Thermodynamics and Statistical Mechanics

Mechanics deals with the motion of objects and the forces acting on them, while thermodynamics focuses on the relationships between heat, work, and energy transfer. Mechanics is concerned with the behavior of macroscopic objects, while thermodynamics looks at the macroscopic properties of systems in equilibrium.

High heat can denature enzymes, disrupting their structure and functional shape. This can render the enzymes inactive or reduce their efficiency in catalyzing biochemical reactions. Additionally, prolonged exposure to high heat can lead to irreversible damage to enzymes.

The SI unit for power, thermal or mechanical, is the watt, W.

1 W = 1 J/s (joule/second).

An equation of state is one that relates "state" variables. A state variable is one that only depends on the current state of a system, not how you got there. Examples of state variables include (but are not limited to); Temperature, Pressure, Internal energy (or specific internal energy), density (or its reciprocal, specific volume), enthalpy, Gibbs free energy, entropy, and fugacity. These are in contrast to path variable such as Work and Heat. To calculate the change in a state variable, you only need to know the beginning and ending states. Because it is not path dependent, we often do the calculations in pieces along a hypothetical path were we know how to calculate each change and then add them up. The path we calculate does not need to be the actual path taken. Contrast this with calculating the work done along a path - where the path is everything.

An example would be calculating a change in elevation for a car. You could calculate it by taking a hypothetical path where you drop it from its current elevation to sea level and then raise it from sea level back to its final elevation. Contrast that with figuring out how much gasoline it would take to drive it from a farm in the hills down to the coast and then back up into the mountains. The work for that path would be different from taking a road straight from the farm up into the mountains. The change in elevation from start to finish would still be the same though - elevation is a state function and calculations of elevation are state functions.

Some of the commonly used equations of state deal specifically with the relationship between the Pressure, Temperature, and Volume (or specific volume) of a system - especially gases. Examples include:

Ideal Gas Law

PV = nRT

Van derWaals

(P + n2a/V2)(V - nb) = nRT

Redlich-Kwong

P = RT/(Vm - b) - a/[√T · Vm(Vm + b)] where Vm = V/n, the molar volume

Others include the Soave modification to Redlich-Kwong, Wilson, and Peng-Robinson.

Not all of these equations work well under all conditions. The Ideal Gas Law fails as systems become cold and dense. The Wilson Equation fails to predict the existence of liquid/liquid immiscibility (like oil and water). None of the above equations of state describe solids - that requires still other equations of state.

Sink temp, or sink temperature, refers to the temperature of a heat sink, which is a device that helps transfer heat away from a component or system to prevent overheating. Maintaining a lower sink temperature is crucial for efficient heat dissipation and proper functioning of electronic devices.

The Second Law of Thermodynamics states that a system with no energy input and no losses will tend towards a zero energy state. This is essentially the entropy of any energy exchange. Thus, you require a constant input of energy to maintain any system.

When Tf Tr equals Tr Tw, it improves the accuracy of the experiment because it allows for an efficient transfer of heat energy between the sample (Tf), reference (Tr), and the surroundings (Tw). This ensures that the temperature readings are stable and reliable, eliminating any potential errors or fluctuations in the measurements. This consistency in temperature conditions helps to enhance the precision and reliability of the experimental results.

Cooling rate refers to the speed at which a material loses heat during the cooling process. It can be measured by monitoring the temperature of the material over time using a thermometer or sensors. The cooling rate is influenced by factors such as the material's thermal conductivity, its surface area exposed to the surrounding environment, and the temperature difference between the material and its surroundings.

When a steadily flowing gas flows from a larger diameter pipe to a smaller diameter pipe the speed of gas is decreased and pressure become increased and the spacing between the streamlines less and the streamlines come very close to each other.

In adsorption, Gibbs free energy decreases because the adsorbate molecules are attracted to the surface of the adsorbent, reducing the overall energy of the system. This leads to a more stable configuration with a lower free energy. The decrease in Gibbs free energy indicates that the adsorption process is spontaneous at a given temperature and pressure.

Paraffin generally cools slower than water due to its lower thermal conductivity. This means that it takes longer for heat to transfer through paraffin, resulting in a slower rate of cooling compared to water.

This involves both the first and second laws of thermodynamics.

According to the first law, the energy you expend must come from somewhere. You have to take in that energy in the form of the chemical energy contained in the food before you can expend energy to move yourself around, grow, heal, breath, etc.

According to the second law, that energy will not flow into you spontaneously. You must expend energy to draw that energy into your body for use, in other words, you have to eat.

Microscopic viewpoint in thermodynamics focuses on individual molecules and their interactions, while macroscopic viewpoint looks at bulk properties of a system, such as temperature and pressure. These viewpoints help to describe and analyze the behavior of systems at different scales.

The temperature must heighten for ice to melt. The melting point of ice/water is about 0 degrees Celsius.

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Suppose we are at 1 atmosphere and we want to melt an ice cube (of pure water)

that is at -5oC. We give heat to the ice cube (hypothetically at very slow rate so we warm the ice cube in a homogeneous fashion). The temperature of the ice cube will rise to 00C before it starts to melt. During the melting process the heat given to the ice is invested in braking the intermolecular bonds. This is called the latent heat of fusion or

fusion enthalpy. Not until the ice completely melts, the temperature will start going up again.

250g of water at 10C needs to lose 1 cal/g/C or 2500 calories to drop temperature to zero.

The latent heat of fusion of water is 80 calories per gram at 0C so, the water needs to lose 20,000 calories to turn to ice at 0C

Finally, the ice needs to lose 0.316 cal/g/C or 790 calories to drop to -10C

The total heat released is then 2500 + 20,000 + 790 = 23,290 calories

The change in internal energy is the sum of heat added to the system and work done by the system on the surroundings. So, the change in internal energy is 2.500J (heat absorbed) - 7.655J (work done), resulting in a change of -5.155J.

Thermodynamics of diffusion involves the study of how energy changes affect the movement of particles from regions of high concentration to low concentration. It examines the relationship between temperature, pressure, and concentration gradients on the rate and direction of diffusion. This field helps in predicting and understanding diffusion processes in various systems.

One of the consequences of the 2nd law is that it is impossible for a power plant to achieve 100% efficiency. In fact the maximum efficiency is limited by the temperature of the boiler and temperature of the condenser for power plants powered by heat (like coal, gas fired, and nuclear).

1st. Principle-- If two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other.

2nd. Principle-- Heat energy and mechanical work are mutually convertible.

3rd.-- It is impossible to construct a mechanical device ( engine) whose sole purpose is to convert all of the heat energy supply to it into equal amount of work.

4th.-- The entropy of a pure crystalline substance at absolute zero temperature is zero

A steam trap is used to remove condensate (liquid) that forms in steam systems. If condensate is not removed, it can cause water hammer, reduce heat transfer efficiency, and affect the overall performance of the system. The steam trap helps prevent damage to equipment and ensures that only steam flows through the system.

Kinetic energy is the energy of motion, KE=mv2/2.

Thermal energy is different from kinetic energy.

Thermal energy is associated with the temperature of a body, the heat gained by increasing the temperature. That heat gives molecules more kinetic energy and more potential energy and may also give molecules more more electronic energy.

The work of Sadi Carnot, a French engineer, on the efficiency of heat engines in the early 19th century led to the formulation of the second law of thermodynamics. Carnot's insights on the limitations of heat engine efficiency laid the foundation for the development of the second law, which eventually became a fundamental principle in thermodynamics.

Direct heating can be thermodynamically wasteful because a significant amount of heat is lost to the surroundings during the heating process. This leads to lower efficiency in converting energy to heat, as the heat is not efficiently retained or transferred to the substance being heated. This wastage results in higher energy consumption and costs.

Specific heat is usually defined as the amount of energy that must be added to change the temperature. Another way to define it is the ratio between the amount of energy added and the change in temperature E/m·T(with units like joules/gram·°C) When water is at the saturation point and energy is added to it, instead of increasing in temperature, the water changes phase from liquid to gas. If you put the numbers back into the definition you get something like:

1 joule added to 1 gram of water yields a change of 0 °C so

Cp = 1/1∙0 = ∞.