Practice Problem: Density of a Gas

The video tutorial explains how to identify an unknown gas using its density, temperature, and pressure. It involves using the ideal gas law (PV=nRT) to calculate the molar mass of the gas. By assuming a volume of one liter, the tutorial demonstrates how to convert pressure units, calculate moles, and determine the molar mass. The calculated molar mass of 4.0 grams per mole leads to the identification of the gas as helium, based on its atomic mass.

What is the initial step in identifying the unknown gas in the problem?

• Calculate the volume of the gas

• Determine the molar mass of the gas

• Use the ideal gas law to find moles

• Convert temperature to Fahrenheit

Which unit conversion is necessary when using the ideal gas law in this problem?

• Grams to kilograms

• Celsius to Kelvin

• Liters to milliliters

• Torr to pascals

What is the value of the gas constant R used in the calculations?

• 8.314 liters atmospheres per mole Kelvin

• 8.314 joules per mole Kelvin

• 0.0821 liters atmospheres per mole Kelvin

• 0.0821 joules per mole Kelvin

How is the molar mass of the gas determined in this problem?

• By dividing the mass by the number of moles

• By multiplying the number of moles by the gas constant

• By dividing the mass by the volume

• By multiplying the density by the volume

Which gas is identified based on the calculated molar mass of 4.0 grams per mole?

• Helium

• Oxygen

• Hydrogen

• Nitrogen