A 4.25 L flask holds 3.46 mol of carbon dioxide at 229 degrees C. What pressure does the ideal gas law predict?

1. Rearrange PV = nRT to give P = nRT / V. 2. Convert the temperature to kelvin: 229 + 273 = 502 K. 3. Multiply moles by R: 3.46 mol x 0.08206 L atm/mol K = 0.2839 L atm per K. 4. Multiply by the temperature: 0.2839 x 502 = 142.5 L atm. 5. Divide by the volume: 142.5 / 4.25 = 33.5 atm. 6. The value 32.4 atm is what the van der Waals equation gives for the same sample, so it is the near miss set here. 7. Working in Celsius rather than kelvin would give about 15.3 atm, less than half the true answer. _Source: OpenStax Chemistry (CC BY 4.0), Ch 9 "Gases", section 9.6 Non-Ideal Gas Behavior_