Molecular Physics | Thermodynamics Answers

Air is contained in a vertical piston-cylinder assembly fitted with an electrical resistor. The atmospheric pressure is 100 kPa and point has a mass of 50 kg and a face area of 0.1 m². Electric current passes through the resistor, and the volume of of air slowly increases by 0.045 m³. The mass of the air is 0.3 kg, and its specific energy increases by 42.2 kJ/kg. Assume the assembly ( including the piston) is insulated and neglect the friction between the cylinder and piston, g = 9.8 m/s². Determine the heat transfer from the resistor to air for a system consisting of (a) the balloon, (b) the air and the piston

1. How much heat is required 200 mL of ice at - 22 degrees Celsius (at typical Freezer temperature).
2. One mole of a monoatomic perfect gas initially at temperature T₀ expands From volume V₀ to 2V₀ (a) at constant temperature, (b) at constant pressure. Calculate the work of expansion and the heat absorbed by the gas in each case.
3. Determine the mass and specific volume of argon gas in a vessel at 150 kPa and 20 degrees Celsius. The vessel is spherical and has a radius of 5m.
4. A container which has a volume 0.1 m³ is fitted with plunger enclosing 0.5 kg of steam at 0.4 MPa. Calculate the amount of heat transferred and the work done when the steam is heated to 300 degrees Celsius at constant pressure.

what is temperature

Calculate the probability that the speed of a chlorine molecule will lie between 200 m s−1 and 220 m s1 at 300 K. Given that mass of chlorine molecule = 70u, kB = 1.38 × 1023 JK1 and NA = 6.02 × 1026 kmol1

A Carnot's engine whose low temperature reservoir is at 7°C has an efficiency 50%. 

By how many degrees should the temperature of the high temperature reservoir be increased to increase the efficiency to 70%?

One gram mole of a monoatomic perfect gas λ =5/3 at 27° C is adiabatically compressed from an initial pressure of 1 atm to final pressure of 50 atm. Calculate 

the resulting final temperature.

A resistor initially at 300 K has a heat capacity of 10 J K⁻¹ . It is thermally insulated from its surrounding and is connected to a battery from which it takes 1200 J through an electric current. Calculate the change in entropy of (i) the resistor, 

(ii) the surroundings.

For a given gas the coefficient of viscosity is 1.9 × 10⁻⁵ N s m⁻²

and the diffusion coefficient is 1.2 × 10⁻⁵ m² s⁻¹. Calculate the density and mean free path at average molecular velocity of 380 m s⁻¹.

Calculate the temperature at which the root mean square velocity of a chlorine molecule will be equal to its escape velocity from the earth’s gravitational field. 

Given that the radius of earth is 6400 km.

Calculate the probability that the speed of a chlorine molecule will lie between 200 m s^-1 and 220 m s^-1

at 300 K. Given that mass of chlorine molecule = 70u, k_B = 1.38 × 10^-23JK^-1 and NA = 6.02 × 1026 kmol

and N_A= 6.02×10²⁶ kmol⁻¹.