3.Half-life for disintegration of radium is 1590 years. Calculate the rate constant in s^-1. Also, how many years will be taken for the disintegration of 80 % ? (Hint: First-order reaction.)

1.One mole of ideal gas initially at 27°C is compressed adiabatically  from 6 dm3 to 3 dm3 against constant external pressure of 15 atm. Calculate AE，AH, Q, and W for this process. (Note: The heat capacity at constant volume is 20.91 Jmor-1K-1. 1 atm = 101.325 kPa, 0°C = 273 K.)

2.Show that entropy change in a binary mixture for isothermal process is maximum when x1 = x2 = 0.5, where Xi is the mole fraction of component i.

【已刪除】4.Consider the cell The emf of the cell at 15°C is 0.67531 V and the temperature coefficient of emf is — 0.00065 V K'1. Calculate the value of AH at 15°C and heat flow if the process is carried reversibly.  [The cell reaction is: Cd(s) + 2AgCl(s) CdCl2(s) + 2Ag(s)]

5.(1) Calculate the change of free energy for an isothermal reversible expansion process if the pressure of one mole of ideal gas drops from 100 atm to 20 atm at 25°C.

(2) Calculate the AG if the expansion is carried against a constant pressure of 2 atm. Other conditions remain the same as in (1).

1. How can both n-type and p-type semiconductors be produced from pure silicon, respectively? Explain how n-type and p-type semiconductors increase electrical conductivity over that of pure silicon?

2. At elevated temperatures, NaClC3 decomposes to produce sodium chloride and oxygen gas. A 0.8765 g sample of impure NaClO3 was heated until the production of oxygen gas ceased. The O2 gas collected over water occupied 57.2 mL at a temperature of 22°C and a pressure of 734 torr. Calculate the mass percent of NaClC3 in the original sample. (Na = 22.99, Cl = 35.45, O = 16.00. At 22°C the vapor pressure of water is 19.8 torr)

3. When the supply of oxygen is limited, iron metal reacts with oxygen to produce a mixture of FeO and Fe2C3. In a certain experiment, 40.00 g iron metal was reacted with 22.40 g oxygen. After the experiment, the iron was totally consumed, and 6.48 g O2 gas remained. Calculate the mounts of FeO and Fe2O3 formed in this experiment. (Fe = 55.85)

4. Draw all the structural and geometrical (cis-trans) isomers of C3H5CI.

(a) sodium peroxide