Answer to Question #91424 in Molecular Physics | Thermodynamics for Alexis

Question

How many molecules are there in a sample of gas
that occupies a volume 9 L at STP.
3.428e23
2.42e23
4.55e23
0.753e23
1.372e23

Answer 1

At STP (0°C and 1 atm), one mole of any gas occupies a volume of 22.4 L. One mole of a gas is equal to 6.022e23 molecules (Avogadro's number). Then 1 L of gas contains 6.022e23/22.4=0.26884e23 molecules, and in 9 L of gas contains 9×0.26884e23=2.42e23

Answer: 2.42e23