Atom questions

3. A material has an effectively full valence band and an empty conduction band. Explain why that if these two bands overlap the material behaves as a metal and if they are separated by a few electron volts in energy the material is an insulator. 4. Calculate the minimum energy a photon must have to produce an electron hole p ...continues

The temperature of the sea bed 60 m below the surface and at the surface are both 20C...

12. The temperature of the sea bed 60 m below the surface and at the surface are both 20C. A rubber balloon is inflated at the sea bed with 2.0 mole gas neglecting the works done on the rubber determine: i)the volume of the balloon at the sea bed and ii) the volume of the balloon after it has been allowed to float slowly up t ...continues

One mole of ARGON gas inside a cylinder...

2. One mole of ARGON gas inside a cylinder fitted with a piston is made to expand very slowly in good thermal contact with its surroundings. During this expansion the volume was doubled and the temperature was constant. The same expansion is performed very rapidly with the cylinder being thermal isolated. The conditions were con ...continues

Question set

1)Which of following energies indicates the order of magnitude of the band gap in between the conduction and valence bands in a semi-conductor: a) 10^2 electron volts b) 0.7 electron volts c) 10^-8 volts 2)How many degrees of freedom does a point atom have: a) 15 b) 4 c) 3 d) 1 4)A pi ...continues

Electron questions

1. Explain how the degree of filling of an electron level in an isolated atom of molecule affects whether the resulting solid is an insulator, semi-conductor or metal. 2. Hence or otherwise compare the expected electrical conductivity of solid hydrogen with solid helium.

2 Questions

1.a) state the assumption associated with the model used to develop the Ideal Gas Law b) hence or otherwise describe under which physical conditions does the ideal gas law applies 2. Explain why hydrogen which has one electron in its lowest state, should in principle be a metallic conductor in its solid state whereas heli ...continues

2 Questions

3. How is the ideal gas law modified to account for the finite volume of molecules? 4. The temperature of the sea bed 60 m below the surface and at the surface are both 20C. A rubber balloon is inflated at the sea bed with 2.0 mole gas neglecting the works done on the rubber determine: i)the volume of the balloon at the se ...continues

2 Questions

3. Argon gas is composed of point atoms and oxygen gas is composed of linear molecules of the form O---O where O denotes an oxygen atom. Determine the ratio of the specific heats at constant volume for these two gases. 4. Describe two different ways by which electrons can move from the valence band to the conduction band.

Chem question

ChemA-$1.5/gallon-must use 25 gal ChemB-$3.75/gallon-??? gal Solution-$2.5/gallon-no limit how many gal of chemB is needed to get solution at$2.50 a gallon?

Calculate the concentrations of the protoneated and unprotonated forms of bromothymol blue

Calculate the concentrations of the protoneated and unprotonated forms of bromothymol blue in 100 mL of a pH 8.1 buffer solution to which 1.0 mL of 0.005 M solution of bromothymol blue in 80% wate/20%ethanol has been added. Calculate the pH of the buffer solution that results when 10 mL of 0.10 M NaH2PO4 added to 3 mL of 0.05 ...continues