Prompt#9 Accomplishment of Chemical Engineers

About the significance of chemical engineering, it has much more positive impact than people expected. In the past several decades, our chemical engineers actually are constantly enhance the life of people.

Energy, everything are rely on it. Without energy, the modern society built by us will become nothing. In the last contrary, the main source of energy is depend on the burning of wood and coal. One weakness is that burning coal and wood has a really low efficiency. A lot of energy which is heat will distribute into atmosphere rather than use in where it should be. Second is it will create air pollution. The coal people burned usually are not pure carbon coal. It also has sulfur which will create another bad effect--acid rain.

So, right now, our chemical engineers not only revise the burning way but also invent a lot of other way to supply energy. For burning way, before burn the coal, we will "clean" it by chemical reaction. Also, we will put some basic solution in the chimney to neutralize the acid gas such as SO2. For other ways, we have primary cell and electrolytic cell to produce and store electricity; we have nuclear energy by react radioactive element; also we invent various device to transfer renewable energy such as wind and solar energy to energy people want. I can say chemical engineers contribute a lot for broaden our energy source options.

There are a lot of other achievements done by chemical engineers, please check out this website: http://www.che.ncsu.edu/information/documents/ten_achievements.pdf

pH

Usually, people will measure the concentration of  H⁺ in solution to determine the acidity, and measure the OH^- in solution to determine the basicity. But if people use the number like 1.0*10⁷, it is not simple enough to directly show the acidity and basicity. So, scientists create a way to help us understand the acidity and basicity concisely, that is pH scale.
pH=-log₁₀[H⁺]
For example, if a solution has 1.0*10⁷ M H⁺, then the pH=-log₁₀[1.0*10⁷]=7.

At the same time, we also have pOH.
pOH= -log₁₀[OH^-]
For example, if a solution has 1.0*10⁸ M OH^-, then the pOH=-log₁₀[1.0*10⁸]=8

However, generally, people only use pH instead of using both pH and pOH. The relationship between pH and pOH:  pH+pOH=14 (at room temperature 25。C)
That is because the product of concentration of H⁺ and OH^- always equal to 1.0*10^-14 M at 25。C.
[H⁺][OH^-]=1.0*10^-14 M 
So, we can know the pOH just by using 14 subtract the pH, and do not have to measure the concentration of OH^- in the solution.

Image from: Acids-and-Alkalis-The-pH-Scale.png

Prompt#8 Hand-on Experience

Being a engineer so far, the feeling that building a actual prototype is much harder than I used to think. We always have a lot of ideas during design process, some are really creative and original. But when we need to build a prototype to show our ideas, various problems appeared.

In my EGR 100 class, my second project is to create a system that help students move-in and move-out during the beginning and end of each semester. At first, our team come up with 3 ways to fix the move-in and move-out problem. After discussion, the final design is that we will set a pair of track on the stairs and put a winch on the destination floor to pull the cart that contains the belongs of students. In the platform, we put a turntable to help cart turing.

When we build the model of this design, it just cannot works due to all kind of reasons like the wrong proportion, wrong material and so on. And we need to put a lot of effort to revise it and change it until it works. About proportion, we chose to ignore most of stairs and only do part of it, because the rest of stairs basically are the same as the stairs appeared in our prototype. The biggest challenge of our prototype I think is how to build a turntable in the platform. We use a circled wood put on the platform and use a nail to attach on the platform. At first, the circled wood is too big, sometimes it will stock by stairs. So we made a smaller one instead. And then, our circled wood is too thick to turn. So, we just made it thiner one. Anyway, after a serious work, our prototype finally worked even though it is not 100 percent show our idea. So, coming up with ideas sometimes is actually easier than to make a prototype. If people want reveal their entire ideas in prototype, then it need a huge number of works.

Le Châtelier's Principle

As chemists, we always want to use our knowledge to produce valuable products as much possible as we can. A French chemist, Le Châtelier find a super useful principle:
If a system at equilibrium and disturbed by a change of concentration of chemicals, temperature and pressure, the system will shift its equilibrium to a certain direction.

More specifically, if we add reactants into system, which means the concentration of reactants enhanced, the reaction will shift from reactants toward the products. Vice versa.
If we contract the pressure of system, the reaction will shift to fewer gas direction. Vice versa.
If we increasing the temperature, the reaction will shift toward right if it is a endothermic reaction and will shift toward left if it is a exothermic reaction.
      Image from The Central Science 13th edition

So, our chemists can according to our need, change the temperature, pressure and concentration to product more target chemicals.

Prompt#7 Some Controversial of Engineering field

Look though the entire engineering field, there are one particular engineering field that is controversial for public.

Image from: genetic_engineering_gm_encyclopaedia.jpg

Genetic engineering. Genetic engineering, also called genetic modification, is the direct manipulation of an organism's genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism. Genes may be removed, or "knocked out", using a nuclease. Gene targeting is a different technique that uses homologous recombination to change an endogenous gene, and can be used to delete a gene, remove exons, add a gene, or introduce point mutations. (Wikipedia)

One of ethic code of engineering ask us to enhance entire human being's welfare. What genetic engineers do is changing the DNA of creatures to create a better species. It indeed works, and right now it already apply to come field such as agriculture. But, even though it works, we still not sure the side effect of changing the original DNA of a species. Also, no one knows whether the transgenic food that eaten by human has side effect. That is why make it been such controversial. On the one hand, it indeed can double or even triple output we need and can make species in a way that we want. O the other hand, is it really good for us just to change the nature DNA of a species. The mother nature make a certain DNA for a species must have its reason. Will there be some genetic disasters that create by our human selves one day? These problems are need to be further take consider. Maybe it is fine right now, but who can promise it will fine in the future? It is need controversial!!!!

Seeking for more info? Check out the link below!!!!
http://www.imanengineer.com/exploring-two-of-engineerings-most-controversial-ideas

Haber Process

Nitrogen, carbon and oxygen are 3 extremely important elements that control the growth of plants. Plants can absorb carbon through the carbon dioxide in the atmosphere, and can absorb oxygen through the water. But for nitrogen, it is not easy to obtain because the nitrogen in the atmosphere are unusable for plants even though 78% of atmosphere are nitrogen. The nitrogen in the atmosphere are triple bond molecule, the chemical bond between them are so strong that plants cannot break them.

Image from: Fritz_Haber.png

Until 20th century, the Germany chemists Fritz Haber and Carl Bosch created a most efficient way to transfer the nitrogen in atmosphere to a useful version for plants.
N₂(g)+3H₂(g)à2NH₃(g) 

This reaction is called haber process, which still used to produce the fertilizer nowadays. The principle of this reaction is using Le Châtelier's Principle that I will talk next week. Basically, to produce more NH₃  we just need constantly put more N₂ and H₂ into reaction container and take off the NH₃  Because by adding reactants, it increases the concentration of N₂ and H₂. And by taking off NH₃, it reduces the concentration of NH₃. These 2 movements force the chemical equilibrium shift toward to right which is a direction that will create more NH₃.

Prompt#6 Ordinary of Chemical Engineering

In the past several decades, the chemical engineering field has gone through a dramatic changes.

We are no longer a discipline largely coupled to a single industry, namely the petrochemical industry. Rather, graduates go to a wide variety of industries, including chemicals, fuels, electronics, food and consumer products, materials, and biotechnology and pharmaceutical industries. Moreover, the character of the chemical industry has changed significantly, particularly in recent years. The chemical industry today is very much a global enterprise; companies have been reshaped by a series of mergers, acquisitions, and spin-offs; some major chemical companies have become life-science companies and spun off their chemical units; and the time to market for new products has been significantly shortened.(Armstrong)

Chemical engineer is really a common field and a lot of people right now are willing to choose enter this field. One reason is that chemical engineering is not a academic major, it is a practical job. Many companies are need chemical engineers and people can earn money being a chemical engineer. Second, it has a lot options. Biological related job, medical related job, chemical related job and so on are the career options for chemical engineering. From a big chemical factory to a food factory, we all can see the appearance of chemical engineers. 

Works Cite:

Armstrong, Robert C. "The Chemical Engineering Evolution: What Comes Next?" Chemical Engineering Progress 103.1 (2007): 1. ProQuest. Web. 17 Apr. 2016.

Chemical Equilibrium

Chemical equilibrium is a dynamic equilibria in chemical reaction, which means the rate from reactants to products (forward rate) equals the rate from products to reactants (reverse rate).
Example:
2NO₂ßà N₂O₄
Forward reaction: 2NO₂à N₂O₄  Rate forward=K_f[N₂O₄]
Reverse reaction: N₂O₄à2NO₂  Rate reverse=Kr[NO₂]²

Chemical equilibrium occurs when  Rate forward equals Rate reverse.

Image from: Equilibrium.gif

Here are 3 important phenomenons and conditions to sustain a chemical equilibrium:

• At equilibrium, the concentration of products and reactions are unchanged.
• To keep the chemical equilibrium, neither products and reactants can escape from the system.
• The ratio of both forward and reverse reaction is a constant. 

The first one and second is easily understand. It just like we put the same weight object on each side of scale. If we change the weight of one side, then the scale will not balance. So, to keep the equilibrium, we need make sure the concentration of each substances unchanged. Keep reactants and products escape from system actually is keep them concentration unchanged. The ratio of forward and reverse reaction is decide by coefficients of reaction. Hence, for a certain reaction, the coefficient is certain, and the ratio is certain which is a constant.