Question

A sample of neon effuses from a container in 73 seconds. The same amount of an unknown noble gas requires 149 seconds.
Identify the gas.

Answers

bobpursley
Use Graham's law of effusion.

rateX/rateNe= sqrt (molmassNe/molmassx)

solve for mole mass of x.

Now notice this: rate above is volume/time

You are given time. So if you want to plug in the given times, the equation becomes

time1/timeNe=sqrt(molmass1/timeNe)

nikki
i am not doing it right , first i got Hydrogen and then Helium...im not sure what im doing wrong
bobpursley
149/73= sqrt(molmassX/20.18)
molmassX=4.16*20.18

The closest Nobel element is Radon.
Ben
The closest would be Krypton, not Radon
cat
wouldnt the equation be 149/73=sqrt(20.18/molar massx)
Kris
No it is inverse
Morgan
How did you get the 4.16?
Matt
149 Ne/73 unknown = sqrt(MM unknown/20.183)
Square root the denominator

2.0411 = sqrt(MM unknown)/ 4.4925
multiply the denominator to isolate the unknown

2.0411 x 4.4925 = sqrt(MM unknown)

9.16972 = sqrt(MM)
Square both sides,

84.083 = unknown molar mass, closest element is the noble gas Radon.
Matt
Bleh, I meant Krypton, not Radon.

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