Explore BrainMass

Explore BrainMass

    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. 

    © BrainMass Inc. brainmass.com May 25, 2024, 3:46 am ad1c9bdddf

    BrainMass Solutions Available for Instant Download

    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

    Thermodynamics Problems

    A closed vessel containing 0.06m^3 at air at 40 atmospheres and 40 degrees Celsius is connected with another closed vessel containing 1.35 kg of argon at 7 atmospheres. When the valve separating these vessels is opened, the pressure of the mixture is 18 atmospheres and its temperature is 30 degrees Celsius. Determine the volum

    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

    Calculate the mass of helium in the cylinder.

    A piston cylinder assembly whose piston is resting on a stop contains 400 L of helium gas, initially at 200 kPa and 25 degrees celsius. The mass and the atmospheric pressure acting on the piston are such that a pressure of 500 kPa is required to raise it. At the final state, the volume of helium gas is doubled. a) Calculate

    Example for Laws of Thermodynamics

    During the first oil crisis of the early 1970s, a business entrepreneur placed an expensive full-page advertisement in the New York Times, appealing to "the ingenuity of the American people." He offered a cash reward to any inventor who could "raise the temperature of a metal rod by cooling a second rod" and then "generate power

    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!

    First Law of Thermodynamics and Acceleration of a Car

    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. http://www.mhhe.com/physsci/physical/giambattista/thermo/thermodynamics.html ================================================== 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.

    Thermodynamics - Warm Up Air

    You warm 1.75 kg of water at a constant volume from 17.0C to 32.0C in a kettle. For the same amount of heat, how many kilograms of 17.0C air would you be able to warm to 32.0C? Make the simplifying assumption that air is 100% N2. What volume would this air occupy at 17.0C and a pressure of 1.10 atm?

    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.

    Heat Transfer and Work Done During Polytropic Process

    Oxygen at 300 kPa and 100 degrees C is in a piston, cylinder arrangement with an initial volume of 0.1 cubic meters. It is then compressed in a polytrophic process (P*v^n=constant) with n=1.2 to a final temperature of 200 degrees C. a) Calculate the heat transfer for the process. b) Draw a P V diagram for the process.

    Applied Heat Thermodynamics

    Please help with the problems involving applied heat thermodynamics. 3. Calculate the change in enthalpy during a compression process in which the work done on the working medium is 24 kJ, and the change in internal energy is 36 kJ. Heat added or rejected 4. Derive the numerical ratio ----------------------------

    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

    Kinetic and Ideal Gas Law Questions.

    Question 1: The figure below is a plot of Fahrenheit temperature versus Celsius temperature. (a) Is the value of the y-intercept found by setting 1. TF = TC 2. TC = 0 or 3. TF = 0? (b) Compute the value of the y-intercept. (c) What would be the slope and y-intercept if the graph were plotted the opposite way (Celsius ve

    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