Question

how cn we calculate the volume of h2 if we know it's diameter?

Answer 1

h2 was supposed to be H2 for hydrogen gas

Answer 2

so the diamter i got is 0.000024

Answer 3

would someone please help me

Answer 4

you want the volume of the molecule?

Answer 5

yeah
would i use v=nRT/p ?

also, the diameter is 0.000024 in cm

Answer 6

nope, that's only used for bulk gases.

If you're approximating the volume of single \(H_2\) molecule, you can model it as a known shape, like a cylinder.

Answer 7

ok, thanks :)

Answer 8

no problem. This isn't for a quantum mechanics class though, is it?

Answer 9

so @aaronq i would try to solve for it by using the volume of cylinder formula? Just to make sure

Answer 10

No, it's just chemistry

Answer 11

but this was assigned from the professor

Answer 12

he came up with the question

Answer 13

we'll it depends what you model it as, it could also be modelled as a sphere, or a combination of cylinder-hemispheres

Answer 14

This is how he wrote it
"Postive (higher) deviation from ideal gas is due to volume of molecules themselves. If H2 has a diameter of 2.4x10^-8 cm what is it's volume? What is the volume in 1 mole of H2 molecules?

Answer 15

he never told the class what model to use....

Answer 16

i would have to multiply Avogadro number by the molar mass of H2 but didn't get the diameter part

Answer 17

ohh, then i think he wants it modelled as a sphere.

for the second part, where he wants the volume of a mole, it's a bit harder. you could make the assumption that there is no space between them and try to pack the spheres next to one another

Answer 18

this type of thing i imagine http://en.wikipedia.org/wiki/Close-packing_of_equal_spheres

Answer 19

So i would use the volume of a sphere to calculate the first one. V=4/3(pi)r^3
ok, the second part i would just have to make assumption based off of that "Close-packing of equal spheres" and no math involved?

Answer 20

Yes for the first part.

For the second, you need to use some math obviously lol

but there are formulas worked out for you, find the volume of a unit cell, then multiply that unit cell to account for all the atoms.

remember we're assuming that the molecules are touching each other, which would only happen in a solid