An investigator is told that a closed vessel holds a pure rare gas. She measures the density of the gas in the vessel at 298 K and 1 atm pressure and finds it to be 0.8252 g/L. If she assumes that the vessel contains a pure gas, what gas does the investigator think is in the vessel? After turning in her report, she is told that the vessel actually contains a mixture of He and Ar. What percentage of the gas in the container is He?

An investigator is told that a closed vessel holds a pure rare gas. She measures the density of the gas in the vessel at 298 K and 1 atm pressure and finds it to be 0.8252 g/L.

1. If she assumes that the vessel contains a pure gas, what gas does the investigator think is in the vessel?

2. After turning in her report, she is told that the vessel actually contains a mixture of He and Ar. What percentage of the gas in the container is He?