Chemical Equilibrium Part 4 Question 13

Moderators: Chem_Mod, Chem_Admin

TimVintsDis4L
Posts: 104
Joined: Sat Aug 17, 2019 12:17 am

Chemical Equilibrium Part 4 Question 13

Postby TimVintsDis4L » Tue Jan 21, 2020 6:25 pm

I've been doing the following problem and I feel like I am doing it right, but the results say it is wrong. I would assume that i is neither since the moles are equal on both sides. The pressure increases with the volume decreasing so the chemical reaction would favor the side with less moles but that is not an option. What am I doing wrong?

State whether the equilibrium shifts towards products, reactants, or neither when the given change occurs.
2 HI(g) + Cl2(g) ⇌ 2 HCl(g) + I2(s) delta H° = -238.0 kJ.mol-1
i. The volume of the system is compressed.
ii. The temperature of the system is decreased.

A. i = Products, ii = Products

B. i = Products, ii = Reactants

C. i = Reactants, ii = Neither

D. i = Products, ii = Neither

Joseph Saba
Posts: 154
Joined: Thu Jul 11, 2019 12:16 am

Re: Chemical Equilibrium Part 4 Question 13

Postby Joseph Saba » Tue Jan 21, 2020 6:50 pm

I believe part a is correct, treat heat as a product and apply le chatlier.

Prasanna Padmanabham 4I
Posts: 111
Joined: Thu Jul 25, 2019 12:17 am

Re: Chemical Equilibrium Part 4 Question 13

Postby Prasanna Padmanabham 4I » Tue Jan 21, 2020 8:07 pm

I would assume that i is neither since the moles are equal on both sides. The pressure increases with the volume decreasing so the chemical reaction would favor the side with less moles but that is not an option.


I didn't see this at first either, but the I2 in the products has an (s) next to it, so I assume it is a solid (unless it is a formatting computer-error). Solids do not count as "pressure" or "mole of pressure" so the products side has 2 moles of gas while the reactants side has 3 mols of gas.

BNgo_2L
Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

Re: Chemical Equilibrium Part 4 Question 13

Postby BNgo_2L » Tue Jan 21, 2020 8:52 pm

You can also determine whether the reaction shifts left or right when volume is increased or decreased by determining if the concentration increases or decreases. When volume decreases, pressure increases and concentration also increases so Q < K and the reaction will shift right. Vice versa when volume increases.


Return to “Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions”

Who is online

Users browsing this forum: No registered users and 1 guest