A gas has an initial volume of 168 cm3 at a temperature of 255 K and a pressure of 1.6 atm. The pressure of the gas decreases to 1.3 atm, and the temperature of the gas increases to 285 K.

Use the combined gas law, which gives V₂ = V₁(P₁/P₂)(T₂/T₁) when the amount of gas stays constant. Substituting the values gives V₂ = 168 × (1.6/1.3) × (285/255) ≈ 231 cm³. The final volume is therefore 231 cm³, choice D.

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