A rigid cylinder with a movable piston contains a 2.0-liter sample of neon gas at STP. What is the volume of this sample when it's temperature is increased to 30 degrees Celsius while its pressure is decreased to 90 kilopascal

This problem is being solved using Ideal Gas Equation.

PV = nRT

Data Given:

Initial Temperature = T₁ = 0 °C = 273 K

Initial Pressure = P₁ = 101.325 KPa

Initial Volume = V₁ = 2 L

Final Temperature = T₂ = 30 °C = 303 K

Final Pressure = P₂ = 90 KPa

Final Volume = V₂ = ?

As,

Gas constant R is constant, so, Ideal gas equation can be written as,

P₁ V₁ / T₁ = P₂ V₂ / T₂

Solving for V₂,

V₂ = (P₁ * V₁ * T₂) : (T₁ * P₂)

Putting Values,

V₂ = (101.325 KPa * 2 L * 303 K) : (273 K * 90 KPa)

V₂ = 61402.95 : 24570

V₂ = 2.499 ≈ 2.5 L