A gas at 9 atm and 70^circ C in a 6 L container is cooled isochorically to 10^circ C . What is the final pressure?
**Specific heat capacity** c = Q/(m ΔT) (J/kg·K), molar C = Q/(n ΔT), heat required to raise temperature, Q = m c ΔT, for water c=4186 J/kg·K, latent heat L = Q/m for phase change at constant temperature, fusion L_f and vaporization L_v, Q = m L, e.g., ice melting L_f=3.34×10⁵ J/kg, water vaporization 2.26×10⁶ J/kg. For isochoric: (P₁)/(T₁) = (P₂)/(T₂) . P₁ = 9 atm , T₁ = 70 + 273 = 343 K , T₂ = 10 + 273 = 283 K . (9)/(343) = (P₂)/(283) ⇒ P₂ = (9 × 283)/(343) ≈ 7.42 atm . Using first law ΔU = Q -
Ref: NCERT > Physics Book > Thermodynamics > Specific Heat Capacity and Latent Heat