Answer: T c = 8a/27Rb.
- A T<sub>c</sub> = 8a/27Rb
- B T<sub>c</sub> = a/Rb
- C T<sub>c</sub> = 27a/8Rb
- D T<sub>c</sub> = a/27Rb
Correct answer: A. T<sub>c</sub> = 8a/27Rb
Explanation: From the van der Waals equation the critical constants are T<sub>c</sub> = 8a/27Rb, P<sub>c</sub> = a/27b<sup>2</sup> and V<sub>c</sub> = 3b.
Boyle's law: at constant temperature the pressure of a fixed mass of gas is inversely proportional to its volume (P ∝ 1/V), so the P–V plot is a hyperbola — halving the volume doubles the pressure. Image: Reginaprice2013, CC BY-SA 3.0, via Wikimedia Commons.
Concept context
Discover why gases expand to fill any container while liquids flow and solids hold their shape. Master the gas laws, the ideal gas equation, and the reasons real gases deviate from ideal behavior.