| Subject | Date Asked | Expert |
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| Open Window cooling | 11/11/2009 | Kevin |
Q: I have been wondering; how can one measure or use a formula to find the cooling done in a room by an ...
A: There are several factors which have to go into the model. One is the difference in temperature ...
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| Thermoelectric Generators? | 11/8/2009 | Kevin |
Q: If I'm correct thermoelectric generators are used to convert heat into electricity. Why don't they ...
A: These devices are very inefficient (5-8%) and can only usefully be considered with waste heat. They ...
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| LPG Vs Petrol Vs Ethanol | 11/2/2009 | Kevin |
Q: I am currently doing a chemistry assignment on the validity of using LPG or pure Ethanol (not a mix ...
A: This is too long and involved for me to do so I will supply some brief answers/suggestions. Q1. You ...
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| Atomic Structure | 10/26/2009 | Kevin |
Q: I am an eighth grade student and we have been asked to interview a chemist. I would appreciate it ...
A: Q1 You read the label on the jars! But if there is no label there are a series of tests that you do ...
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| 8th grade interview | 10/26/2009 | Kevin |
Q: Hey in am eighth grader and I have been asked to interveiw an expert so I was wandering if I could ...
A: Q1. Yes at one point in my career I was responsible for making a range of phenol derivatives as pure ...
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| thermodynamic arrow of time | 10/14/2009 | Richard J. Raridon |
Q: As time passes, physicists say the energy in the universe becomes unusable or disorganized. I don't ...
A: Entropy is a measure of disorder. Although a few atoms might become more organized, indicating a ...
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| how salt effects boiling water | 10/11/2009 | Kevin |
Q: I've heard several times that salt makes water boil faster and that is why people add it to the food ...
A: Adding salt to water allows the salt to be spread evenly throughout the water. Water has to be ...
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| physics | 10/10/2009 | Kevin |
Q: The outside diameter of a wheel is 1m. An iron tire for this wheel has an inside diameter of .992m ...
A: You need to treat the hoop as a straight piece of iron. The piece is 0.992m and needs to be 1.001m. ...
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| Thermodynamics | 10/8/2009 | Kevin |
Q: Why does residual Gibbs energy have a link to experiment while Gibbs energy does not? In other ...
A: This is a difficult and profound question and lies at the root of why chemical reactions occur at ...
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| Printer Cartridge | 10/5/2009 | Kevin |
Q: I watched a show called "How They do It" on the Discovery Channel. This is a Canadian science ...
A: This is a popular science show not a university lecture so a lot of "poetic license" is in use to ...
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| chem question | 10/4/2009 | Kevin |
Q: Hey I've been stuck on this question for over 2 hours from an old test of one of my professors. ...
A: You need to know how many moles of each (H2S and SO2) are present to do this is easy with the H2S as ...
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| dyne | 10/2/2009 | Kevin |
Q: i want to ask what is the history of a dyne as a unit? i mean who invented it and how did it come ...
A: We now work in the KMS or SI system, kilogram, meter, second. In other words all are units are based ...
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| thermodynamics | 10/2/2009 | Kevin |
Q: i am studynig metallurgy engineering and have 2 questions. first i want to know what is the ...
A: Thermodynamics is that subset of Physical chemistry which concerns itself with heat. As opposed to ...
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| thermodynamics | 9/25/2009 | Kevin |
Q: I understand that the combustion of a hydrocarbon releases thermal energy and visible light energy ...
A: The light emitted from burning a hydrocarbon is a function of the way in which the reaction is ...
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| Steel expantion | 9/24/2009 | Kevin |
Q: How do I detriment the growth of oil field casing when heat (steam) is apply. Casing is ran and ...
A: No stretching the pipe will not work. Metal expands and contracts as it is heated and cooled. This ...
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| Steel expantion | 9/23/2009 | Kevin |
Q: How do I detriment the growth of oil field casing when heat (steam) is apply. Casing is ran and ...
A: The steel will grow by 12 X 10^-6 of its original length (1.000012 times) for every 1°C temperature ...
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| Radium Clock | 9/17/2009 | Kevin |
Q: Q1. Can a small amount of Radium be used to charge an electroscope? Q2. If so, can you use the ...
A: The basis of the whole thing is radioactive decay. The unstable radium nucleus wants to split into ...
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| Liquid Nitrogen | 9/17/2009 | Kevin |
Q: What technology do scientists use to create liquid nitrogen?
A: It is just basic engineering using compressors, pumps and valves. Basically they take air and ...
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| Radium Clock | 9/16/2009 | Kevin |
Q: Q1. Can a small amount of Radium be used to charge an electroscope? Q2. If so, can you use the ...
A: A1. Yes I have done this experiment when I was at school and radium will cause an electroscope to ...
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| Wood flame vs. C4N2-O3 flame -- which emits more radiant heat? | 9/14/2009 | Kevin |
Q: A dicyanoacetylene-ozone [C4N2-O3] flame reaches a temperature of 5516 K. This causes it to emit EM ...
A: "Since IR generates more heat on human skin than UV of the same intensity" This is not true. UV is ...
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| Do yellow flames emit more infrared than blue flames? | 9/12/2009 | Kevin |
Q: Does a yellow bituminous coal flame give off more infrared radiant heat than a blue methane flame? ...
A: The amount of radiation of any specific wavelength (UV, Visible, IR) given out by a flame is ...
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| thermodynamics | 9/8/2009 | Kevin |
Q: i have problem in understanding that "in a cyclic process the internal energy of a system remains ...
A: If you take a tank of gas (A) compress it to half its volume heat it to 100°C expand it to its ...
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| please help | 9/7/2009 | Richard J. Raridon |
Q: The weight of the block in the drawing is 93.7 N. The coefficient of static friction between the ...
A: F = ma = T-0.85mgcos(21) -mgsin(21) T = 271(0.8) +0.85(271)(9.8)cos(21) +271(9.8)sin(21) = 3276N ...
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| thermodynamics | 9/3/2009 | Richard J. Raridon |
Q: please tell me the difference between heat capacity,specific heat and molar specific heat in a very ...
A: Basically, heat capacity and specific heat are the same thing, the amount of heat required to raise ...
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| Specific heat capacity | 8/30/2009 | Kevin |
Q: hey i was just wondering what is the specific heat capacity of ethanol, methanol and propan-1-ol? ...
A: The specific heats are Methaanol 0.57 Ethanol 0.54 Propan-1-ol 0.52 cal/g K. The normal procedure ...
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| bonding in thermochemistry | 8/27/2009 | Kevin |
Q: hey kevin i'm doing some work on thermochemistry in the form of calorimetery. i'm doing the three ...
A: Bond energies are published in many documents. They can be used to estimated the heat of reaction ...
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| dangarous radiation | 8/25/2009 | Kevin |
Q: could you help me please I want to ask you some iq about dangarous radiation ...
A: All radiation is part of the electro-magnetic radiation spectrum. At one end are low energy radio ...
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| Water evaporation mass and volume | 8/24/2009 | Kevin |
Q: I am trying to understand how water evaporates. My current understanding is that water molecules ...
A: A GAS FILLS ALL SPACE EQUALLY (OVER TIME). Why? Is it because the molecules are pushing away from ...
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| Loading road vehicles in a refinery. | 8/24/2009 | Kevin |
Q: Working on a bitumen plant, we load road vehicles(one at a time or several),from bitumen storage ...
A: Without looking at your system directly I can only guess. If you are pumping bitumen out of a ...
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| thermodynamics | 8/24/2009 | Kevin |
Q: please tell me why we do not use the symbol of degree when we refer to kelvin scale.for example why ...
A: The old temperatures (°F, °C etc) were based on the fixed melting and boiling of various pure ...
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| Water evaporation mass and volume | 8/24/2009 | Kevin |
Q: I am trying to understand how water evaporates. My current understanding is that water molecules ...
A: ---------- FOLLOW-UP ----------Hi Kevin Thank you for your answer. You are getting there but, I am ...
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| Water evaporation mass and volume | 8/24/2009 | Kevin |
Q: I am trying to understand how water evaporates. My current understanding is that water molecules ...
A: Your basic idea of molecules of water "bouncing" around is sound if unsophisticated. More accurately ...
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| comparing different energies | 8/20/2009 | Kevin |
Q: Can you tell me how one goes about answering thisHow big does a compressed air tank have to be so ...
A: If you assume that the engine is 2.0 l capacity in both cases and that it takes 1.0 l of air to ...
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| Cooling hot equipment in space? | 8/18/2009 | Kevin |
Q: In short, my question is this: if you have something hot in space (in a spacecraft for instance), ...
A: The answer is that space is very cold 3K or -270°C. Once in true space, away from our Sun, it is ...
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| Preheating Steel | 8/17/2009 | Richard J. Raridon |
Q: We originally had to preheat 4" thick steel to 225 degrees prior to welding and now we have to ...
A: I assume you're talking degrees C. So you're heating from 25C to 350C instead of 25C to 225C. That ...
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| physics of cold water | 7/25/2009 | Kevin |
Q: I wanted to know why ice cubes would have a spike of ice in them near the middle, at about a 20 ...
A: This is thought to be caused by the water in the center freezing more slowly than the water at the ...
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| a bottle of steam | 7/21/2009 | Kevin |
Q: My name is Nicolae Gari, and I would like to thank you for your previous answers several months ago. ...
A: Well here goes, water boils when its vapour pressure equals the pressure of the gas above it. On ...
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| a bottle of steam | 7/20/2009 | Kevin |
Q: My name is Nicolae Gari, and I would like to thank you for your previous answers several months ago. ...
A: In deep space if we open a bottle of water the water will start to boil. The boiling will be ...
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| Heat transfer rate | 7/20/2009 | Kevin |
Q: Kevin, I asked this question earlier today, but was mistaken as a home work question. It is ...
A: You are in the specialist area of heat transfer. I cannot go into detail here as the limited fonts ...
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| a bottle of steam | 7/20/2009 | Kevin |
Q: My name is Nicolae Gari, and I would like to thank you for your previous answers several months ago. ...
A: It works like this. Water always has some of its molecules as a gas above it (as steam or vapour). ...
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