H₂O → 2 H₂ +  O₂

ΔH= 572 kJ

Question 14:

Question 15:

Questions 16 and 17 check your understanding of Hess’s Law and your ability to use Hess’s law to calculate heat of reaction:

Question 16: Calculate the heat of reaction (ΔH) for the reaction:

Zn + S + 2 O₂ → ZnSO₄

given the following information:

Zn + S → ZnS    ΔH = -206.0 kJ

ZnS + 2 O₂ → ZnSO₄    ΔH = -776.8 kJ

 

Question 17: Given the gas phase reactions:

NO + O₃ → NO₂ + O₂    ΔH = -198.9 kJ

O₃ → 3/2 O₂    ΔH = -142.3 kJ

O₂ → 2 O    ΔH = 495.0 kJ

Calculate the heat of reaction (ΔH) for the reaction:

NO + O → NO₂

Questions 18-22 check your understanding of Standard Enthalpies of Formation and your ability to use them to calculate heat of reaction:

Question 18:

Question 19:

Question 20:

For the reaction:

2 C₆H₆ (l) + 15 O₂ (g) → 12 CO₂ (g) + 6 H₂O(g)

Using the data in Appendix G, answer the following questions:

Question 21:

Question 22: