A cylinder contains 28.5 L of oxygen gas at a pressure of 1.8 atm and a temperature of 298 K. Using the Ideal Gas Law, how many moles of gas are in the cylinder?

• A. 1.50 moles
• B. 2.10 moles
• C. 3.00 moles
• D. 0.75 moles

Answer: (B)

Verified step by step guidance

1. Start by recalling the Ideal Gas Law, which is expressed as: $PV=nRT$. Here, $P$ is the pressure, $V$ is the volume, $n$ is the number of moles, $R$ is the ideal gas constant, and $T$ is the temperature.
2. Identify the values given in the problem: Pressure $P$ = 1.8 atm, Volume $V$ = 28.5 L, and Temperature $T$ = 298 K.
3. Use the ideal gas constant $R$ = 0.0821 L atm/mol K, which is appropriate for the units of pressure in atm and volume in liters.
4. Rearrange the Ideal Gas Law to solve for the number of moles $n$: $n=\frac{PV}{RT}$.
5. Substitute the known values into the equation: $n=\frac{1.828.5}{0.0821298}$. Calculate to find the number of moles of oxygen gas in the cylinder.