Review Homework For Equilibrium Test - Revised 2009

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a1. What is the "silly" (one may even call it "stupid") phrase Mr. McLeod makes us memorize to remember the overarching understanding of Equilibrium?

a2. Equilibrium requires a(an) ________________ reaction and a(an) ____________________ system (or container).

b. Define Equilibrium: _______________________________________________________________

c1. When the reaction is "over" what is the main difference about what is in the reaction bucket if one compares a reversible reaction and an irreversible reaction.



c2. What is meant by Dynamic equilibrium?



c3. Why are some reactions reversible and some are irreversible (Hint, has to do with amount of reactant matter and Gibbs free energy)




d. Equilibrium constant value change if you change the _________________________ and ________________.


e. Define Equilibrium positions: __________________________________________________________________

f. At equilibrium, do you have more reactants or products if the K = 1000. ______________________


g. Write the equilibrium constant expression for the following chemical reaction:
2KClO3(s) --> 2 KCl(s) + 3 O2 (g)









h. From your notes, what are the 3 important concepts in Equilibrium?
1)

2)

3)


ia. Define LeChatelier's Principle:


ib. What 2 additional pieces of information (not part of definition) do you need to understand this concept?
1)

2)



j. For the chemical reaction,
2 NO(g) + 1 O2(g) <==> 2 NO2(g) + Energy

Stress: Decreasing temperature (______________________)

How rxn tries to remove stress: _________________________________________________

Circle: Make more product or more reactant (fill in for pressure changes)__________________

Circle: Favoring: Forward rxn or Backward rxn: (fill in for temperature changes) _____________

Circle: Shift Equilibrium to: Left(more reactant) or Right (more product)




k. For the chemical reaction: 2 H2S(g) <--> 2 H2(g) + S2(g)

Stress:Increasing pressure (______________________)

How rxn tries to remove stress: _________________________________________________

Circle: Make more product or more reactant (fill in for pressure changes)__________________

Circle: Favoring: Forward rxn or Backward rxn: (fill in for temperature changes) _____________

Circle: Shift Equilibrium to: Left(more reactant) or Right (more product)




l. For the following chemical reaction in the LeChatlier's Principle Lab,:
(yellow) 2 CrO42- + 2 H3O+ <==> Cr2O72- + H2O (orange)

Stress: Adding in NaOH (_______________________________________________________________)

How rxn tries to remove stress: _________________________________________________

Circle: Make more product or more reactant (fill in for pressure changes)__________________

Circle: Favoring: Forward rxn or Backward rxn: (fill in for temperature changes) _____________

Circle: Shift Equilibrium to: Left(more reactant) or Right (more product)

Solution turned: More Yellow or More Orange or No change

---

m. At 300.degC, the following chemical reaction reaches equilibrium in a 2.50L container.
3 H2(g) + 1 N2(g) <==> 2NH3(g)
At equilibrium, there are 3.25moles N2, 2.75mole H2, and 4.25moles NH3. What is the equilibrium constant (K) and what are its units. (Hint, make sure sure you write down equilibrium constant expression first)




















n. At 25.0deg C, the following chemical reaction occurs in a 0.500L container and has a K=0.0450.
2 H2(g) + 1 O2(g) <==> 2 H2O(g)
At equilibrium, there are 1.49moles H2 and 3.45moles O2. What is the equilibrium concentration of h2O?
(Hint, make sure sure you write down equilibrium constant expression first)


















o. For reaction 2 SO2(g) + O2(g) <--> 2 SO3(g)
a 1.00-L container initially has 3.50 moles of SO2 and 2.00mole O2. If 1.30moles of O2 react to reach equilibrium, what are the equilibrium concentrations of all species and then calculated K (equilibrium constant). Include units of K? 2015-2016 DO NOT DO THIS PROBLEM
















































Answer:
k. K=1.67M-2
L. [H2O]E = 1.66M
m. [SO2]E = 0.900M, [O2]E = 0.700M, [SO3]E = 2.60M, K=11.9M-1


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