# Tag Info

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No. In fact, water has a negative coefficient of expansion from $0 C$ to $4 C$ .

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It is not true in general that liquids expand linearly with the temperature but it might be true for a particular liquid and a particular temperature scale. Let us say you have mercury. You put that Mercury inside your fridge and after some time you measure its volume and define this Mercury is at $0\, \mathrm{X}$, where $\mathrm{X}$ is the scale you are ...

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I agree with you that most books do not follow a logical path when defining thermodynamics terms. Even great books such as Fermi's and Pauli's. The first thing you need to define is the concept of thermodynamic variables. Thermodynamic variables are macroscopic quantities whose values depend only on the current state of thermodynamic equilibrium of ...

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The critical pressure is given by $$P_c=\frac{a}{27b^2},$$ while the critical temperature is $$T_c=\frac{8a}{27bR}=\frac{8bP_c}{R}.$$ The parameter $b$ is related to to the effective volume occupied by the molecules, $$b=4N_0V_0,$$ where $V_0$ is the volume of the molecule and $N_0$ is the Avogadro number. So at least theoretically you can chose $P_c=1\, \... 3 Whether an answer exists depends on your definition of "near" compared to STP. There are a few fluids that have their critical point at a temperature close to STP, but higher pressure. For example, (see http://www.engineeringtoolbox.com/critical-point-d_997.html) material Tc(K) Pc(atm) acetylene 309.5 61.6 ethylene 283.1 50.5 ethane ... 1 I tried to look around but I couldn't find anything. It does seem like supercritical$\mathrm{CO_2}$is very popular in applications because the critical temperature is just a little over$30^{\circ}\mathrm{C}$, but it still requires 73 atmospheres of pressure. An interesting thing mentioned on the Wiki page is that Venus may have had supercritical$\mathrm{...

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Volume is not a meaningful measure of quantity, for the reason you hint at in your question. You can say how many moles (or grams) of water you drank - more useful if you want to know about the impact on your body chemistry. This is related to my answer about scales measuring in grams rather than Newtons. Can you see how?

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When ice is heated from 0 to 4 degrees C, it actually contracts. The water molecules get closer together and the water occupies less volume. However, above 4 degrees C water expands(i.e. in your case). This is explained by Charles's law but any way this change in volume is not very drastic. This calculator might be helpful

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$1$ litre of water will remain almost $1$ litre as long as it is in the liquid state, no matter what the temperature is. The following formula gives you an order of magnitude estimate of the expansion: $$\Delta V=V_0\ \Delta T \ \beta$$ where $\beta$ is the coefficient of thermal expansion and $V_0$ is the initial volume. For water, $\beta \approx 10^{-... 0 I will give contra example for some of the comments: You can blow with mouth wide open very hard and then the speed of air is high but it is still worm. Also you can blow with lips pursed very gently and the air speed is slow, but still you feel it is colder … so the right answer is : air comes out cold, because it expands coming out of small opening. 0 The definition of an empirical temperature is basically what the Zeroth Law of Thermodynamics does. Let us suppose we do not have any prior knowledge about temperature. What we do know is that if we put two bodies in contact with each other they may change some thermodynamic properties -volume, for instance - of one another. When such a thing happens we say ... 6 The temperature appearing the the Clausius inequality is definitely the temperature of the "boundary interface (with the surroundings)", or simply the temperature of the sources. One of the best places I have seen this discussion is in Fermi's book, chapter 5, section 11. He is explicit about it. To see this you have to recapitulate the steps in obtaining ... 2 So, scientists were surprised when they found that Mercury has a molten core. Since small planets (like Mercury) cool rapidly, the core should've frozen a while ago. In a nutshell, though, whether or not the core stays molten over time depends on the composition of the core...as this website says, Maintaining a molten core over billions of years ... 1 Advantages Very accurate ( In fact its accuracy allows it to be utilised to calibrate other thermometers) Wide Range Independent of gas used Disadvantages Large and bulky(inconvenient to carry and handke) Slow to Respond (due high heat capacity) Expensive to manufacture and keep I'm not sure about its use in any specific industries. 3 You already have the answer when you write $$\frac{\Delta h}{h} = (\beta -2\alpha)\Delta T$$ What you do after that is unnecessary and does not make sense. You have already said that the height of the tube is irrelevant, so the height of the liquid "relative to the tube" is meaningless. If initially the liquid fills the tube completely and you want to ... 1 Actually the formula given in your question describes the thermal efficiency$Nth$of a device , usually a heat engine that transforms thermal energy into mechanical energy and it's always:$Nth<1$. On the other hand$COP$or coefficient of performance is the ratio$Q/W$of the device called heat pump, where$Q$is the heat removed from the cold ... 0 According to this hyperphysics article on heat pumps, the COP is given by $$\rm{COP}=\frac{T_H}{T_H-T_C}$$ which is not quite the equation you gave (actually it is the inverse). Once could ask the question: if I change either the high or low temperature by 1 degree, which of these will change the value of COP most? If you lower$T_C$by 1°C, the ... 0 If you look closely at the working of the heat pump , it follows reverse Carnot cycle. As you know that Carnot cycle is explained from piston and its intraction with source and sink slabs. When piston is placed on sink stand and expanded isothermally the heat is transferred from sink to piston, then the piston is adiabatically compressed so that its ... 19 Ice can be denser than water for certain values of$P,T$. Look at these two pictures taken from here: The darker areas in the second picture denotes areas of greater density. So you can clearly see that when pressure is increased, ice becomes denser than water along the coexistence line. For example at$T=400\$ K ice VII is clearly denser than water ...

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P-V work is not the only kind of work that can be done on the contents of your system. In the case of your fan example, the fan is doing work on the gas within the container by exerting force on it through a displacement (of the fan blade). The kinetic energy imparted to the gas by the fan is then converted to internal energy by viscous dissipation (a ...

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If a body (substance) has zero kinetic energy then we should suppose that it is a perfect crystal at absolute zero and all motion is in the vibrational ground state if it is a molecule. If an atomic solid then only zero point motion in the lattice. So yes it has a temperature. The potential energy is that within and between the molecules or atoms. In your ...

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