Aamc 8 ps #15

[letaps]

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Hey,

I don't understand why C would not be correct, because according to Le Chatelier's principle, won't increasing the concentration of the reactants push the reaction toward the products, thus increasing the reaction rate.
The solution in Tube 1 turned dark blue more rapidly than did the solution in Tube 4, because the:

A) rate of Reaction 2 was slower in Tube 1 than in Tube 4.

B) average kinetic energies of I–(aq) and S2O8–(aq) were greater in Tube 1 than in Tube 4.

The reaction conditions for tubes 1 and 4 are identical except Tube 1 was run at 22ºC and Tube 4 was run at 12ºC. The higher the temperature, the greater the average kinetic energy of the components of the reaction. Thus, B is the best answer.

C) concentrations of I–( aq) and S2O8–(aq) were greater in Tube 1 than in Tube 4.

D) concentration of starch was greater in Tube 1 than in Tube 4.

 

[capn jazz]

C is incorrect because the tubes have identical concentrations of the reactions.

 

[letaps]

so, how do we know they both have the same number of moles?

Also, if the concentrations were different, than increasing the reactant concentration would affect the reaction rate right?

 

[capn jazz]

Yup, due to Le Chatelier's. Look at the top few links on this page and click on the one that says "AAMC tests" or something similar, and try to only post your questions from AAMC exams in the specific thread that is for that test.