About 60% of annual U.S. ethane production is recovered during the processing of natural gas. A sample of ethane (C₂H₆) gas has a volume of 575 cm³ at 752 torr and 72°F. What is the mass of ethane in this sample?

Strategy We are trying to find the mass of a sample of gas. If we knew how many moles of C₂H₆ were in the sample, we could easily use the molar mass to find the mass of the sample. And since the problem involves a gas, we can attempt to use the ideal gas law to find the number of moles. We are given values for V, P, and T, so we will be able to solve for n. Some of the units given are unusual, so we will need to be careful to handle them properly.