Last modified: Wed 12/31/1969 06:00:00 pm
Oklahoma State University

Oklahoma State University

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Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.


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1. Write the formation reaction for each of the following compounds. (Be sure to include the phase for each substance and to give a balanced chemical equation. You may wish to check your textbook for the definition of a formation reaction.) (NOTE: When you enter the equation use the following format: 1/2N2(g) + 1/2O2(g) ---> NO(g). Spaces only occur between phase and + sign or between phase and arrow and arrow and coefficient or formula of product; make the arrow with three '-' and one '>'. Following this format will allow the Expert to most easily recognize your response.)

a. H2O(l)

b. NH3(g)

c. C6H3N3O6(l)

 

2. a. Write a balanced chemical equation for the combustion of one mole of butane, C4H10(g). (Be sure to include the phase for each substance and to give a balanced chemical equation.)

b. Calculate H°rxn for the combustion of butane. (Note you will need a table of standard enthalpies of formation will open in a new tab in your browser.)

H°rxn = kJ/mol

3. When the products are less dispersed in terms of position and energy (have a smaller number of microstates position and energy) compared to the reactants we say S (the change in entropy) for the reaction is negative, and if the products are more dispersed in terms of position and energy (have greater number of microstates position and energy) compared to the reactants we say the S for the reaction is positive. For each of the following reactions predict the sign of S (enter + or -).

a) C2H5OH(l) + 3O2(g) ---> 2CO2(g) + 3H2O(l)

b) H2(g) + F2(g) ----> 2HF(g)

c) 2Fe2O3(s) + 6Cl2(g) ---> 4FeCl3(s) + 3O2(g)

4. Calculate S°rxn for the following reactions. (Here is a table that includes absolute entropies.) (Note: Use the mathematical relationship Watch out, elements have nonzero absolute entropy values. Be sure to check the table above.)

a) C2H5OH(l) + 3O2(g) ---> 2CO2(g) + 3H2O(l) J mol-1 K-1

b) H2(g) + F2(g) ----> 2HF(g) J mol-1 K-1

5. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

6. If there is one question you would like to have answered in lecture, what would that question be?