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Lyndon's Week 9 WS #7 Clarification Question

Posted: Sat Dec 09, 2017 3:47 pm
by Hena Sihota 1L
Number 7 asks: From number 1, SO3(g)<-->SO2(g)+O2(g). The Kc of the reverse reaction is 5.66*10^(-10). What are the equilibrium concentrations of all the products and reactants if you first introduce a 0.522M sample of SO2 with a 0.633M sample of O2?
I have 2 questions regarding questions similar to this one:
1) Suppose everything in the question was the same except the Kc of the forward reaction was given. You would have to take the inverse of that Kc to get the Kc of the reverse reaction and then solve for x, right?
2) Suppose everything in the question was the same except you were given the concentration of SO3 instead of the concentrations of SO2 and O2. You would have to take the inverse of the Kc given to get the Kc of the forward reaction because in this new scenario the forward reaction would be favored, right?

Re: Lyndon's Week 9 WS #7 Clarification Question

Posted: Sat Dec 09, 2017 4:25 pm
by Chem_Mod
Yes for all your questions. K is usually given for a specific direction. In problems, you will have to determine which direction the reaction is actually going in and make sure the K you are using is correct. Sometimes if you have concentrations of both reactants and products, you will have to solve for Q and compare it to K to figure out which direction the reaction will go.

-L