Computers have revolutionized the way chemical engineers design and analyze processes, whether designing large units to make polyethylene or small microreactors to detect biological agents. In fact, the engineering problems that many of you will study as undergraduates today are similar in complexity to the problems Ph.D. students solved 30 or 40 years ago. Computer programs can now solve difficult problems in a fraction of the time it used to take. Nowadays, you no longer have to write your own software programs to use computers effectively. Computer programs can do the numerical calcu lations for you, but you will still need to understand how to apply these programs to specific engineering challenges. Thegoal ofthis bookis to help youpractice better chemical engineering. Computers are valuable tools that enable progressive, far-reaching chemical engineering. Unfortunately, computers are not as basic as CD players, where you insert a CD, push a button, and get the same result every time. Sometimes computer programs do not work properly for the para meters you have given them. Therefore, you must be careful to use them wisely