At 20°C, the density is 1.20g/L. Nitrogen's density is 1.17 g/L. Oxygen's density is 1.33 g/L.?

Question

a) will balloons filled with oxygen and other balloons filled with nitrogen rise or sink in air?

b) air is mainly a mixture of nitrogen and oxygen. Which gas is the main component? Explain how you have come to this conclusion.

Answer 1

Oxygen filled balloons will sink, nitrogen ones will rise.

Nitrogen is the main component (78%). I've known that forever, but if you want the scientific explanation, Dalton's Law of Partial Pressures explains it, in that the overall presssure is equal to the partial pressure of each gas times its mole fraction. You can use the Ideal Gas Law to figure out that pressure and density are related (density = mass/volume = pressure * molar mass / gas constant * temperature) so the gas that has the highest mole fraction will have its density be closest to the overall density, which in this case is nitrogen.

Answer 2

Nitrogens Density