[theRealDJ]

Okay so i have to do this Gas Density Lab report. In the lab, we used Methane, Oxygen, and Carbon Dioxide. We basically put those gases into a 140mL syringe, and weighed it. Obviously, we subtracted the weight of the syringe from the weight of the syringe plus the gas. So for example, my oxygen number I am using is 0.127g. When i put that in the density formula, D=M/V, and use 140mL. In the protocol, it says use 32.00 as the relative density when finding the % error, but my number comes out really really small. So I then instead decided to use liters. So i did 0.127g divided by 0.14 L. And it still came out below 1. Am I doing something wrong? Even when my teacher was talking about it today, she used rather large numbers as an example. 

[Borek]

32 is not a density, but a molar mass of oxygen. Note: molar mass can be used to easily calculate density of the gas using ideal gas equation (what is the volume of 1 mole of the gas at given T,P?), so it makes sense to use it as a relative density (which is exactly what you wrote, but most likely ignored).

For comparisons you can use either the real density of the gas or the relative density - but you have to be consistent (compare real densities or relative densities, not the real with the relative).

The real density of the oxygen should be a bit above 1 g/L, but definitely below 2 g/L. Have you accounted for the buoyancy?