CH E 160 SI S’14

Exam 2 Review
Supplemental Instruction
IowaStateUniversity / Leader: / Yee Shiean Tan
Course: / Ch E 160
Instructor: / Stiehl

Engineering Problems

  1. Grapes contain 17wt% solids and 83wt% water. To make grape jelly, crushed grapes and sugar are mixed in a 62:38 mass ratio, and the mixture is heated to evaporate water. After evaporation the jelly contains 28wt% water. Calculate the kg of jelly produced from 4.2 kg of grapes, and the composition of the jelly.
  1. Given the following two sets of data calculate the means and standard deviation of each set. What do the results tell you about the two data sets?

Set A Set B

4.06.1

3.82.4

4.55.2

3.84.2

3.92.1

  1. The set of data was measured to 3 significant digits. Using five data points the given sums that were calculated:

 x = 15.0 (lnx) = 4.78749 (logx) = 2.07918

 y = 178.59 (lny) = 13.2027 (logy) = 5.73387

 (xy) = 766.92 (lnxlny) = 17.61597 (logxlogy) = 3.32258

 (x2) = 55.0 (xlny) = 51.5438 (xlogy) = 22.3852

 (y2) = 12139.9 (ylnx) = 255.631 (ylogx) = 111.019

 ((lnx)2) =6.19950 ((logx)2) = 1.16929

 ((lny)2) = 50.2374 ((logy) 2) = 9.47537

Show your work and use the Method of Least Squares (regression) to:

Calculate the m and b values for an exponential equation and give the equation in general form using correct significant digits (show all of your work).

  1. Solve the following matrix operations:

(a)Rearrange the following equations into matrix form.

7y = x + 3z

30 = 2(2x + y -3z +15)

-3x + 4y + 5z = 0

(b)Calculate the determinant of the above matrix.

Programming

  1. Write only a Functionsubprogram that reads temperature and pressure values in two one dimensional arrays. The function will calculate the moles of gas in a tank using the formula given below:

where V = 0.02 L

R = 0.082 L atm / mol K

The calculated value will be returned to the main program.

  1. Write a Subroutine subprogram that will receive a one dimensional array with up to 50 elements and an integer variable, A which represents the actual number of values in the array. The subprogram will find the largest number in the array and it will also calculate the number of elements in the array that are larger than 0.5 times the maximum value. the subprogram will run return these values to the main program.
  1. A graduate assistant wants to investigate the performance of chemical engineering students of Iowa State University in General Chemistry 1 and 2. The first line of the file contains the number of pairs of points (this number will never be more than 100). The remaining lines contain two numbers each. The first number on each line is the percentage of CHEM177 and the second number is the percentage of CHEM 178. Write a complete program that will read the first line in the data, n, and then read the remaining lines and store the numbers into a two one-dimensional arrays named C1 and C2. The program will then calculate the average of two percentages of each student and store it in a one-dimensional array named Ave. The program will also find the maximum average percentage, and store it in the variable max. Output the array Ave to a file, ExamOut.txt and identify the maximum average by writing the word Max on the line after the value.

Example Output:Example Input:

Work80

36.6 %43.2%30%

11.3 %. . .

76.3 %

.

.

91.9 % Max

. . .