Sabhi Rajaie

The  first day was the  first moment I was so excited to learn new thing , but somehow I doubt that the subject is quite hard for me. Its not the first time I heard this subject because in 1^st semester I already heard this subject from senior and they said that the subject quite though for engineering student. When I heard that, I was so afraid that I cant score this subject because in 1^st semester I never learn about chemical equation as I should be because I like chemistry. In the first day of Principle of Chemistry class, or we called it mass balance we were briefed by Dr.Aznizam. He is my lecturer until this subject ended . We have been advised to master all the chapter  that we learn in the 1^st semester that is Introduction to Engineering. In this topic, all the calculation that we learn from the 1^st semester we used in  this subject such as convertion. Although he tells us to master it by ourselves , but he always help us in every thing  that we need to remind in the 1^st semester such as volume, density, and much more. The most important thing is unit conversion, it was very helpful to learn new technique that Dr.Aznizam teach us so we can master chapter 3 very quickly .

Next , we learn chapter 4 that is unit process diagram. In  this chapter we must use our last lesson from chapter 3 that is conversion from mass to moles or moles to mass. We also learn new unit such as volumetric flow rates and mass flow rates  that usually used in chapter 4. After  this, we learn the new thing that is mass fraction and mole fraction and its unit. At first I was confuse using many unit that I learn before. After hard time focusing in class and ask Dr about this I finally got the concept. Both of this fraction are used in doing component balance equation for single  and multiple unit system. Besides that, we also learn about concentration and average molecular weight by using data from mass and mole fraction. It was so hard , and I took weeks to master it start from the fundamental things until the new things I that I learn. Everyday quizzes help me to understand and remember what I learn in the class.

Besides that, in chapter 4 also I learn the important things that is material balance equations and flow chart. Everyday Dr.Aznizam advised us to do the flowchart before calculation so that we don`t confuse later. Also noted that in chapter 4 there are classification that is batch, continuous and semi-batch process. Every single thing we learn is operating at steady state when variable in a process are do not change with time and unsteady state for variable changing with time. I must be careful because there are big different between steady state and unsteady state. The following subtopic is general balance equation. Its was important after drawing the flowchart and labeling it. To draw a complete flowchart we must understand it carefully. All the equation are make our calculation become easier to solves. The common technique is algebraic symbols to unknown stream but keep it minimum so that our d.o.f can show that we can solve it. Sometimes , to complete our d.o.f is we using basis. There are two basis , that is starting  the calculation and basis for conversion. It quite challenging  to solve the equation because there are many things to calculate and to many technique to do it. If we start from the wrong equation we can`t solve it. In the following class, we learn bypass and recycle subtopic. The bypass and recyle becomes more harder using more algebraic symbol and complex flowchart. And the concept is the most important because the things that the equation given is not fully straight forward but we must to know it from the concept. Furthermore , I learn about the stoichiometry equation, stoichiometry ration, stoichiometry proportion, limiting and excess reactants, fractional excess, fractional conversion and extent of the reaction. This equation is important to deal in reactive chemical equilibrium equation. For reactive process there are three process that are using molecular, atomic and extent of reaction. The most easy is using atomic species balances. Last but not least, I learn combustion reaction. The combustion is separated into two complete and incomplete combustion. Both reaction have different concept and equation. There are also two different new basis that is dry and wet basis.

Next class, I learn new chapter that is Chapter 5. In this chapter I learn about ideal gas and how to use ideal gas equation. Even though it simple, but the question hard to understand. The calculation is easier but to start it was a bit frustrating at first. Once again the quizzes help me to understand it. For non-ideal gas, critical temperature and pressure very important , instead using n, compressibility factor z will be used. And for the nonideal mixtures, Kay`s rule can be used and its was the last thing I learn in chapter 5.

In chapter 6, I learn about phase diagram. In the phase diagram there are two important thing that is temperature and pressure correspond to a point on the capour –liquid equilibrium curve for the substances. There are many rule I learn in this chapter such as Gibbs Phase rule. After this, we learn about one condensable component. Here we learn new rule such as Roult`s law. Other than this, Dr explain about the superheated condition , dew point and degree of superheat. The next class I learn about multicomponent gas-liquid system. And lastly, I learn energy balance  that still continue until now.