xrosein3's Blog
I'm a chemistry teacher trying to help my students become the best.
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Unit 1 Ch. 3 Reading Response
October 27, 2009 by xrosein3
Answer one of the three questions below according to the first letter of your last name as indicated below. Then read others responses so that you are familiar with all answers. Later, after Mr. Powers has given further directions, you will answer the questions that will be on RenWeb concerning these topics.
A-H
Read p. 68 and name the various compounds that the carbon atom was a component of during the course of Levi's story. Be sure to answer in paragraph format
I-Q
The study atomic structure and the nucleus produced a new field of medicine called nuclear medicine. Describe the use of radioactive tracers to detect and treat diseases.
P-Z
Trace the development of the electron microscope and cite some of its many uses. Be sure to talk about why the scanning tunneling microscope is so significant.
Unit 1 Chapter 2 Reading Response
September 29, 2009 by xrosein3
Choose from one of the three questions below to respond to. Remember to respond to two other students as well. You do not have to respond to students who answered your same question. You can respond to students that answered a different question than you did.
1. There are 365 days in a year! True or False? Although we say that a conversion factor has an infinite number of significant figures when we are calculating answers, we don't use all of the figures when doing calculations. You may have thought you knew the conversion factor from days to years (365) but that's not actually very accurate.
What is the real conversion factor?
What information did you already know that would have made you answer False above? Historically, why is there a discrepancy between what we typically use (365) and what the actual value is?
Finally, what is the conversion factor based upon and does that stay the same from year to year?
2. Find out how the metric system, which was once a standard for measurement, differs from SI. Why was it necessary to change to SI?
3. Find out what ISO 9000 standards are. How do they affect industry on an international level?
Re: Unit 1 Ch. 1 Reading Response pp. 8-9
September 11, 2009 by xrosein3
isaachenry, I'm going to have to disagee with your second answer. Just because the rays produce short wavelengths does not mean that they emit energy. The way that it emits energy is the atoms when decaying, release nuclear particles which then changes them into a new element, therefore emiting energy.
-stefbomb17
Actually, these waves are a form of energy. Think about a light wave. We can harness it's "energy" with photovoltaic cells that convert it to electricity.
Think of a wave in the ocean. The wave is only there because something imparted energy to it. (i.e. the wind, a boat, or an earthquake)
Re: Unit 1 Ch. 1 Reading Response pp. 8-9
September 11, 2009 by xrosein3
Guys, you need to realize that if we had the resources to develop gold on demand it would be very numerous and pretty much no different than any other rock because of the massive quantity us selfish humans would produce. Things gain value because of their rarity that's why many of them are called precious metals. The prices of silver and such have fluctuated greatly over the years because of supply and demand, it's as simple as that, supply and demand. If everyone is rich with gold it becomes as worthless as the old techniques of money values. Energy, however, is always in need and is what the world could not survive without. Which do you think the world could survive better without, gold or energy? The answer is obvious. the world runs on energy and is not dependent on a rock.
-ryan34express
Well stated.
Re: Unit 1 Ch. 1 Reading Response pp. 8-9
August 26, 2009 by xrosein3
responding to Mr.Powers (probably does not count for the assignment, considering that the teacher is not a student): How can we come even a small amount closer to discovering our Creator, through learning chemistry? I do agree though that by learning chemistry we come to understand/ realize the complexity and greatness of our God. :)
-bethx
Nevertheless I appreciate the response.
Many people in history have searched for truth in science. Some of these have discovered a complexity so vast as to be illogical but for a higher power that could have constructed it. The very complexity and greatness of our God that you refer to is exactly the thing that leads some people to realize that God must indeed exist.
Re: Unit 1 Ch. 1 Reading Response pp. 8-9
August 26, 2009 by xrosein3
if anyone needs more info on this look on page 720
-courtneysanders
Way to help out, Sandy!
Re: Unit 1 Ch. 1 Reading Response pp. 8-9
August 26, 2009 by xrosein3
1. After this discovery, alchemy was used routinely in nuclear-physics related sciences.
-taylorw
Hmmm, are we sure about this?
Re: Unit 1 Ch. 1 Reading Response pp. 8-9
August 26, 2009 by xrosein3
2. The best answer i can acquire from the reading in the book is that the atoms that make up the rock emit energy when they undergo subatomic chemical change. The energy that the atoms release are radioactive particles. Since uranium obviously emits radioactive energy, it is only logical that the two elements that are in pitchblende (polonium and radium) would also emit radioactive energy because they are two of the elements uranium decays into.
-ryan34express
Good answer! Good use of deduction.
Re: Unit 1 Ch. 1 Reading Response pp. 8-9
August 26, 2009 by xrosein3
Alchemy did help greatly with the discovery of radiation.
-digger
Hmmm, could you elaborate on this one, digger? How so?
Unit 1 Ch. 1 Reading Response pp. 8-9
August 24, 2009 by xrosein3
Reply to the question(s) below. Make sure that each answer is thorough and complete. Please respond or comment about two other students posts. If you see something that is inaccurate or incomplete, please address it.
How has alchemy been beneficial to chemistry?
How can a rock like pitcheblend emit energy?
Considering Soddy's 1917 remark, what is more valuable than gold?
Questions for Powers
August 23, 2009 by xrosein3
If you have a question that you can't figure out, ask it here.
Whether it is a question about homework, or how to use this forum or whatever, post it here and I'll get an answer to you.
Re: Chapter 9 Reading Topic 1
February 18, 2009 by xrosein3
The reason a fire becomes bigger and releases more flame when you blow on it is because of the amount of oxygen being released from our breath. THe fire feeds off of oxygen and cannot burn without out it. For example i always used to think it was dumb to put out a fire with a blanket but by doing so the oxygen is restricted from the fire thus putting it out. The same thing goes for water and a fire extinguiser they just do the simple job of not allowing oxygen to the fire. That is why a flame burns more when a person blows on it.
-jordancolson
Good example of learning how something that used to seem silly now seems reasonable.
Re: Chapter 9 Reading Topic 1
February 18, 2009 by xrosein3
Smoldering coals are often blown on by campers to keep the flame alive. When you blow on the coals they get brighter and if you put some twigs in with them it will catch on fire. When a person exhales, they release about 14% oxygen. The new and abundant oxygen supply reacts with flame. Fire needs oxygen to burn so this is why coals become bright when blown on.
-nc16
Nice on the 14%. Where did you get the 14% statistic? Cite your source next time, for an even more impressive post!
Re: Chapter 9 Reading Topic 1
February 18, 2009 by xrosein3
The stoichiometry most relatively involved with the aforesaid statement is reaction stoichiometry which has to do with a mass relationship between reactants and products in a chemical reaction. When a person (notice the third person) blows on a smoldering fire he/she is giving off a fuel for it and that fuel is oxygen. the oxygen from his/her breath meets with the fire and a combustion reaction takes place. Oxygen is needed for the fire to keep burning. for example in an oxyacetylene torch two different tubes are applied. one with acetylene one with oxygen. acetylene itself can create a fire but it is not truly a torch until the oxygen is applied at which point the amount of oxygen applied depends on how ridiculously hot it becomes. because of the massive combustions reactions taking place.
-marcus banister (guest)
Great call on pointing out the mass relationship!
Re: Chapter 9 Reading Topic 1
February 17, 2009 by xrosein3
Nice, Nick. Thanks for the links. I've printed them out for potential future use.
Re: Chapter 9 Reading Topic 2
February 13, 2009 by xrosein3
I don't think that a result could exceed a theoretical yield. I think that maybe the way someone would get that answer would be if they did their measurements wrong in the first place. Also if their was to much of the reactants maybe there could be a higher percentage. Personally I don't believe that any yeild could be over 100%, 100% should be the highest it could go. So i believe that either a measurement was done wrong,or a math problem was done wrong to get the yeild over 100%. p.s powers... you never went over the forum thing in my class so i dont really know if this is the assignment so please go over it soon ha ha
-MiChElLe :) (guest)
Michelle, I'm so sorry. Your class will have an extension on the assignment, but you don't have to worry about it, because you are done. Good job! :-)
Re: Chapter 9 Reading Topic 1
February 13, 2009 by xrosein3
that actually makes a lot of sense, because i personally forgot that a fire burning would be giving off oxygen creating that combustion you were talking about
-MiChElLe :) (guest)
Just remember that fires produce carbon dioxide and burn oxygen.
Re: Chapter 9 Reading Topic 1
February 13, 2009 by xrosein3
Blowing on a smoldering fire helps the fire to get bigger. You can try waving air at the fire but it won't work as well as when you blow on the fire. The reason for that is because then you breath out, you breath out Carbon Dioxide, and when you breath out Carbon Dioxide, it reacts with the burning Oxygen that's in the fire. Here, a combusion reaction occurs. That is what happens when you blow on a smoldering fire.
-Jakob P. (guest)
Good thinking, but a slight modification is needed. Oxygen is burned in a fire, not carbon dioxide.
Chapter 9 Reading Topic 1
February 9, 2009 by xrosein3
You can reply to the question below for full credit of the pre-reading assignment. You need to write at least a five sentence paragraph. Please respond to other students if you think their answers are inaccurate or incomplete.
Explain the stoichiometery of blowing air on a smoldering campfire to keep the coals burning.
Chapter 9 Reading Topic 2
February 9, 2009 by xrosein3
You can reply to the question below for full credit of the pre-reading assignment. You need to write at least a five sentence paragraph. Please respond to other students if you think their answers are inaccurate or incomplete.
In the lab, you run an experiment that appears to have a percent yield of 115%. Propose reasons for this result. Can an actual yield ever exceed a theoretical yield? Explain your answer.
Chapter 9 Reading Topic 3
February 9, 2009 by xrosein3
You can reply to the question below for full credit of the pre-reading assignment. You need to write at least a five sentence paragraph. Please respond to other students if you think their answers are inaccurate or incomplete.
Very seldom are chemists able to achieve a 100% yield of a product from a chemical reaction. However, the yield of a reaction is usually important because of the expense involved in producing less product. For example, when magnesium metal is heated in a crucible at high temperatures, the product magnesium oxide, MgO, is formed. Based on your analysis of the reaction, describe some of the actions you would take to increase your percent yield.
Chapter 9 Reading Topic 4
February 9, 2009 by xrosein3
You can reply to the question below for full credit of the pre-reading assignment. You need to write at least a five sentence paragraph. Please respond to other students if you think their answers are inaccurate or incomplete.
The chemical equation is a good source of information concerning a reaction. Explain the relationship that exists between the actual yield of a reaction product and the chemical equation of the product.
Re: Lab help please?
February 9, 2009 by xrosein3
Sorry, Nick, would have gotten this sooner, but the e-mail section of Lefora is broken right now.
Chemicals undergo reactions to get to a more stable energy state. The electrons interact so that the atom can have an overall lower potential energy.
