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First Law of Thermodynamics

The first law of thermodynamics is a version of the law of conservation of energy that is adapted for thermodynamic systems. The internal energy of an isolated system is constant and energy can be transformed from one form to another but cannot be created or destroyed. The first law is often formulated by stating that the change in the internal energy of a closed system is equal to the amount of heat supplied to the system, minus the amount of work done by the system on its surroundings.

The first law of thermodynamics states

ΔU = Q – W 

Where ΔU is the change in internal energy, Q is the heat added to the system and W is the work done by the system.

This law makes use of the key concepts of internal energy, heat and system work. It is often used to the discussion of heat engines

Application of Thermodynamics for Heat Transfer Through a Wall

An insulated frame wall of a house has an average thermal conductivity of 0.0318 Btu/h-ft^2-R degrees. The wall is 6 in thick and it has an area of 160 ft^2. The inside air temperature is 70 degrees F and the heat transfer coefficient for convection between the inside air and the wall is 1.5 Btu/h-ft^2-R degrees. On the outside

2nd Law of Thermodynamics

Please see attachment for original question format. A combined air filled, spring loaded cylinder has a frictionless piston of area 0.012 m^2 that rests against the spring. The spring loaded end of the cylinder is open to atmosphere. The spring force in terms of piston movement is given by: Spring Force = k X Show that

help with a short essay

I need to write a short paper and am clueless as to where to start. The question is: Divine Personalities verses material objects, what was God thinking? The task is: Identify, then list reasons for a preference for thinking of the stars, moon, and planets as material objects or as divine personalities. Help please!

List ways of using math to communicate.

The word acceleration means that something is speeding up or slowing down …….its speed (velocity) is changing. If you are driving on the highway at 60 mph then you are going at a constant speed (velocity) there is no acceleration. If you change your speed up or down, then, during the time that the speed was being changed y

Physics: Second Law of Thermodynamics

1. Use the second law of thermodynamics to explain why many poor people in developing countries live on a mostly vegetarian diet? 2. Someone wants you to invest money in an automobile engine that will produce more energy than the energy in the fuel (such as gasoline or electricity) used to run the motor. What is your response

Carnot Heat Engine and Well-Insulated Piston Cylinder Systems

Problem 1 can only be solved per unit mass- eg work per unit mass, volume per unit mass, since there is not enough info to calculate the system mass. Instructions: Solve the following problems. Be sure to include a sketch indicating the system and its interactions with the surroundings and state all necessary assumptions. Ide

Experiment to demonstrate the Ideal Gas Law.

Experiment to demonstrate the Ideal Gas Law. Attached is the directions and data sheet. Here is the link for the data sheet. ================================================== Data and related questions ==========================================

Heat transfer & thermodynamics relative to water and wood

In our ChemE lab, we were asked to place a 25 cm x 25 cm x 1 cm (thick) block of wood in a water bath.....the rate of water absorption into the wood block is known to be 8 grams/100 cm^2 at 20 degrees C --- and the wood block is assumed to be at normalized ambient temp as well and completely dry or free of moisture before enteri

Work done by expanding piston

Air expands inside a horizontal cylinder with a piston. The initial volume is 1.0 ft^3, and the initial pressure is 1500 psia. The air expands to 8.0 ft^3, with pV^1.4=constant. Sketch the system (5 points), and calculate the work done (20 points).

Thermodynamics & Newton's law of cooling

(Please see the attachment for detailed problem description) Distinguish between reversible and irreversible processes in thermodynamics. Describe the circumstances under which a) dQ = Tds and dW = -PdV. A long cylinderical rod of radius R is attached to a source of heat at one end and its surroundings are at temperature

Laws of Thermodynamics

As a patent agent, an inventor comes to you claiming that he has invented a self-powered engine that requires no fuel to run. Will you agree or disagree to patent this invention? Why or why not? Use the first law of thermodynamics to help justify.

Laws of Thermodynamics

We can say that life on earth is supported by the sun as the ultimate energy source and that life on earth would not exist without this source of energy. How does this statement relate to the two laws of thermodynamics? Please provide examples.

Steady Flow Turbine

Steam at 800 kPa, 600°C enters a steady flow turbine and leaves at 100 kPa. The steam undergoes an expansion process through the turbine, does work in the amount of 600 kJ/kg, and loses 50 kJ/kg of energy by heat transfer to the surroundings. (a) Determine the exit temperature of the steam, in °C. (b) If the surroundings

Rate of heat supplied from a pump

Air from inside a house enters a steady-flow heat exchanger with a volume flow rate of 200 m3/min at 15°C, 100kPa and eaves the heat exchanger at 35°C. This heat exchanger is located inside the sir handler of a house heat pump system and receives heat from the heat pump. The heat pump receives heat from air outside the house

Calculations Regarding a Piston-Cylinder Device

A piston-cylinder device contains 5kg of steam at 100kPa, quality of 50%. This steam undergoes two processes as follows: (Process1-2) Heat is transferred to the steam in a reversible manner while the pressure is held constant until the steam exits as a saturated vapor. (Process 2-3) The steam is compressed in an adiabatic, rev

Thermodynamics on a Reversible Heat Engine

By operating a reversible heat engine with an ideal gas as the working substance in a Carnot cycle and measuring the ratio QL/QH, we can calculate: a. n, the number of moles of the ideal gas b. the ratio VL/VH of the volumes of the ideal gas. c. the ratio PL/PH of the pressures of the ideal gas. d. the ratio PLVL/PHVH of t

Psychrometry-Hot House

3) SOLVE THIS PROBLEM BELOW: Hothouse Problem A hothouse needs to be kept at a constant temperature of 30°C drybulb and 60% relative humidity (state K) throughout the year. The air flowrate out of the hothouse is 5 m 3 /s . 40% of this air must be replaced by outside air. In winter the air is at 8°C and 90% relativ

Air Handling Unit

THE FINAL SOLUTIONS TO THIS PROBLEM ARE: a) 8.9 degrees celcius b) 318.1 KW c) 92.11 KW Outside air at 32°C and a pressure of 1.013 bar is drawn into an air handling unit at a rate of 5m3/s. The air has a relative humidity of 66.5%. The unit must deliver air to a building at 25°C and 36%relative humidity. Determine: i.

Free energy equation - The relationship between dG=dH-TdS (d stands for delta)

I'm having trouble understanding the 2nd law of thermodynamics in it's relationship to entropy. This is probably the reason why i can't seem to grasp the components of the free energy equation dG=dH-TdS What i do know is this, that if dG<0 the reaction is spontaneous (exergonic) and if dG>0 the reactions is nonspontaneous

Problems on heat and thermodynamics

1. A cube 10 cm on each edge contains air (equivalent molar mass 28.9 g/mol) at atmospheric pressure and temperature 27 degree C. Find the mass of gas, its weight, and the force it exerts on each face of the cube. Comment on the physical reason why such a small sample can exert such a great force. 2. In a time t, N hailst

Heat and Thermodynamics: Gas laws

1. A 24 liter tank is stored in a 15 degree C room. Its gauge reads 280 psi. A 50 liter tank is stored in a 34 degree C room. Its gauge reads 425 psi. The two tanks are then joined by a piece of tubing, the combination being placed in a 0 degree C cooler. However, in the connection process 8 percent of the total gas is lost. Wh

First Law of Thermodynamics

Two 800-kg cars moving at a velocity of 90 km/h have a head-on collision on a road. Both cars come to a complete rest after the crash. Assuming all the kinetic energy of cars is converted to thermal energy, determine the average temperature rise of the remains of the cars immediately after the crash. Take the average specific he

Combustion Reactions (Thermochemistry)

1. Gaseous Propane at 25 degrees C is burned with moist air at 400K in a steady state, steady flow process. The combustion process is adiabatic, and the exiting temperature is measured to 1200K. A sample of the products is tested and found to have a dew-point temperature of 70 degrees C. Determine the percentage of theoretical a

Tank Work

A 10-ft^3 tank contains oxygen initially at 14.7 psia and 80 degrees F. A paddle wheel within the tank is rotated until the pressure inside rises to 20 psia. During the process 20 Btu of heat is lost to the surroundings. Determine the paddle-wheel work done. Neglect the energy stored in the paddle wheel.


Please see the attachment. I think for some of these excersices you will have to setup stoichiometry tables, and there is the in/out thing going on. I know it's not complicated, it's just I missed the material.

Thermodynamics of Varying Stations

Air flows through the converging-diverging nozzle. The conditions at the inlet side are at standard atmospheric conditions, while the density and the temperature at station B is 0.060 lbm/ft3 and 30.5 degree Fahrenheit. Also, the density at station C is 0.050 lbm/ft3, with the velocity at station A recorded to be at 380 ft/s. D


How much heat is needed to heat one mole of an ideal monatomic gas from 100K to 500 K at constant volume? choices in answers are a. 5kJ b. 8kJ c. 49J d. 82kJ