[jehu3]

I am studying for a test and came across a question using Graham's Law.

I won't bother copying out the whole question.  We are given the time for an unknown element to effuse through a barrier and the time for Cl to effuse at same temp. and pressure.

My understanding is Graham's Law is:

Rate A/Rate B = square root [(Molecular Weight B/ Molecular Weight A)]

So in this case:

Rate Cl/Rate unknown = square root [(Molecular Weight unknown/ Molecular Weight Cl)]
4.3 min/ 5.2 min = square root [(Molecular Weight unknown/ 35.47)]
and so on .

But, the Prof. said that rate is the inverse of time so, the equation should be :

Rate Cl/Rate unknown = square root [(Molecular Weight Cl/ Molecular Weight unknown)]
4.3 min/ 5.2 min = square root [(35.47/Molecular Weight unknown)]


My question is - aren't rate and time the same thing?

[Yggdrasil]

If something occurs at a greater rate, it will take less time to finish.  For example, speed is a rate.  If you are traveling at a faster speed, you will reach your destination in less time than someone traveling at a slower rate.

[Donaldson Tan]

But, the Prof. said that rate is the inverse of time so

Your Prof is right!