# OldChemE

Senior Members

257

2

1. ## 0÷0

Wrong, unfortunately. 0 divided by 0 is undefined. Why? you might ask? The rule in math is that anything divided by itself is 1. This would argue that 0/0=1. However, zero has peculiar properties that prevent this. For example, 16/16 = 1, but 16 = 4 x 4, so 16/16 is the same as 4x4/4x4. but 4/4 = 1, so 4x4/4x4 = 1 x 1 = 1, and 16/16 = 1. The point of this example is that if we divide a non-zero number by itself, we always get an answer of 1, even if we factor the number. Now, consider 0/0. 50 x 0 = 0, and 1 x 0 = 0, so 0/0 could be 50x0/1x0. if 0/0=1, then this version of 0/0 = 50. The point here is that the answer changes depending on what numbers were multiplied to make zero. This, then, defeats mathematics, which is why the result you are seeking is "undefined" in mathematics. Attempting to divide any number by zero, even zero itself, creates inconsistencies in mathematics, and is not permitted.
2. ## Why do we need vacuum tubes, transistors..why not just use DC?

OK-- I think I see what the OP's question is-- If I'm wrong, forgive me. I think the question is why did we need Vacuum tubes (and later transistors). Prior to the digital revolution, all signals were analog. This included radio and TV. radio/TV signals as received from the air are very weak, and have to be amplified. That was the function of the Vacuum tubes and later transistors-- amplification. Specifically, a small analog signal on the input could be made to produce a duplicate signal with larger voltage swing at the output. Thus, the purposes of these devices was not to transmit voltage to the screen or speaker, but to raise the magnitude of the signal to make it strong enough to drive the speaker or output device. Many modern devices don't require the high voltages so this function is becoming less common.
3. ## From an all exams to an all projects oriented educational system for better learning.

I would be interested in knowing what the statement "absolutely wrong" means? If it means that it is wrong to test problem solving skills, then I would have to disagree-- there is no place in science or engineering for people who do not have problem solving skills. If you mean that the statement is not true, then you are wrong or misinformed. I took exams all through university that required demonstration of problem solving skills and I wrote many, many exams myself as a High School science teacher that required problem solving skills. To paraphrase what I said in my earlier post, the key distinction between a project and an exam is that only in the exam can the teacher know with a fair degree of certainty that the results truly reflect what the student can do, as opposed to what the "student (and friends and internet)" can do. This is important to know. It does not, of course, determine the entire grade, but it is important. Projects cannot provide this degree of insight.
4. ## Computer science is not a science!

I would argue that Computer Science is NOT science, it is Engineering. Pure sciences deal with discovery and explanation of the ways in which things arise, while engineering deals with application of scientific information to real world situations. Clearly (at least in my mind) the things that so-called Computer Scientists do is an application of mathematics and/or electronics and/or physics, which makes it a branch of engineering.
5. ## From an all exams to an all projects oriented educational system for better learning.

The concept that students cram before an exam, instead of learning steadily is not true for many disciplines. In sciences and engineering, exams often focus on the ability of the student to solve problems, rather than on memorized facts. As such, the exam is actually asking students to demonstrate problem solving skills just like those done in class and for homework, with the only distinguishing quality being that during the exam they have to show that they actually have the skills themselves, while in the case of homework they may have completed the work with help of someone else. I believe this is a valid purpose above and beyond projects. Which is why, after I retired from Engineering and took up teaching for 7 years, I built my exams in Science classes just this way, and graded those exams on the basis of demonstrated problem solving skill, not just on correctness of the answer (in fact, in my exams, students were required to show their problem solving methods in order to receive a score-- a numerical result alone, with no supporting calculations, was an automatic zero no matter how correct).
6. ## Timeline for when religion will be obsolete.

Time line when religion will be obsolete?? About the same time that people stop believing in magic, weight loss miracles, and winning money in the lottery
7. ## Equation balancing

EquationsProbles1 Yes, your equation is properly balanced. Your problem with this lies insolubility. Both of your sulfate products are very, very, soluble in water. What this means is that the products never actually form-- the individual ions stay in solution and you can only get the sulfates out by evaporating the water. As for the Ammonium nitrate, it is also soluble in water to the tune of about 20 moles per liter (118 grams per 100 ml according to my old handbook of chemistry and physics). When all the products of a potential reaction are soluble, the final compounds are never formed-- its just a big soup of ions floating around together (and fyi-- If I recall correctly, its not enthalpy that determines if a reaction if favorable, its Gibbs Free Energy, which also takes into account Entropy. All the enthalpy change won't do it if entropy is too unfavorable). I realize I'm violating the homework rules by giving an answer, but this discussion seems to have dragged on.
8. ## Why? the need of an air compressor at a nuclear plant.

In several of the Nuclear Power plants I worked on (designing) we had double valves on all pipelines exiting the reactor containment building. No valve is perfect (they all will leak-- even if only a tiny amount). Safety regulations required that we test the valves periodically to ensure leakage was within the acceptable range. We did this by pressurizing the space between the two valves with compressed air and measuring the rate of air loss. This was a very good test, because normally the lines contain water, so using air amplified the leakage (compared to water) and gave us a test of adequate sensitivity.
9. ## Important concepts and equations in classical physics

The Laws of motion-- definite yes (and for engineers especially the three forms v = v(0) + at, x = x(0) +vt + 1/2 at^2, and v^2 = v(0)^2 + 2a(x -x(0))) Also the various formulas for Kinetic energy, Potential energy, and Work
10. ## Should Religion be banned

As opposed to electing a rich career politician such as a Clinton POTUS??
11. ## Italy makes 12 vaccinations compulsory for children

If you don't like vaccination for childhood diseases, the least you can do is "old world" vaccination. I come from a family of four boys. Every time one of us came down with the standard childhood disease, my mom would fix a really nice breakfast for the sick one, and when he was finished she would feed the other three using the same spoon she used for the sick one (unwashed, of course). There was risk, yes, but at least she knew we were all sick and kept a close eye on us, and took us to the doctor if necessary.
12. ## Solve Physics problem

A good approach. In my physics classes I required my students to use a 5 step process in order to gain full credit for a solution. They had to read the problem and then: 1. Identify the 'Givens' by symbol, numerical value and units 2. Identify the Unknown (the thing to be found), by symbol and units 3. Select an appropriate formula linking the unknown to appropriate givens 4. Perform all unit conversions as necessary 5. Solve, showing the math and presenting the results by symbol, value, and unit
13. ## New Keyboard layout

Qwerty is fine-- it had a purpose. Alphabetical order has no purpose. It's an arbitrary arrangement of faint historical value that has no correlation to the best typing arrangement. I'm not sure qwerty has a lot of correlation to what's best either, but I've learned qwerty and I'm too old to easily change. What I would love to see is for the "CTRL" key to be moved somewhere where it is not so easily reached. I am a fast, but not accurate, touch typist. On many occasions I have accidentally hit the ctrl key when reaching for the shift key, and then the keystrokes that came after the accidental ctrl key have erased whole documents before I even realized that the letter keys I struck after reaching for the shift key (due to my typing speed) were being interpreted by the computer as function commands instead of letters.
14. ## Do plants like music?

I can't speak to the topic of music, but down the street from my house years ago there was an old lady with a very nice garden. She had a sign in front of her plants that said "Grow DAMMIT!"
15. ## Had a few questions regarding MS in Nuclear Engineering

I did my BS in Chemical Engineering, and then a MS In Nuclear Science. By choice, I never got into research type work. However, my experience was that the multi-discipline background you acquire by doing a MS in a different subject from the BS led to many more opportunities for interesting work. There seems to be a great demand in STEM for people with the synergistic ability-- the ability to pull together the pieces using knowledge from diverse fields of study. The funny part is that I enjoyed my career immensely, but never did actually carry a job title of Chemical Engineer or Nuclear Engineer. It depends on what really interests you, but I don't think you can go wrong by staying on the path you are taking.
16. ## Job market of the future

Maybe there won't be a "job Market" Looking at history, "Jobs", as in "go to work" are, for much of the population, a relatively new thing in society. Look at what a large percentage of the US population in the 1800's simply provided for themselves but did not "go to work" anywhere. May be we're headed for a future where what people do is what they choose to do but don't work for someone else as such. I have a relative who technically has a job in that he has a license to sell used cars, and has a auto paint shop on his property,but what he really does is trade his work for other's work, "flip" cars (as in buy, fix, and sell for more), buy and rent out property, and anything else he feels like doing when he gets up in the morning-- and he's providing for his family just fine.

18. ## Are there, or are there not, sentient animals.

To the intent of your question, Yes, I agree with Dolphins as fitting your criteria. However, your choice of word is wrong. The word Sentient derives from the Latin word for "feel" and is already defined in many dictionaries-- your definition is not the correct one. Sentient beings are those that feel things (subjective reaction to their environment)-- which is different from the ability to reason-- which is what I think you are getting at. Most living animals are Sentient. sen·tient ˈsen(t)SH(ē)ənt/ adjective adjective: sentient able to perceive or feel things
19. ## New political party

You can start a party-- but the real problem is gaining majority. This is a huge issue in the USA. In countries where the elected representatives form a government, multiple parties can work, because several parties, each having a minority of the total, can form a coalition to select the leader (such as a Prime Minister). In a system like the US where the President is directly elected separate from the Senators and Representatives, it takes some form of majority (electoral or popular, or both) for party to get someone in office to push their platform and not veto legislation.
20. ## Yellow solid on copper sulphate crystals

Since you used tap water, there are many, many possibilities. But, my first guess is that something in there reduced the sulfate ions, and you now have traces of pure sulfur-- which is yellow.
21. ## Turning Steam Back Into Water

That's a tall order. First problem is that the heat of vaporization/condensation of water is very large-- which is why it is so useful in steam turbines. So-- you need to spray it on something that can take away a lot of heat. I suggest anything that conducts heat really well-- which pretty much means metal of some kind. It would also help to have lots of surface area to promote heat transfer. I'm giving you theory instead of actual details because, in all honesty, I can't think of anything that would work really well in Texas heat.
22. ## Why do shorter people have lower DNA damage and live longer?

The interesting part to me is that in reading the links posted by Swansont the two medical articles kept mixing the topic of height with the topic of diet. In other words, they repeatedly mentioned dietary differences that they implied were responsible to some degree for height differences. So, is it height that is the factor or is it the means by which the height is achieved??
23. ## Amateur question about classical physics - escape velocity

Perhaps a different way of looking at it will help you (a little College Physics) Imagine you launch an object vertically with some starting velocity (tossing a ball in the air). Eventually, it reaches its maximum height and the velocity goes to zero, but the ball now has potential energy due to its height. We find escape velocity by doing this calculation assuming the height we reach is infinity. At infinity, potential energy goes to zero (no longer attracted to the earth), and kinetic energy goes to zero (zero velocity). The equation is 1/2 mv^2 - GMm/R = 0, where m is the mass of the object, M is the mass of the earth, R is the radius of the earth, G is the gravitational constant and v is the starting velocity (escape velocity). You Solve this equation for the value of v and that is the escape velocity. This is conservation of energy and the angle of travel has nothing to do with it.
24. ## What is the difference between killing an animal for fun and killing one for food?

I think there is another way to look at this. I learned long ago not to fear a major surgery when I realized that I would go to sleep (loss of awareness), and if I died on the table I would not know it had happened. Let's apply the same logic here. If an animal is not capable of the human level of thought, and is not aware that it is about to be killed, and its existence is terminated in a way that the animal does have the opportunity to experience pain or loss, is there any moral reason not to use it for food?? I don't think so.
25. ## Why is Chlorine not hybridised in BCL3 using hybridisation concept in VB Theory

In my earlier comment about electronegativity of Chlorine-- I was postulating that since Chlorine is more electronegative than Boron, it holds the electrons shared with Boron more tightly than Boron can. In hybridization, the orbitals of an atom shift to accomodate the bond-- so I'm wondering if the energy efficient approach is for the atom that holds the electrons less tightly to hybridize. You would have to dig into this more to check ti, as I am not an expert on hybridization.
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