[aziza]

I realize we are supposed to attempt our homework questions prior to posting them here, but I just had no idea where to start with this one:

Consider a sealed box containing 1.00mol He(g) @ STP.  This box is to be located in Earth's orbit in outer space (surrounded by essentially total vacuum).  The temperature inside the box is maintained @ STP.  Your mission is to drill a hole in one wall of this box such that the He(g) effuses through the hole at an initial rate of 1.00x10^15 molecules per microsecond (10^-6 seconds).  What diameter hold will you drill?

I realize we're dealing with Graham's law...that's about as far as I got before the panic of this question set in.

Any help would be grand, even a little push in the right direction.

Cheers,

Michelle