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Thermodynamics and Statistical Mechanics
Thermodynamics is the study of energy conversion between heat and mechanical work which leads to the macroscopic properties such as temperature, volume, and pressure. Statistical mechanics is the application of probability theory to study the thermodynamic behavior of systems of a large number of particles.
1,125 Questions
Is thermodynamics a law or theory?
Thermodynamics is both a law and a theory. It has a set of well-established laws, such as the first and second laws of thermodynamics, which describe the behavior of energy in systems. Additionally, the principles and concepts underlying thermodynamics are formulated into a theory to explain and predict the behavior of physical systems.
Could you use a lump of metal to warm your bed instead of a hot water bottle?
Of course you could. The old bed warmers that they put hot coals in were made of metal
It would have some drawbacks however:
- Compared to metals, the temperature of the water in the hot water bottle is limited to a comparatively safe range by the physical properties of water, it will boil off at 212 °F./100 °C. On the other hand you can get metals white hot- enough to burn right through the material of your bed - and they will still be solid.
- Water has a higher heat capacity than metals per unit mass and per unit volume so it can supply more heat without having to start out as hot as the metal would have to in order to supply the same amount of heat.
- Because it has a higher heat capacity it would also take less water to warm the bed than metal.
- An empty hot water bottle is easier to store than a chunk of metal - and a lot cheaper.
The change in internal energy can be calculated as the sum of the work done and heat added to the system. The work done is already in Joules, so we need to convert the heat added from calories to Joules: 200 cal = 837.4 J. Thus, the change in internal energy is 1200 J + 837.4 J = 2037.4 J.
Suggestions for percent error R gas constant?
To calculate the percent error for the gas constant (R), you would compare the experimental value to the accepted value. Subtract the accepted value from the experimental value, divide by the accepted value, and then multiply by 100 to get the percent error. This will help you determine the accuracy of your experimental measurement of the gas constant.
If the particles are electrically neutral the state of matter is a gas.
If the particles ore ionized - a "soup" of electrons and positively charged ions, it is a plasma.
Could you review the laws of thermodynamics?
- Zeroth law of thermodynamics: If two systems are in thermal equilibrium with a third system, they must be in thermal equilibrium with each other. This law helps define the notion of temperature.
- First law of thermodynamics: Heat is a form of energy.Because energy is conserved, the internal energy of a system changes as heat flows in or out of it. Equivalently, perpetual motion machines of the first kind are impossible.
- Second law of thermodynamics: The entropy of any closed system not in thermal equilibrium almost always increases.Closed systems spontaneously evolve towards thermal equilibrium -- the state of maximum entropy of the system -- in a process known as "thermalization". Equivalently, perpetual motion machines of the second kind are impossible.
- Third law of thermodynamics: The entropy of a system approaches a constant value as the temperature approaches zero.The entropy of a system at absolute zero is typically zero, and in all cases is determined only by the number of different ground states it has
Using the phase diagram for CO2 what phase is carbon dioxide in at -20C and 1 ATM pressure?
The triple point of Carbon Dioxide is 216.55 K (−56.60 °C) and 517 kPa (5.10 atm). Since that puts the pressure (1 atm) below the triple point pressure (5.1 atm) we are only concerned with the where the solid/vapor equilibrium line falls relative to the temperature. At 1 atm, the sublimation temperature of Carbon Dioxide is -78.5 °C - considerably below -20 °C so that puts the Carbon Dioxide firmly in the vapor region of the phase diagram.
A phase diagram identifies the state of matter of a substance for specific combinations of?
A phase diagram identifies the state of matter of a substance for specific combinations of temperature and pressure. It shows the boundaries between different states (solid, liquid, gas) and regions where two phases coexist. The diagram helps understand how a substance behaves under different conditions.
In thermodynamics what is meant by you can't get out of the game?
You can't get ahead (1st law - conservation of energy - you can't get more energy out than you put in)
You can't even break even (2nd law - 100% efficiency is not possible - some energy will always be lost as heat to the surroundings, thus increasing the overall entropy of the universe)
You can't get out of the game (no real process is reversible)
The temperature of the hot object will be reduced unless it is undergoing a phase change - in which case it may remain at the same temperature until the phase change is complete - and then drop in temperature if the cold object has not reached the same temperature.
Which law states absolute zero cannot be reached?
This would be a consequence of the 2nd law and the "zeroeth" law. Heat always flows from the warmer object to the colder one (2nd law), so to cool something down to absolute zero, you would have to have something colder than absolute zero to absorb the heat coming out. The zeroeth law, however, defines absolute zero as a ground state where energy has been reduced to its absolute minimum - thus you cannot go below absolute zero and thus there cannot be something to absorb the energy to take an object to system down to absolute zero.
Is conservation of energy involved in the second law of thermodynamics?
It is assumed as part of the second law, but the second law is really all about what happens to the energy as it changes form. If energy were not conserved (1st Law), then it might be possible to violate the second law by magically creating some energy out of nowhere to allow the work coming out of a system to be equal to the energy input even when some is lost to heat.
What is the speed of air at 27 degree Celsius?
At 27 degrees Celsius, the speed of air molecules would depend on various factors such as pressure and density. However, the average speed of air molecules at room temperature (~27 degrees Celsius) is typically around 460 meters per second.
Does the cubical expansivity of a liquid depend on its original volume?
No. The expansivity is on a per unit basis just like the specific heat or density is.
Can you use thermodynamic in a sentence?
The laws of thermodynamics govern energy transfer and transformation within a system, providing a framework to understand the behavior of matter and energy under different conditions.
What is the fundamental interval on the thermodynamics scale?
The fundamental interval on the thermodynamic scale is the Kelvin scale, where the interval between each degree is the same size. This scale begins at absolute zero and is used to measure temperature in thermodynamics.
What is matter and energy second law of thermodynamics?
The second law of thermodynamics states essentially that it is impossible for heat to flow from a cooler body to a hotter one, without the performance of work by an external agency. I'm not sure how this relates to your wording of 'matter and energy'.
In the science of thermodynamics the property of randomness is also referred to as?
Entropy. It represents the measure of disorder and randomness within a system. In thermodynamics, entropy tends to increase over time in isolated systems, reflecting the tendency of systems to move towards equilibrium.
It is never possible to totally convert heat energy into useful work true or false?
True. According to the second law of thermodynamics, it is impossible to convert all heat energy into useful work, as some energy will always be lost to heat transfer or other inefficiencies in the conversion process. This principle is known as the Carnot efficiency limit.
In thermodynamics a closed system is a system where?
In thermodynamics, a closed system is a system in which no mass can enter or leave the system, but energy can be transferred in the form of heat or work. This means that the total mass of the system remains constant over time, but energy can be exchanged with the surroundings.
How does the second law of thermodynamics predict the behavior of gasses?
The Second Law predicts that a reaction or process occurs if the entropy increases. Informally, "disorder" will increase; though this is not a very exact definition. Some things where this applies to in gases include:* If you bring two gases together, they will mix.
* Pressures will tend to be equalized.
* Temperatures will tend to be equalized.
When snow melts what happens to temp?
Melting is a phase change. Typically what happens is that the snow absorbs heat until it has warmed to the melting point. As it continues to absorb heat, it undergoes an isothermal (the temperature doesn't change) phase change (melts). Once it has melted, it may continue to warm up above the melting point temperature. In practice different parts of the snow will be at different temperatures. The snow at the surface will be absorbing the heat and melting. As it melts, the water from the melted snow runs down into the unmelted snow where it supplies heat to that snow to start warming it up.
Type of thermodynamic properties?
Thermodynamic properties are specific volume, density, pressure, and temperature. Other properties are constant pressure, constant volume specific heats, Gibbs free energy, specific internal energy and enthalpy, and entropy.
How does energy efficiency relate to the first and second law of thermodynamics?
By the first law of thermodynamics, energy is conserved - i.e. the sum of the useful work and the energy lost to heat will equal the energy you started with.
The second law states that you will never get 100% energy efficiency.
