VLE data for the system dichloromethane(1) and methanol(2) at 50oC appear in the table below.Ī.) Make a Pxy Diagram in Excel based on this data. ε, indicating the location of the equilibrium value of ε determined in part (a). For a temperature of 1300 K (the reaction is unaffected by P) and for a feed of 1 mol H2 and 1 mol CO2:Ī.) Determine the equilibrium value of ε by application of Eq.
Data for ΔGof,I for the compounds of interest are given with Ex 13.13. Once the yi are eliminated in favor of ε, Eq. The equilibrium criterion therefore becomes: Applied to the water-gas-shift reaction with the understanding that T and P are constant, this equation becomes : When the Gibbs energies of the elements in their standard states are set equal to zero, Gi = DGof,i for each species, and then :Īt the beginning of Sec. Application of the summability equation to Eq. If no heat transfer takes place during this process, determine the final temperature of the helium in the balloon.Īt high temperatures and low to moderate pressures, the reacting species form an ideal gas mixture. The material of the balloon is such that its volume increases linearly with pressure. Now, the valve is opened and helium is alowed to enter the balloon until pressure equilibrium with the helium at the supply line is reached. The balloon is connected by a valve to a large reservoir that supplies helium gas at 150 kPa and 25oC. Once you have a ref state, use a Hypothetical Process Path from the ref state to states 1, 2 and inlet to evaluate U1, U2 and Hin using the IG EOS and CV and CP given in the problem.įor He, use: CP = 5.1926 kJ/kg-K and CV = 3.1156 kJ/kg-K.Ī balloon initially contains 65 m3 of helium gas at atmospheric conditions of 100 kPa and 22oC. The P doesn't actually matter because He is treated as an IG in this problem so U and H are not functions of P anyway. I want you to use a reference state of U = 0 for He gas at 22 oC and 100 kPa. A reference state is a T, P and phase at which YOU choose to make EITHER U or H zero kJ/kg. In order to do this (just like the steam tables) we MUST choose a reference state. These are NOT ΔU's and ΔH's but real U's and H's. The catch is that we must determine values for U1, U2 and Hin. The equations are: the IG EOS applied to the final state of the balloon and the transient form of the 1st Law applied to this process.
After you determine V2, calculating Wb is easy ! Then, simultaneously solve two equations in two unknowns. Use the IG EOS to determine the initial mass of He in the balloon. Assume the He behaves as an ideal gas, but check to see if this is a good assumption. This is a transient or unsteady process because helium enters the system (the balloon). Plot room temperature as a function of time. Ignoring heat exchange with the surroundings, as well as any changes in kinetic or potential energies, estimate how long it takes for the room temperature to reach 70oF.
The air pressure is essentially 1 atm everywhere. The air is well-mixed within the room and an equal mass flow of air at room temperature is withdrawn through a return duct. In the morning, a worker resets the thermostat to 70oF, and 200 ft3/min of air at 120oF begins to flow into the office through a heating duct. The air supply to a 2000 ft3 office has been shut off overnight to conserve utilities, and the room temperature has dropped to 40oF.