Final answer:
To calculate the volume percentage of helium in the sample of methane gas, calculate the moles of each component and their partial pressures using the ideal gas law.
Step-by-step explanation:
To calculate the volume percentage of helium in the sample of methane gas, we need to first find the moles of each component and then calculate their partial pressures.
Given that the density of the sample is 0.70902 g/L at 0.08°C and 1.000 atm, we can calculate the moles of methane using its molar mass.
Next, we can calculate the partial pressure of helium using its density and the ideal gas law.
Finally, we can calculate the volume percentage of helium by dividing its partial pressure by the total pressure of the gas sample and multiplying by 100%.