Which of the following has to be true based on this process description?
A fresh feed stream contains 50.0mol/s each of A and B and no other compounds. It is mixed with a recycle stream and enters a reactor. The reaction A + B ? C is carried out in the reactor. The reaction reaches equilibrium and 50% of the entering A is converted into C. The reactor effluent is sent to a distillation column. The bottom product from the column is 98.0 mol% pure C and is the product from the process. The top product contains 1.0 mol% C and the entire top product is recycled. The entire process operates at steady state.
A. The recycle stream is 49.5 mol% A and 49.5 mol% B.
B. The equilibrium constant in the reaction is 1.
C. The molar flow rate of the product stream is 50.0 mol/s.
D. All of the above have to be true.
E. None of the above has to be true, though they could be true.
A. Correct. The reaction shown consumes A and B in equal molar amounts, and they enter the process in equal amounts, so they must also leave the system in equal amounts. If they are present in equal amounts in all these streams, they must also be present in the recycle stream in equal amounts—you will find there is no solution to the mole balances if this is not true.
B. Incorrect. If 50% A and 50% B enter the reactor, and half of the entering A is converted into C, then the resulting mixture will be an equimolar mixture of A, B and C. The equilibrium constant expression (assuming ideal solution behavior) is xC/xAxB. If xC=xA=xB=0.3333, then K=3, not 1. (Note that there is in fact a small amount of recycled C entering the reactor, so the equilibrium constant isn’t actually exactly 3, but it definitely isn’t 1.)
C. Incorrect. If the product stream was pure C this would be true—the mole balance on the entire process would be 50 moles of A and 50 moles of B enter per minute and 50 mol/s of C leave. But the product stream also contains some A and B in it, so its molar flow rate is a bit larger than 50.0 mol/min.
D. Incorrect. You can disprove at least one statement.
E. Incorrect. One statement has to be true.
You might also like to view...
Figure 19-03
The accompanying figure shows a detector that uses a tank circuit tuned to the frequency of the oscillator. This type of sensor is a(n) ____________________.
Fill in the blank(s) with the appropriate word(s).
Which of these are two types of mines?
a. Wet and dry b. Permitted and non-permitted c. Surface and underground d. Complete and partial
Processors must either state that a "juice" drink is flavored by the juice or state the amount within _____ of the actual amount of the fruit juice in the drink
a. 1% c. 5% b. 3% d. 10%
Determine i in the circuit of Fig. 10.50.
 FIGURE 1.png)