Chemistry problem help..

[dblock05]

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hey guys, I don't know if its ok to post a chemistry problem, but I'm having trouble figuring out how to do this problem...figured I'd give it a shot here.

.The activation energy of a certain uncatalyzed reaction is 60 kJ/mol. In the presence of a catalyst, the Ea is 54 kJ/mol. How many times faster is the catalyzed than the uncatalyzed reaction at 25oC? (Assume the frequency factor remains the same.)

The answer to the question is "11 times". I just don't know how to get it. I've attempted multiple tries, but no luck. I do know that the basic equation for this problem is k=Ae^-Ea/RT where K is the constant, A is freq. factor and Ea is the Activation energy in joules/mol.

If anyone of you want to give it a shot, its really appreciated. .

 

[nihao]

it is 11.26 (k2/K1)

just plug everything into equation

 

[Passion4Sci]

In the army, we called it Plug and Chug.

 

[dblock05]

it is 11.26 (k2/K1)

just plug everything into equation

thanks! I tried that so many times, but I guess I was doing k1/k2 instead. What a bummer. lol

I have another if you guys want to give it a shot...

.How many grams of nitrous acid, HNO2, ..are required to make 750 mL of an aqueous solution with a pH of 2.35? (..Ka = 4.5 x 10.-.4.. for nitrous acid.)


The answer is 1.7g

.

 

[nihao]

Lol, are you studying PCAT?

anyway, the reaction is: HNO2<=>H+ + NO2-
Ka (4.5x10-4)=[10^(-2.35)x10^(-2.35)]/(X-10^-2.35) {X is initial conc of HNO2}
=> X=0.0485M. then (g of HNO2)/48 g/mol=0.0485 mol/L x0.75 (L) => 1.74g of HNO2

 

[dblock05]

No, I am studying for my chem 2 final on Monday morning. Thanks for the help! It is appreciated.

 

[nihao]

No, I am studying for my chem 2 final on Monday morning. Thanks for the help! It is appreciated.

No problem, glad I am still able to quickly do these things that I learned 2 years ago. GL on your exam!

 

[pharm B]

These kinds of posts aren't allowed on SDN. This falls under "homework help."