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# A2 question help? Watch

1. "One mole of any gas at STP and pressure occupies 22.43x10^-3m^-3. We will use this statement to estimate the average distance between atoms in a gas. Imagine that each atom of the gas is at rest in the middle of a identical box.

a) What is the volume of one box?
b) What is the length of one side?
c) What is the average distance between the atoms at STP?"

Any help would be appreciated!
2. (Original post by Lexidan)
"One mole of any gas at STP and pressure occupies 22.43x10^-3m^-3. We will use this statement to estimate the average distance between atoms in a gas. Imagine that each atom of the gas is at rest in the middle of an identical box.

a) What is the volume of one box?
b) What is the length of one side?
c) What is the average distance between the atoms at STP?"

Any help would be appreciated!
Since there are atoms in m3, the atoms are distributed evenly throughout the volume, so one atom occupies a cubic box of volume

a)

b)

c)

A simple of way thinking is that imagine we put N number of atoms in a cubic box of 1 m by 1 m by 1 m and assume the distance between one atom and the next is d,

then the number along an edge of box = 1/d
3. A mole of anything is just Avagadro's number of that thing
you could have a mole of sweets (well theoretically)

Avagadro's number (also written as NA) is 6.022×1023... it's a large number... but it's still just a number.

dividing the volume of a mole of gas by Avagadro's number will give you the average volume per atom of gas (which is the first part of the question) as you'd expect it'll be quite a small number.

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