Homework Question 5G.9, Part B

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Michelle N - 2C
Posts: 117
Joined: Wed Sep 18, 2019 12:19 am

Homework Question 5G.9, Part B

Postby Michelle N - 2C » Tue Jan 07, 2020 7:09 pm

Hello! So the textbook question states:

"A sample of ozone, O3, amounting to 0.10 mol, is placed in a sealed container of volume 1.0 L and the reaction 2 O3(g) S 3 O2(g) is allowed to reach equilibrium. Then 0.50 mol O3 is placed in a second container of volume 1.0 L at the same temperature and allowed to reach equilibrium. Without doing any calculations, predict which of the following will be different in the two containers at equilibrium. Which will be the same? (a) Amount of O2; (b) partial pressure of O2; (c) the ratio PO2/PO3; (d) the ratio (PO2)3/(PO3)2; (e) the ratio (PO3)2/(PO2)3. Explain each of your answers."

Can someone explain about part B? I'm confused about partial pressure and concentration. I know that they're not the same, but what sets them apart? How can I approach problems like these? Thank you!

Asha Agarwal 1E
Posts: 51
Joined: Fri Aug 30, 2019 12:16 am

Re: Homework Question 5G.9, Part B

Postby Asha Agarwal 1E » Tue Jan 07, 2020 8:04 pm

Basically, part B is asking if everything but the amount of reactant in a container stays the same and more reactant is placed in a 1 L container, how will the partial pressure of the product, O2 change. For problems like these, it is asking how changing one piece of information can affect the result of the reaction. In this case, one way to approach the problem is by using the ideal gas law equation and seeing what would happen when n(moles) is increased when everything else stays the same.

Brooke Yasuda 2J
Posts: 102
Joined: Sat Jul 20, 2019 12:17 am

Re: Homework Question 5G.9, Part B

Postby Brooke Yasuda 2J » Wed Jan 08, 2020 10:36 am

A way you could look at it is either that in the second experiment there is a greater number of moles of O2 within the same volume so the partial pressure of O2 must be larger as well. Or you could look at it in the perspective of equilibrium constants. For the system to be at equilibrium, the Kp must remain constant so long as this is the same reaction and the temperature has not changed. As a result, the partial pressure of O2 must be larger in the second experiment because Kp is a constant.


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