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# Internal Energy

### Ideal Gases & Constant Heat Capacity

1. An ideal gas with Cp/Cv=1.5 where Cp and Cv are respectively the heat capacities at constant pressure and constant volume, is used as the working substance of a Carnot engine. The temp of the source is 600K and that of the sink is 300K. The volume of gas changes from 4 to 1 liter at the low temp and the pressure at the vol

### Thermodynamics 1st Law Equation

Question on a system involving temperature, pressure and volume is attached.

### Thermodynamics 1st Law

The following are first law problems in Thermodynamics: 1. The molar energy of a mono atomic gas which obeys van der waals equation is given by: E =(3/2)*RT - (a/V) where V is the molar volume at temperature T, and a is a constant. Initially one mole of the gas is at temperature T1 and occupies vol

### Heat content or Btu value of water at various temperatures?

Help?? Where can I find the Btu value or heat content of water at various temperatures such as 50, 60, 70, 80, 90 & 100 degrees F? Say 1 lb of water. Is it also generally safe to say that if the water is in contact with another surface, that the water will give up its heat content so long as the adjoining mass is cooler th

### Heat and Thermodynamics

1. You have a 16 oz cup of coffee at 180 degrees F. That is way too hot to drink. So you want to cool the coffee off and decide to add some cold water. You add 2 ounces of cold water at 40 degrees F. How much will the water you added heat up? How much will the coffee that you poured the water into cool down? 2. An ai

### Each of three bodies has a temperature-independent heat capacity C. The three bodies have initial temperatures of T1, T2, and T3 . What is the maximum amount of work that can be extracted leaving the three bodies at a common final temperature?

Each of three bodies has a temperature-independent heat capacity C. The three bodies have initial temperatures of T1, T2, and T3 . What is the maximum amount of work that can be extracted leaving the three bodies at a common final temperature?

See attached files.

### Heat flow and work done by an ideal gas.

When a system is taken from state a to state b in the figure View Figure along the path acb, the amount of heat that flow into the system is 95.0 J and the work done by the system is 57.0 J. A) How much heat flows into the system along path adb if the work done by the system is 10.0 J? B) When the system is returned from

### We consider a classical ideal gas of N particles of mass m which are independent of each other and are in a volume V. The particles are in an external potential which has a value epsilon in a part volume v < V and the value 0 in the remaining area V - v. During compression only the volume V changes, i.e. v is constant.

See attached file.

### Entropy and chemical potential

For a diatomic gas near room temperature, the internal partition function is simply the rotational partition function multiplied by the degeneracy Ze of the electronic ground state. (a) Show that the entropy in this case is S = Nk [ln (VZeZrot/NvQ) + 7/2. Calculate the entropy of a mole of oxygen (Ze = 3) at room tempe

### Work, entropy, and the ideal gas law

See attached file. A balloon filled with 40 moles of He at 3 atm pressure and at room temperature (300 K) expands isothermally from a volume Vi to a volume Vf till its pressure falls to 1 atm. (a) What are Vi and Vf? Here's what I did for this one: PV = nRT Vi = nRT/P = (40)(8.315)(300K)/[3*(1.013 x 105 N/m2) = 0

### PV Diagram Isobar

A small container of gas undergoes a thermodynamic cycle. The gas begins at room temperature. First the gas expands isobarically until its volume doubles. Then the gas expands adiabatically. Then the gas is cooled isobarically and finally the gas is compressed adiabatically until it returns to its original state. (a) Draw a

### Entropy derivations for an ideal 2-state paramagnet

Consider an ideal 2-state paramagnet. The entropy is given by: S = k [N ln N - Nu ln Nu - Nd ln Nd], where Nu and Nd are related to total number N, internal energy U, magnetic field B and magnetic moment &#956; by Nu = (N - U/&#956;B)/2, Nd = (N + U/&#956;B)/2 (a) Use the relation T-1 = (&#8706;S/&#8706;U)N,B

### Quasistatic isothermal expansion and free expansion

During the quasistatic isothermal expansion of a monoatomic ideal gas, how is the change in entropy related to the heat input Q by the simple formula: ΔS = Q/T? Why isn't this valid for the free expansion process?

### How much heat entered the gas from point To to point A?

An ideal gas at pressure, volume, and temperature Po, Vo, and To, respectively, is heated to point A, allowed to expand to point B at 2To, and then returned to the original condition. The internal energy increases by 3PoVo/2 going from point To to point A. How much heat entered the gas from point To to point A?

### Eddy Currents Field Direction Rotations

An aluminium cylinder rotates as it falls through a uniform magnetic field. Let it be falling in the y direction and the field direction be z. When its axis of rotation is perpendicular to the field direction (along the x axis), it slows down. When it is parallel to the field direction there is no braking. Why?

### Internal Energy of Ideal Gas

To the nearest joule what is the total internal energy of 14 moles of a monatomic ideal gas at a temperature of 315 K?

### Thermodynamics: Work done, heat transfer and internal energy

(See attached file for full problem description) 0.110 moles of a mono atomic gas follows the process shown in the figure Part A How much heat energy is transferred to or from the gas during process 1 to 2? Part B How much heat energy is transferred to or from the gas during process 2 to 3? Part C What is the tota

### Energy of the Molecules of an Ideal Gas

What determines the energy of the molecules of an ideal gas??

### Energy of doing exercise

Energy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is one kilocalorie, defined as 1 kcal = 4186 J. Metabolizing one gram of fat can release 9.00 kcal. A student decides to try to lose weight by exercising. She plans to run up and down the stairs in a football stadium as fast as she can a

### Work by Gas in Cylinder

A gas in a cylinder is held at a constant pressure of ... Pa and is cooled and compressed from... See attached file for full problem description.

### Thermodynamics: Two Step Process

Question: Consider the following two-step process. Heat is allowed to flow out of an ideal gas at constant volume so that its pressure drops from P1 = 2.19 atm to P2 = 1.58 atm. Then the gas expands at constant pressure, from a volume of V1 = 6.38 L to V2 = 10.5 L, where the temperature reaches its original value. See the attach

### Tension, work done and increase in internal energy

A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope. The rope is inclined at 20.0° above the horizontal, and the sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.550. (a) What is the tension in the ro

### Work and Energy - Volume, Pressure and Temperature

1. You have a 16 oz cup of coffee at 180 degrees F. That is way too hot to drink. So you want to cool the coffee off and decide to add some cold water. You add 2 ounces of cold water at 40 degrees F. How much will the water you added heat up? How much will the coffee that you poured the water into cool down? 2.

### Energy absorbed per house; pressure in gas; mass

Hi, I need help with these problems; would you help me? Thank you. 1) A Carnot engine has a power output of 150 kW. The engine operates between two reservoirs at 20.0C and 500C. How much energy does it absorb per hour? 2) The internal energy in a monatomic ideal gas is 2.00 * 10^4J. The volume of the gas is 2.00 liters. Wh

### Enthalpy of Aircraft Gas Turbine Conponents

Relate the work done in components of an aircraft gas turbine to enthalpy changes in these components. How does the actual work output relate to the temperature changes for a similar but isentropic process?

### Simple Ways of Expanding in thermodynamic processes

Please see attached file for full problem. Simple Ways of Expanding Part A What type of process does curve OA represent? A) adiabatic B) isobaric C) isochoric D) isothermal Part B What type of process does curve OC represent? A) adiabatic B) isobaric C) isochoric D) isothermal Part C The pressure of the s

### Maximum possible efficiency

An individual walking the roads at night indicates an invention he is working on produces 55KW with 70KW of thermal energy supplying it. The cold side is at 40C, the hot side at 1650C. Is this something to consider further? Explain.

### Ideal gas equation, Internal Energy, Equipartition of energy principle

1. A scuba tank has a volume of 3500 cm³. The tank is filled with 50% (by volume) pure oxygen and 50% (by volume) pure helium. (a) How many molecules are there of each type in tank if it is filled at 20ºC to an absolute pressure of 11 atmospheres? (b) What is the ratio of the average translational kinetic energies of the t

### Suraj Joshi - clarification required - wet steam properties

Suraj, Firstly, thanks for your initial answer, and apologies for not rating it. I didn't realise I needed to rate it upon receipt, rather than when convenient. If you could just clarify a couple of points relating to your answer though, we'll have another go at the rating bit. (1) "At critical point of water, T= 647.1