3. (5 7 point) The label has come off a cylinder of gas in your laboratory. You know only that a homogenous gas is contained in the cylinder, but you don't know what it is. To find it out, you evacuate a 5 -liter flask, seal it and weigh it, then let gas from the cylinder flow into it until the gauge pressure equals 1.00atm. The flask is reweighed, and the mass of the added gas is found to be 13.0g. Room temperature is 27C, and barometric pressure is 1.00atm. What is this gas ( a diatomic molecule) deduced by assuming ideal gas behavior