Molecular Physics | Thermodynamics Answers

in an air compressor the compression takes place at a constant interval energy and 50 kj of heat and rejected to the colling water for every kilogram of air. calculate the work input for the compression stoke per kilogram of air

Oxygen O2, at a pressure of 200 bars, will be contained in a steel container at a temperature of 20 oC.
The volume of the container is 0.04 m3. Assuming that O2 is an ideal gas, calculate the mass of O2 which can
be contained in the container.
The container is protected against excessive pressure by a fusible plug which will melt if the temperature
goes too high.
Calculate at what temperature the fuse plug will melt if the pressure is limited to 240 bar.
(The molar mass of oxygen = 32 Kg / Kmol and Ru = 8314 J / Kmol K)

1) Smoke from a burning rubbish heap is observed to move upwards in a wavy manner. Explain:
(i) why the smoke moves upwards
(ii) why the movement is wavy
(iii) how the movement of the smoke is different from Brownian motion

2) Hot tea from the same flask is served into two cups of the same shape and same volume, one made of glass and the other of silver. State, giving reasons in each case
(a) which cup of tea colds fast
(b) the method of heat transfer by which the two cups lose heat at the same rate

How much heat is absorbed by 60 g of copper when its temperature is
raised from 20 °C to 80 °C?(specific heat capacity of copper = 900 J/kgK)

a)Suba (m=72.6 kg) is skiing from a hill. She is standing at 28.5 m from the earth surface level.
i.Calculate Suba’s gravitational potential energy at the top.
ii.Calculate Suba’s kinetic energy at the top.
iii.Calculate total mechanical energy at the top.
iv.Calculate Suba’s kinetic energy and gravitational potential energy at the halfway down point from the top.
v.Calculate Suba’s kinetic energy at the bottom of the hill.
vi.Calculate Suba’s speed at the bottom of the hill.

b)The temperature of the water decreases to 0 °C in 10 minutes.
(specific heat capacity of water = 4200 J kg-1K–1)
Calculate,
i. the energy lost by the water when the temperature decreases to 0 °C.
ii. the average rate at which the water is losing energy, in J s–1.
iii. the time is taken for the water at 0 °C to turn completely into ice.
(The specific latent heat of fusion of water = 3.3 X 105 J Kg-1)

An ice sculpture is made of 55 kg of ice and is stored at –22˚C. Heat is turned on instead of the cold and evaporates all the ice into steam at a temperature of 115˚C. How much heat was added to the sculpture to create the sauna? (grade 11 physics)

Ten moles of a monaatomic ideal gas initially has a volume of 0.800m3. The gas undergoes four processes: 1) without changing its temperature, the gas expands to a volume of 1.200m3, at which point its pressure is 20.00KPa, 2) The gas expands to a volume of 1.480m3 without heat entering or leaving the gas. 3) without changing its temperature, the gas is compressed until its pressure is 21.15KPa. 4) The gas is compressed to a pressure of 30.00KPa without heat entering or leaving the gas.
I) calculate the work done by the gas in processes 1) and 3).
II) Determine the process that the gas undergoes
III) Using the definition of the entropy, calculate the total change in entropy during the four processes. Comment on your answer.

If the Fermi energy of silver is 5.5 eV, the wave number of the fastest electron at 0 K has the magnitude in (meter)^-1 is?

Assuming the ideal C/a ratio for the HCP Ti (with a=2.95 Angstrum ), the radius of the largest sphere that will fit interstitially in Ti is?

If the activation energy for oxidation is 100 KJ mole^-1 , the ratio of oxidation rates at
800 degree Celcius and 500 degree Celcius is ?