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Workbook Quiz 3 #10

Posted: Sat Dec 05, 2015 12:28 pm
by 904564128
The question asks: for the reaction at equilibrium, HCl + I2 <--> HI + Cl2, how will an increase in the pressure (by decreasing the volume) effect the concentration of Cl2?
I found this question a little confusing because in the course reader (p. 129), it says that if the pressure double, the concentrations of the gasses all double and the reaction shifts to the right. But then further down on the page is says that there is no change in concentration. So for the question stated above, does the concentration of Cl2 increase or not change and how could I tell exactly what the question is asking for?

Re: Workbook Quiz 3 #10

Posted: Sat Dec 05, 2015 12:42 pm
by Chem_Mod
You must identify which side of the balanced chemical equation has fewer moles of gas species. After balancing the equation, there will be 2 moles of gas on the left and 3 moles of gas on the right. Thus, a decrease in volume of the reaction vessel will favor the side with few moles making the concentration of Cl2 decrease.