Textbook Problem 5.61; Confused about changing pressures.

[Meghna Sehrawat 3A]

Hi, I didn't get the same answer for 5.61 part B as the book did. Here is the problem. https://drive.google.com/file/d/1ospoXwUyTXeln5PwvdFNbhFxaFsUnCUI/view?usp=sharing

I was confused about what substances you look at for pressure changes. Do you only look at gas then, and disregard the aqueous solution?

[Nathan Chu 2G]

Hello,

The correct answer to part B of that problem is that nothing would happen. This is because when pressure is increased, the reaction shifts to the side with fewer moles of gas. This means that aqueous solutions, solids, and liquids are not considered in terms of shifts due to pressure. In this problem, both sides of the reaction have 6 moles of gas.

Hope this helps! Cheers

[Dashrit_Pandher_1J]

Yeah so when we look at changes in pressure we only focus on the gaseous moles; we disregard the aqueous species in the reaction. Aqueous species vary rarely or contribute very little to a system's pressure, so we are able to just completely exclude them when looking at changes of pressure to the system.