Consider a 1.0-l flask containing neon gas and a 1.5 l flash containing xenon gas. both gases are at the same pressure and temperature. according to avogadro's law, what be said about the ratio of the number of atoms in the two flasks?

2 : 3

Avogadro's law states that if two different gasses have the same pressure, temperature and volume, then they will have the same number of molecules. And since xenon and neon are both noble gases, their molecules have exactly 1 atom each. Since both gasses are at the same pressure and temperature, they will both have the same number of atoms per volume. So the ratio of the atoms for each gas will be the same as the ratio between their volumes. And that ratio is:

1 : 1.5

We can multiply both numbers by 2 in order to get a nice integer ratio without changing the value, so we get

2 : 3

Therefore the ratio of neon to xenon is 2 : 3.