CH ENGR 101C

## Mass Transfer

*Description:*Lecture, four hours; discussion, one hour; outside study, seven hours. Enforced requisite: course 101B. Introduction to analysis of mass transfer in systems of interest to chemical engineering practice. Fundamentals of mass species transport, Fick law of diffusion, diffusion in chemically reacting flows, interphase mass transfer, multicomponent systems. Letter grading.

*Units:*4.0

###### AD

**Most Helpful Review**

Spring 2020 - Ch Engr 101C with Srivastava was difficult, but not in the way you might expect. I didn't think that the class was more conceptually difficult than, say, heat transfer or momentum transfer, but there was a huge emphasis on math. For example, you might be asked to verify a certain concentration profile, and the math can get pretty tedious as you solved for the integration constants. (I had to use the quadratic formula once to get one integration constant). And the math only becomes worse as you delve into PDEs, which you need to solve through similarity method or separation of variables. Many of us did not have a good foundation with error functions and gamma functions, so it got pretty confusing at times. However, Srivastava was pretty clear in his lectures and with his expectations for the class. I expected to get a B+ in his class because he said that 1 standard deviation above was A- and 2 standard deviations above was A. I was like there's no way I can score 20 points above average on every single exam. But it appears that he lowered the threshold because we did pretty well overall as a class.

**Most Helpful Review**

Spring 2021 - Do you enjoy: 1) Spending eight hours on an exam every four weeks? 2) Carrying out complex differential equations everyday? 3) Having six hours of lecture each week for a class with only four hours of listed lectures? If so, then ask your doctor for a prescription for CH ENGR 101C! ... Please don't. But this is mandatory. We are all nonconsenting patients to this roller coaster ride. --- CH ENGR 101C is what you get if you combine momentum transport from 101A with separation processes from 103 and a slight dab of heat transfer similarities from 101C. Then distilled it into a distillate of 90% 101A before dumping a metric ton of differential equations and integrals and whatever calculus this stuff is from, I sure as hell don't remember. Some people say that CH ENGR 101C is a mass transfer class. I disagree. I literally did not understand like 90% of the concepts taught in class, and this professor sure as hell didn't really try to make us understand. Instead, all we got were equations one after another, correlations, and a bunch of mathematical relationships and models that probably don't reflect real world applications. By the end of the class, I knew how to manipulate every variable involved in mass transfer and utilize their relationships, but I couldn't tell you when to use these equations in the real world or if they are even good estimates. You better remember everything from your multivariable calculus classes, your differential equation classes, and whatever the hell class teaches change of variables, or you'll have a terrible time. --- The grading scheme is pretty simple and consists of: three exams (20% each), homework (30%), and quizzes (10%). Note that the following paragraphs apply to an online quarter. --- Homework are due Friday of each week, and not only focus on material from the previous week, but also includes material LITERALLY TAUGHT THE SAME WEEK. Lectures, and by lectures I mean recordings of last year's lectures, were posted on Sunday of each week, with a "concept class" on Thursday reviewing those lectures. The homework usually includes some advanced applications of the content covered in those recorded lectures, and generally you will need outside help to solve them. Considering that the lecture is posted Sunday night and due the same Friday afternoon, and that students have other things to do with their lives (like other classes), you're going to want to start on it ASAP so you can ask the TA for help if you need it. Otherwise, you'll be screwed pretty heavily, especially since homework grading is harsh and worth a large portion of your grade. --- Quizzes are multiple choice questions related to the Sunday lectures, and are due before the concept class on Thursday. It's very simple, and requires a bit of conceptual thinking, but is easy. Use this to pad out your grades. --- The exams for this class consist of two midterms and one final, located at about Weeks 4, 8, and 11. For the online quarters, these exams were all take home with a twenty four hour window allotted for completion. The exams themselves focused on recent material and were "cumulative" in the sense that the material of each week builds upon the content learned previously, so there are no isolated material that can be solved without prior knowledge. Nevertheless, each individual problem tended to be doable given enough time, and while they are usually difficult and tedious, it works out well. That's because Srivastava is so nice, he especially designed these exams to take only two hours- SIKE. WHAT. DID YOU ACTUALLY THINK THE EXAMS ONLY TOOK TWO HOURS? The exam doesn't take two hours to complete, the problems do. And there are three problems per exam, minimum. So you better reserve like six to eight hours of your life for each exam otherwise you'll have a terrible time. In a top secret interview with the professor on why he thought this was a good idea, his answer was roughly: "well I could finish the exam in two hours, so the students should be able to as well," while neglecting the part where he already knew all the answers and that the proof of some of these problems are three pages long and take half an hour to simply write out. --- In summary, this class is probably one of the hardest, in both difficulty and workload. Hold strong and persist through it though; I believe in you all! We don't want even more people dropping out of chemical engineering.