Molecular Physics | Thermodynamics Answers

In deep space, the dumber density of atoms is 10^6 atoms/m^3 and the temperature is 2.7K. What volume in cubic meters is occupied by 1.5 mol of gas? If this volume is a cube, what is the length of one of its edges?

The number density of gas atoms at a location in the space above Earth is 0.85x10^11 m^-3, and the pressure is 2.95x10^-10 Pa. What is the temperature in this region?

A boat travels at the rate 25 in still water. If the rate of the current is 18 , what is the rate of the boat
a. upstream
b. downstream
c. across the river?

9 If three persons, on an average, come to a company for job interview per day, then
determine the probability that less than three people have come for an interview on
a given day.
10. The variation of the specific heat capacity of air with temperature is given in the
following set of data:
Heat Capacity
(in kJ kg−1
K−1
)
1.003 1.005 1.008 1.013 1.020 1.029
Temperature (in K) 250 300 350 400 450 500
Compute the correlation coefficient rXY.
******

Define thermodynamic probability (W) of the macrostate. Establish the relation
between entropy (S) and W.

Define first order phase transition. Derive the Clausius-Clapeyron equation. Plot
(a) entropy, and (b) Gibbs function as a function of temperature for a first order
phase transition.

The specific heat capacity Cv (J K-1 mol-1) of copper at different temperatures varies as follows
T (K) 1.4 2 2.44 2.83 3.16 3.46 3.74
Cv(J K-1 mol-1 5.26 10.0 16.3 22.5 29.1 37.6 45.33
Calculate the value of γ in the equation Cv = γT + αT3 and the Debye temperature Td. Assume that the number of electrons per unit volume of copper is 8.5 x 1022 cm-3.

A molecule has a triply degenerate excited state lying at 300 cm-1 above the non-degenerate ground state. At what temperature will 20 percent of the molecule be in the upper (excited) level?

2 kg of water is heated from 0°C to 100°C and converted into steam at the same
temperature. Calculate the increase in entropy, given that specific heat of water is
4.18 × 103
J kg−1
K−1
and Latent heat of vaporisation is 2.27 × 107
J kg−1

a) What is transport phenomenon? Obtain an expression for:
i) the average number of molecules crossing an arbitrary plane from either side per
unit area per second is n ,v
ii) the average height at which a molecule makes its last collision before crossing
the plane is .
3
2
λ
iii) Using the results in (i) and (ii) obtain an expression for viscosity of the gas.
iv) Discuss its pressure and temperature dependence.