! I need some help from my fellow chem geniuses. This is the prob. that has me stuck: The effusion rate of an unknown gas is measured and found to be 31.50 mL/min. Under identical expermential conditions, the effusion rate of O2(oxygen) is found to 30.50 mL/min. If the choices are CH4, CO, NO, CO2, and NO2, what is the indentity of the unknown gas? My book says the answer is NO. but i dont see how the answer is obtain. what steps and equation are used???