In a sequential convergence multicomponent simulation program for distillation, the loops are nested. The outermost loop is mole fractions, next is flow rates, and the innermost loop is temperature.

1. Mole fractions are the outermost loop because:

a. Many distillation problems can be done without this loop.

b. Changing mole fractions often do not have a major effect on \(\mathrm{K}\) values.

c. Mole fractions have a major impact on \(\mathrm{K}\) values only for systems with complex equilibrium behavior.

d. All of the above.

2. The temperature loop is done before the flow rate loop because:

a. Temperatures cannot be constant in distillation.

b. Flow rates are often very close to constant in each section of the column.

c. A very good guess of flow rates can be made.

d. All of the above.
3. A good initial guess of the flow rates is to:

a. Assume CMO.

b. Assume the liquid and vapor flow rates are constant throughout the column.

c. Use a bubble-point calculation at the top and bottom of the column.

d. All of the above.
4. For a good initial guess of temperatures:

a. Assume CMO.

b. Use any arbitrary temperature.

c. Use a bubble-point calculation at the top and bottom of the column.

d. All of the above.
5. The mass balances are solved by developing a matrix that is then inverted. The matrix allows one to have feed at:

a. Only one location in the column.

b. Two locations in the column.

c. Any stage within the column but not at the condenser and the reboiler.

d. Any stage in the column and at the reboiler and the condenser.