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# First Law of Thermodynamics

### 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

### Thermodynamics: Adiabatic process, P-V graph, final P and T

Air containing gasoline vapor is admitted into the cylinder of an internal combustion engine at 1.0 atm pressure and 30 degrees C. The piston very rapidly compresses the gas, which you may pretend is all air, from 500 cc to 50 cc; a compression ratio of 10. Find the final T and P of the gas. The gas gets hot, but why (was it hea

### 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 litre tank is stored in a 15 degree C room. Its gauge reads 280 psi. A 50 litre 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. Wha

### First Law of Thermodynamics Question

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

### At the beginning of a compression process of an air-standard Otto cycle

At the beginning of a compression process of an air-standard Otto cycle, p1 = 1 bar, T1 = 290 K, V1 = 400 cm^3. The maximum temperature in the cycle is 2200 K and the compression ratio is 8. How to determine the mass of air contained in the system, in kg, and the heat addition, in kJ? The internal energy at the end of the isentr

### Thermodynamics: Air-Standard Otto Cycle

At the beginning of a compression process of an air-standard Otto cycle, p1 = 1 bar, T1 = 290 K, V1 = 400 cm^3. The maximum temperature in the cycle is 2200 K and the compression ratio is 8. How do I determine the mass of air contained in the system, in kg, and the heat addition, in kJ? The internal energy at the end of the isen

### 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.

### Piston-Cylinder Device

A piston-cylinder device contains 5 kg of refrigerant-134a at 800 kPa and 60 degrees Celsius. The refrigerant is now cooled at constant pressure until it exists as liquid at 20 degrees Celsius. Determine the amount of heat loss and show the process on a T-v diagram with respect to saturation lines. Please show steps.

### Thermodynamics for Stoichiometric Tables

Please see the attachment. I think for some of these exercises 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. 1. Oilseed protein sources include soybean, cottonseed, peanut, sunflower, copra, rapeseed, sesame, safflower, cas

### 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

### From Hot to Cool: The Second Law of Thermodynamics

Please do not place your response in a .pdf or .cdx format, but Word documents are okay. Thanks! Please see attached for actual problem.

### Heat absorbed by monoatomic ideal gas

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

### Salt crystals evaporated from salt solution with high degree

Water evaporates from a salt solution and leaves behind salt crystals that have a higher degree of molecular order than the more randomly moving molecules in the salt water. Has the entropy principle been violated? why or why not?

### Energy and the Laws of Thermodynamics

What is energy? Describe the two laws of Thermodynamics and give several examples.

### Fuel Economy and Second Law of Thermodynamics for Otto-cycle of a certain car

The Otto-cycle of a certain car has a compression ratio r=8.5. The fuel economy rating of this car is 25 miles per gallon at 105km/h. Gasoline has a heat of combustion of 4.60x10^7J/kg, and its density is 740kg/m^3. a. At 105km/h, what is the rate of gasoline consumption in L/h? b. What is the theoretical efficiency of

### Biological Evolution and 2nd Law of Thermodynamics

Some people claim that biological evolution violates the second law of thermodynamics, since evolution involves simple life forms developing into more complex, more highly ordered organisms. Why is this argument wrong? I'm pretty sure that the answer lies in the definition of entropy. Doesn't entropy limit itself to energ

### Laws of thermodynamics : Changes in internal energy.

The specific heat of air at constant volume is 0.175 cal/gm deg Celsius a) By how much does the internal energy of 5 gm of air change as it is heated from 20 deg to 400 deg? (b) Suppose that 5gm of air is adiabatically compressed so as to raise its temperature from 20deg to 400 deg. How much work must be done on the air to

### Boundary Work and Final Temperature in a Piston Cylinder

One tenth kilogram of Argon is contained in a piston-cylinder assembly. Initially at 4900 K and a volume of 40 liters, the gas undergoes an isobaric process during which the heat input is 30 kJ. Determine the boundary work and final temperature.

### Perpetual Motion Layman's Terms

Why is perpetual motion impossible on earth?