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# Heat & Thermodynamics

Thermodynamics is a branch of natural science concerned with heat and its relation to energy and work. It defines macroscopic variables, such as temperature, internal energy, entropy and pressure, which characterize materials and radiation. It explains how they are related and by what laws they change with time. Thermodynamics describes the average behavior of very large numbers of microscopic constituents. Its laws are derived from statistical mechanics.

Thermodynamics can be applied to a wide variety of topics in science and engineering such as engines, phase transitions, chemical reactions, transport phenomena and black holes. The results of thermodynamic calculations are vital for many fields including, chemistry, chemical engineering, aerospace engineering, mechanical engineering, cell biology, bio-medical engineering and material science.

Thermodynamics was developed out of the desire to increase the efficiency of early steam engines. In particularly, the French physicist Nicolas Leonard Sadi Carnot in 1824 who believed that the efficiency of heat engines was the key that could help France win the Napoleonic Wars. However, the Irish born British physicist Lord Kelvin was the first to formulate a concise definition of thermodynamics in 1854.

Initially, thermodynamics of heat engines were concerned mainly with the thermal properties of their working material, such as steam. This study was then linked to the study of energy transfers in chemical processes/ Chemical thermodynamics studies the role of entropy in chemical reactions. Statistical thermodynamics gave explanations of macroscopic thermodynamics by statistical predictions of the collective motion of particles based on the mechanics of their microscopic behavior.

## Categories within Heat & Thermodynamics

### Internal Energy

Solutions: 174

Internal Energy is the totally amount of energy contained in a thermodynamic system.

### Temperature

Solutions: 277

Temperature is a quantity which indicates how hot or cold a body is.

### Heat Transfer

Solutions: 128

Heat transfer is the study of generation, consumption, and use of thermal energy and heat between physical bodies.

### Heat Engines

Solutions: 103

A heat engine is a system which converts heat or thermal energy to mechanical work.

### Kinetic Theory

Solutions: 56

The kinetic theory explains gases and large number of small particles that are all in constant random motion.

### Specific Heat

Solutions: 77

The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.

### Gibbs free energy and chemical potential

Focus Question: Consider a sample of CaO(s) at 298K and 1 atm. Does the Gibbs energy of the sample increase, decrease of remain the same if the temperature is raised to 350K? Does the Gibbs energy of the original sample increase, decrease of remain the same if the pressure is increased to 2 atm? Important formula 1. For a co

### Entropy change of mercury vaporization at different temperature

1. Consider the system of 20g (0.1 mole) sample of liquid mercury at 1bar of pressure in an open beaker. Given the data below calculate the change in entropy of the universe to vaporize this sample at room temperature (25C). Normal boiling point of Hg is 356.7C. You may assume the heat capacities are constant over this temperat

### First and second law of thermodynamics

1. For the following processes, state whether the driving force is the first or second law of thermodynamics. The systems are in italics and we are only interested in whether the properties of the system have changed. Explain your choice in 1-2 sentences. a. Warming up exercises when muscles are worked the cells "burn" more g

### Calculation of ammonia thermodynamic properties

1. In the table below is the thermodynamic data for ammonia (http://en.wikipedia.org/wiki/Ammonia_%28data_page%29) use this data to solve the following problems for mole of ammonia (state any assumptions you made): a. What is the melting point at standard conditions for ammonia? Boling point is given -33.4C. Assume you have a

### 1-st and 2-nd laws of Thermodynamics

1. Solve both of the following problems a. A sample of an ideal gas has the following initial conditions V=15L, T=250K and P=1atm. It is compressed isothermally until the change in entropy is -5J/K. What are the final conditions? b. Calculate the change in entropy when 50g of 80C water is poured into 100g of 10C water. Assume

### Maximum amount of work that can be extracted from two objects at different temperatures

Consider a system consisting of two objects A and B, when A and B have initial temperature T_A and T_B, and heat capacities C_VA and C_VB independent of temperature. This system is put to work so that it can provide work W, until both reaches a final temperature T_F, where T_A>T_F>T_B. (a) Find the maximum mechanical work tha

### Energy Transfer in Living Organisms

-Define the laws of thermodynamics. Include an example to support your definition. -What is Gibbs free energy? What are consequences for a biochemical reaction when Gibbs free energy is negative? Explain the role of enzymes when Gibbs free energy is negative and when it is positive. -Adenosine triphosphate (ATP) has been ca

### Thermodynamics of a Helium Gas Filled Balloon

A balloon is filled with helium gas at 20.0ºC at 1.0atm (1atm = 1.01x10^5 N/m^2).The volume of the balloon after filling is measured to be 8.50m^3. The helium is then heated at constant pressure until its temperature is 55.0ºC. What is the heat flow into the gas? (CP for an ideal gas is (5/2)R.)

### With temperature increase, how far will the alcohol column move in the tube?

A tube 4.4 mm in diameter is run through the stopper of a sealed 8-liter container. The tube outside the container forms a U, then runs in a straight line with slope .015 with respect to horizontal. Alcohol is introduced into the tube, and fills the U, extending into the linear section of the tube. The end outside the container

### Statistical Thermo Gas Equation

Derive the Ideal gas equation using statistical thermodynamics (ie partition function ect)

### Calculating Elevation Based on Boiling Point: Barametric Formula

See attached file for full description. It is found that a certain liquid boils at a temperature of 95 degrees Celcius at the top of a hill, whereas it boils at a temperature of 105 degrees C at the bottom. The latent heat is 1000 cal/mol. What is the approrimate height of the hill?

### Thermodynamic Equations for Beta and Kappa

Suppose that Beta = (v-a)/T and kappa = 3(v-a)/4P Show that the equation of state is P^3/4 (v-a) = AT, Where a and A are constants. [attachment is copy of problem written with symbols]

### Heat flow through a window

A glass window 0.60 cm thick measures 83 cm by 42 cm. How much heat flows through this window per minute if the inside and outside temperatures differ by 18°C? _______ kJ/min The conversions are confusing me.

### Thermodynamics: Cloud rises on encountering a mountain

A cloud moving across the ocean at 2000 m (height) encounters a mountain range. As it rises to 3500 m, it undergoes adiabatic expansion from p=0.802 to 0.602 atm. If the initial temperature of the cloud is 288 K, will it rain or snow on the mountains? (Assume air to be an ideal gas with Cpm = 28.86 J/mol*K)

### Pressure excerted by a Fermi gas, at absolute zero

Show that the pressure exerted by a Fermi gas at absolute zero is p = (2NEf)/(5V) where N is the total number of particles, Ef the fermi energy and V is the volume. ((If you need to use the relation for the mean energy <E> of particles obeying Fermi-Dirac statistics at absolute zero t

### Vibrations and Harmonic Oscillators

i) Show that the thermodynamic properties of an assembly of N three-dimensional harmonic oscillators are the same as those of an assembly of 3N of on-dimensional oscillators. ii) In the Einstein model, each atom in a solid acts as a three-dimensional simple harmonic oscillator. An atom in a crystal of copper has a typical vib

### Thermodynamics: Mass Flow Rate of Steam

A boiler takes fuel oil of specific gravity 0.81 and calorific value of 27912KJ/KG form a tank 6.0M in diameter. At the time of the maximum firing, the level of fuel oil in the tank is lowered 51mm in one hour, and the absolute boiler pressure is 1620Kpa. What is the mass flow rate of steam from the boiler in KG/HR Note:

### Comparing cost efficiency of two A/C units based on COP

Consider a building whose annual air-conditioning load is estimated to be 120,000 kWh in an area where the unit cost of electricity is \$.10/kWh. Two air conditioners are considered for the building. Air conditioner "A" has a seasonal average COP of 3.2 and cost \$5500.00 to purchase and install. Air Conditioner "B" has a s

### Change of Phase: Joules required

How many joules are required to change one kilogram of ice at -15^oC to water at 15^oC?

### Heating a Gas

Heat required to raise 1 kg carbon dioxide from -100 degrees C to -50 degrees C. I arrived at an answer of 654,657 Joules. I used the following: CO2-solid spec heat = 815 J/kgC CO2-vapor spec heat = 2 J/kgC sublimation point of 573,100 J/kgC Q=CmT CmT(at

### Conceptual physics for mass

Provide a formula and then solve so I can see how to do this type of problem. A block of iron is heated from 22 degrees celcius to 52 degrees celcius, absorbing 6,750j of thermal heat. What is the mass of the block? Solve for mass but need to see formula and how you did this so I can learn this.

### Physics Problem Set

1. A loud speaker is placed between two observers who are 120m apart, along the line connecting them. If one observer records a sound level of 60.0dB and the other records a sound level of 90dB, how far is the speaker from each observer? a: 3.7, 116.3 b: 4.3, 115.7 c: 6.2, 113.8 d: 8.6, 111.4. 2. A room measures 3.0m by

### Phase of matter has fixed volume but not solid

Which phase of matter has a fixed volume and takes the shape of its container?

### Heat Pump Problem

A heat pump is a heat engine run in reverse. In winter it pumps heat from the cold air outside into the warmer air inside the building, maintaining the building at a comfortable temperature... a. If the outside temperature in winter is ... See attached file for full problem description.

### The coefficent

The coefficent of thermal conductivity has the unit a. j/(mk) b. w/(mk) c. j(sk) d.w/(sk)

### Thermodynamics: Heated Rod

At 6 degrees Celsius a metal rod is 1.5 m total length with half the length steel and the other half brass. The rod is heated to 150 degrees Celsius. What is the total change in length?

### Thrust Specific Fuel Consumption for Jet Engine

Refer to the diagram of the JT9-7A TSFC contours (Attached). In terms of the definition of tsfc, explain what is observed on the (T-Mach-tsfc) diagram. See the attached file.

### Calorific Values of Fuel

Explain the difference between upper and lower calorific values of fuel?

### Determine the Thrust Specific Fuel Consumption

Determine the thrust specific fuel consumption (tsfc) for the following conditions for an jet engine in cruise setting altitude producing 10,200 lbf of thrust for a fuel flow of 0.1 kg/s. Express tsfc in units of lb/lbT/hr.

### Air flow speed

The heating and airflow ducts to and from the room are circular 0.30m in diameter, the room is 3mx4.5x6m and the air flow needs to be changed every 12 minutes. Calculate the Air flow speed.