Molecular Physics | Thermodynamics Answers

Calculate the density of bcc iron which has a lattice constant of 2.87 Å and an atomic weight of 55.85.

The energy of the lowest allowed level for an electron in a 1-D box is 10.0 eV. Can the electron ever have an energy of 200 eV? Justify.

In an orthorhombic crystal, a lattice plane makes intercepts of 2a, 3b and 4c on the three axes. Write down the Miller indices for this plane.

The BF_3 molecule has a planar triangular structure with B at the centre. List the symmetries of the BF_3 molecule.

A copper rod ( α = 0.000017 /°C ) is 20 cm longer than an aluminum rod ( α = 0.000022 /°C ). How long should the copper rod be if the difference in their lengths is to be independent of temperature? Hint: For their difference in length not to change with temperature, ΔL must be the same for both rods under the same temperature change.

A particle of mass m moves in a three dimensional box with dimensions a , b , c . Calculate the

allowed energy values.
For a=b=c=L give the first five eigenvalues of the energy and the coresponding degenerate energy levels .


Hint:
Consider solution of this kind: Ψ(x , y , z)=Ψx (x)Ψy ( y )Ψ z(z ) with energy E and solve for
Ψx ,Ψy ,Ψz with energies Ex , Ey ,Ez where E=Ex+Ey+Ez

Derive an expression for adiabatic lapse rate.

If the energy required to change the state of ice to water was 1.68MJ and the specific latent heat of fusion of ice is 226000J/Kg. If this same liquid water has a specific heat capacity of 4200J/Kg degrees celsius and was heated so it's temperature rose by 15 degrees celsius, what extra energy must be supplied to do this.

A bead with mass 2.00 × 10-2 kg is moving along a wire in the positive direction of an x axis. Beginning at time t = 0, when the bead passes through x = 0 with speed 12.0 m/s, a constant force acts on the bead. The figure indicates the bead's position at times t0 = 0.00 s, t1 = 1.00 s, t2 = 2.00 s, and t3 = 3.00 s. The bead momentarily stops at t = 3.00 s. What is the kinetic energy of the bead at t = 10.0 s?

A diver observes a bubble of air rising from the bottom of a lake (where the absolute pressure is 3.50 atm) to the
surface (where the pressure is 1.00 atm). The temperature at the bottom is 4.0°C, and the temperature at the surface is
19.0C° higher. Find the ratio of the volume of the bubble as it reaches the surface to its volume at the bottom? Does
the bubble expand or compress in volume? Assume that the number of moles of gas in the bubble remains constant