2.5.3 Test (TS): Teacher-Scored Unit. Complete Solution

2.5.3 Test (TS): Teacher-Scored Unit Test Test




Chemistry (2018) Sem 2 (S5129698) Yu Jin Jeong



In this test you will apply what you have learned in the unit. Please answer the questions below.
Submit this sheet to your teacher when you are done.



Question 1: Equilibrium (11 points)



a. Use the CO2 phase diagram to answer the following questions. (4 points)




Triple
point



i. Circle the triple point on the CO2 phase diagram. Describe what is happening at the triple
point. (2 points)

Solid, liquid, and gas phases meet; it is the temperature and pressure at which a
given substance can assume any of the 3 usual phases of matter.



ii. How does the triple point represent a dynamic equilibrium? (2 points)




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, Dynamic equilibrium occurs when equilibrium is maintained by equal rates of
forward and reverse reactions, as opposed to equilibrium maintained by the absence of
reaction. In the case of the triple point, the equilibrium is dynamic.

b. Use the reaction 2CO(g) + O2(g) 2CO2(g) for the following questions. (7 points)



i. Write the equilibrium constant for the reaction. (1 point)

Keq=[CO2]2/ [CO]2 [O2]



ii. What does Le Châtelier's principle predict would happen to the equilibrium conditions if
CO2 were added to the system? (1 point)

According to Le Chatelier's principle, adding additional reactant to a system will
shift the equilibrium to the right



iii. What would happen to the equilibrium if the pressure were increased? (1 point)

When there is an increase in pressure, the equilibrium will shift towards the side of
the reaction with fewer moles of gas.



–4 –2 –4
iv. A gas mixture contains 4.8 10 M CO and 3.5 10 M O2, and Keq = 3.58 10 .
What would the equilibrium concentration of CO2 be at these conditions? (2 points)
–12
2.89 10 M CO2



10
v. If at another temperature the Keq = 8.28 10 , would the reaction favor product
formation or reactants? Explain your answer. (2 points)

The reaction would favor the product formation since when K is large, there is a
larger ratio of products to reactants, hence the reaction favors the product




Question 2: Acids and Bases (10 points)




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