1O pIS)A large balloon for the Thanksgiving Day parade in New York is filled in

Question

1O pIS)A large balloon for the Thanksgiving Day parade in New York is filled in a 20°C warehouse with He from 50 tanks, each with a volume of 20.0 L and 100 atm of the gas. A cold front arrives on the day of the parade and the temperature on the parade route is -10°C Determine the heat flow (q), work (w), change in internal energy (AE) and change in enthalpy (AH) for the He in the balloon when it is taken from the warehouse to the parade (Assume that He behaves as an ideal gas and that the pressure is constant at 1.00 atm.)

Explanation / Answer

Volume of each balloon, V= 20L, Pressure , P = 1 atm, T= 20deg.c= 20+273= 293K, R=gas constat= 0.0821 L.atm/mole.K

no of moles of helium in each balloon, n=PV/RT =1* 20/(0.0821*293)=0.82 moles

total moles in 50 tanks = 50*0.82= 41 moles

for CP= 5.19 J/gm.K, CV=3.12 J/gm.K

The process is taking place at constant pressure. For constant pressure ,

Q= deltaH= n*Cp*(deltaT)=41*5.12*(-10-20)=-6298 Joules

Work done, W =-nR*(T2-T1)= -41*8.314*(-10-20) =10226 joules

deltaU= Q+W=-6298+10226=3928 joules

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.