studiot

One of the difficulties is do they mean Cp or Cv? I note the capital C which means the heat capacity for the whole body, not per kilgram, which would be denoted by a small c. Your thermodynamic analysis is not correct, allthough it leads to the correct equation. The State variable you require is the enthalpy, H. [math]\Delta _{400}^{300}H = \int_{T = 400}^{T = 300} {{C_p}} dT[/math] This integration does indeed give you q, the heat transferred by the first law since it does not include any work done. (Can you show this?) Using Cv on the otherhand would also include the work done as it refers to change of internal energy (U or E). In this integration the heat capacity is a function of temperature , so cannot be taken outside the integration as a constant.

Get a hold of this Cambridge University Press book Thermodynamics of the Earth and Planets Albero Patino Douce It contains a wealth of information about the contributions to the energy budget of not only the terrestrial type planets but others (gas giants) as well. In the case of the Earth a major contributor was the process known as differentiation. That is the migration of the heavier material towards the interior, eventually forming the core. Here is an extract with some facts and figures.

Correct. Guillem, Not sure why you are making such heavy weather of it. I said 'Never' surely indicates that there must be separate and distinct forces that only occur during a collision. Not before, not after, during. That is during the short period of time that the colliding objects are in physical contact. Because these forces only occur for short periods of time and are not constant during that time we do not normally work in terms of forces, but use the mechanics of momentum. On the other hand forces of attraction/repulsion act continuously over time (but vary over space as swansont has indicated) and act whether or not the objects are in physical contact. These forces have to be taken into account in the kinetic theory of ionic movement. There are potentially yet more complicated forces available. It is a matter of taste whether you consider the Kinetic Theory to cover only the simplest situation or extend it to Van der Waals, ions in solution, plasmas etc.

Can you check your question? In particular is the equation of state for the heat capacity in terms of temperature in kilojoules per degree K? The equation of state can't be correct as it stands since the RHS has units of (degrees)2 as stated. It may be an English language problem, but there is something wrong with the information as written. If it's any consolation you have your integration arithmetic correct, but that is not the issue.

The forces of collision are never of attraction or repulsion. What made you think they ever could be?

Well since [math]molarconcentration = \frac{{massconcentration}}{{molecularmass}}[/math] and the molecular mass is a constant the form of your graph is OK, but obviously for any result that needs to involve the the molar mass you will need that constant.

Since you haven't told us any of your sources, and I can't imagine why the CIA would be redacting sections of text on the subject, I am going to have to guess as to what you are on about. Assuming this is not a windup surely you know that many theories have a simple version and a more exact one? The 'kinetic theory' is no different, in fact there are a whole graded series of versions introducing more and more effects as they become closer to reality. So the simplest version assumes that the particles 1) Occupy zero volume or negilgable volume in relation to theri container volume. 2 Are only subject to forces of elastic collisions, both between the particles themselves and the particles and their container. These assumptions lead to the ideal gas laws. However neither are true in much of common experience so the gas laws are modified to take the actual volume of the particles into account and also again modified to account for interactions between particles. Van Der Waal's equation is one such. http://hyperphysics.phy-astr.gsu.edu/hbase/Kinetic/waal.html

Nice jaunty basic answer SJ. +1 But soap doesn't only act on the oils. Soap is also a surfactant. https://en.wikipedia.org/wiki/Surfactant This lowers the significant surface tension of water, allowing the water to better mix with other substances, dirt, microbes, oils, skin particles etc. Some soaps also change the pH of the water, making it more alkaline. Old fashioned 'lye' soap has this property. The change in pH has a mild bactericidal action. Scrubbing was not specifically mentioned and will enhance washing, with or without soap. But much washing is carried out without scrubbing and cleaning activity will still take place even without scrubbing.

This is a very strange question, since it implies you know a great deal more than you have said. How do you know its bonding structure and what do you mean by this? Are you trying for qualitative analysis rather than quantitaive analysis. That is do you just want to identify the constituent of something rather than its proportions? Do you have no clue as to the element or do you simply want to distinguish between one of several known alternatives? +1 to Sensei for picking two good, if expensive alternatives. Simpler methods might be to use an ignition tube test or a flame test. But check to make sure if the stuff you want to test is not hazardous.

I wouldn't recommend starting the study of properties of materials with asteroids. It may be current and sexy and even offer some novel insights, but is of limited use in the overall scheme of things. To discuss gravitational, magnetic and electric properties of matter, you need to know some details about them, so tell us what your level of knowledge is? Electric and magnetic fields can be readily shaped, this is much more difficult with gravitational fields. The early pioneers studied electric and magnetic fields confined to a particular region of space. The electric fields were confined by placing a slab of material between two confining plates making a condenser or capacitor. Confining magenetic fields made use of the fact that the field of an electic coil of is wholy contained within a toriodal winding. This is called a Rowland Ring after the discoverer J H Rowland. Rowland was able to distinguish three types of magnetic activity. Paramagnetism Diamagnetism Ferromagnetism The first two only appear in the presence of an existing magnetic field. The simple planetery model of the atom with electrons orbiting a nucleus is sufficient to explain this magnetic activity. Have you heard of the planetary model, due to Neils Bohr?

The sound produced by an internal combustion engine is largely conditioned by the exhaust system. The engine itself produces regular pressure pulses at a rate proprotional to the engine rpm, depending upon the number of cylinders or chambers (I once did some gas dynamics modelling on a rotary aero engine). The pulses provide a forcing excitation of a (sometimes very) complex pipe and chamber system which has several functions, one of which is to maintain constant back pressure on the engine. There are several proprietary programs dedicated to the analysis of the gas dynamics of exhaust systems. The exhaust system usually has a helmholtz resonator to extract energy and reduce the noise of the machine (or enhance it in the case of motor sport / motor cycle machines) Measurement of the noise accompanied by Fourier Analysis will result in a noise spectrum showing the engine input rpm and its harmonics, plus the effect of the resonators in the exhaust itself.

This BBC report is interesting as it is about a working test installation to inject atmospheric CO2 into volcanic basalt rock, permanently removing it from the atmosphere. http://www.bbc.co.uk/news/world-43789527

An HGV is a different classification and need not be articulated. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/211948/simplified-guide-to-lorry-types-and-weights.pdf Of course the term is made more difficult by the american pronunciation of the part word 'semi'.

In view of the subject of this thread I would be interested in hearing your experimental proceedure for comparing the respective tastes of saki and crap.

Hello Tristan and welcome. If you are serious with your enquiries/comments then you should have started your own threads about the subject not resurrected an old discredited one. I have reported this and if the mods choose to split this, I suggest you re-think carefully your wording and concentrate on one main issue per thread, as you have posed several (too many) questions for one thread.

We can best discuss your questions if you also consider mine. They are designed to help you understand/point you in the right direction. They are not designed to trip you up. Think about a tapering funnel. Now think about connecting it in line with a gas pipe so the gas flows through the funnel. If the gas enters at the narrow part and leaves via the wide part it will reduce in density as is passes through the funnel. But on average (to a first approximation) we consider the density constant at any cross section to the flow. So as the funnel widens the gas density reduces but is spread evenly at any cross section. This is easy to derive from the continuity equation. You can consider the field lines as a form of field density in the same way, so that it reduces as the field spreads out from the source, yet remain isopleths (the same strength) at any given distance (distance along the lines not a raidius). The next thing to think about is the question of where and what is the source. When the magnet is first introduced, the (say north pole end) end of the magnet is the beginning of the source. Even before a sliver of iron attaches itself to the end, a north pole is induced in the end of the sliver remote from the magnet. This north pole at the end of the sliver becomes the new 'source' and the sliver is then effectively part of the magnet. The connection is not perfect but good enough. Another sliver will attach at the end of the magnet, nearby but the two new areas of north pole will repel and so on. As the stack of slivers build outwards they adopt a 3D dendritic pattern (the hedgehog look), as shown in the videos, if free to do so. Swansont has mentioned that a paper surface provides some frictional restraint. It should also be noted that some machining process partially magentise the slivers so they may already have a preferential direction.

Personally I find the view best after 5 single malts.

First did you understand the explanation in the first page of this thread? One observation was that the simple demonstration refers to 2D section like your picture. But it is a 3D effect. So let us say that the white rectangles represent south seeking poles the what would you put into the space immediatedly adjacent to these south seeking poles above and below the plane of the paper?

Mass and energy generally follow the classsical conservation dictum "Matter can be neither created or destroyed" But money can be all to easily destroyed.

Interesting issue. Has anyone explored the possibility of particles (quantum) tunneling out of a black hole?

Not sure if you correctly understood my words or if I was not clear enough. I was trying to avoid discussion of 'infinity' since every Zeno paradox mixes an abstract infinity with a concrete situation. (continuing the terminology I already introduced). Even in the Zeno paradox (Ken, you do understand I don't find this 'paradox' without explanation?) the abstract infinity is introduced by the word 'never'. The ancient Greeks acknowledged two kinds of infinity - They called these actual infinity and potential https://en.wikipedia.org/wiki/Actual_infinity So for instance if they had decimal numbers they could have made the distinction between a non terminating decimal of finite magnitude and the totality of all numbers. The infinities introduced by Zeno are all non terminating processes, usually the indefinite division of a finite space or time. Some of the (more complicated) paradoxes transfer the result of the indefinite division from one parameter to another to try to establish a fallacy. For instance "The arrow will never reach its target or the runner finish the race because there is always some remaining distance to go which take a finite amount of time (however small) to transit so the motion will never terminate." This is still wrong thinking (take him away ), but one has to be careful to observe where the slip occurs.

I don't mind sensible questions. Discharge is the correct term for the flow rate of water - clean or dirty - Discharge is measured in litres per second or cubic metres per second. That is it is the volumetric flow rate. (by volume) So the cooling water from the power station is water they have finished with ie it is waste in this process. But what you haven't told me is why you posted this in inorganic chemistry. Nor have you said what subject this model if for. Much of the dirty water we generate is contaminated (made dirty) by organic material. Nor have you said anything about the model aspect. Did you understand my explanation of why I suggested a power station? You can surely google questions like 'average amount of water used in a power station?' and find some power stations on some river and google say ' river flow of river Trent'? Then your model could be a simple calculation mixing X amount of cooling water with Y amount of river water.

Thanks for this Orion, but the whole point of having a Tex editor is to avoid personal coding. (MathTypes also produces MathML.) Why keep an alligator and bite yourself?

Well this is a great deal better as it sets the scene. You have now found out that the subject is too huge to fit it all into a small presentation. So you need to narrow it down to one area. You choose. You also say modelling. A model must predict something. That is what it is for. So how about the environmental effect of the waste cooling water from a power station, (not neccessarily nuclear)? You could find out how much waste water is produced. Then findout how much water flows down some river or rivers. Then you model could show how much thermal pollution discharging the wastewater to the river produces and predict the temperature rise of the river water in the locality of the power station. You could then discuss whether this is important. Your model could also say what is the maximum discharge for the health of given fish or other species in the river.

A presentation? To whom? For what purpose? Is this homework? If you don't know and can't be bothered to look them up or at least give us a clue here, why should anyone else bother? What do you mean by wastewater? The effluent from an industrial plant say the washing out water from a concrete works, or the wastewater from a paper mill or wool mill? Or do you mean sewage? Or do you mean so called grey water? And what do you want to treat it for? What are you going to do with the treated water? Then one might ask what aspect are you interested in during a short presentation about modelling the treatment? The (Bio)Chemistry? The Fluid Dynamics? The Structural and Mechanical Engineering of the plant? The ecological and environmental aspects? The classic textbook on Nos 2 and 3 is Water and Wastewater Engineering Professor Carey Dublin University