A sample of hydrogen gas (H2) has a volume of 8.56 L at a temperature of 0 degrees C and a pressure of 1.5 atm. Using the Ideal Gas Law, calculate the moles of H2 molecules present in this gas sample.

• A. 0.85 moles
• B. 0.28 moles
• C. 0.57 moles
• D. 1.14 moles

Answer: (C)

Verified step by step guidance

1. Start by recalling the Ideal Gas Law, which is expressed as: $PV=nRT$, where $P$ is the pressure, $V$ is the volume, $n$ is the number of moles, $R$ is the ideal gas constant, and $T$ is the temperature in Kelvin.
2. Convert the temperature from degrees Celsius to Kelvin. The conversion formula is: $T$_k=T_c+273.15. For 0 degrees Celsius, the temperature in Kelvin is 273.15 K.
3. Identify the values given in the problem: Pressure $P=1.5$ atm, Volume $V=8.56$ L, and Temperature $T=273.15$ K.
4. 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.
5. Rearrange the Ideal Gas Law to solve for the number of moles $n$: $n=PVRT$. Substitute the known values into this equation to find the moles of hydrogen gas.