SOLUTIONS

                              DATE OF SUBMISSION: 02/07/2017

1.       Define the following  (1)mole fraction (ii) molarity (iii) molality

2.       State  Henry’s law and give its applications.

3.       State Raoults law for volatile compounds.

4.       Taking suitable examples explain the ,meaning of positive and negative deviations from Raoults law.

5.      Suggest the most important type of intermolecular interactions in the following pairs.

(i)                 n-hexane and n-octane 

(ii)               I₂ and CCl₄

6.      K_H value for Ar_(g) CO2_(g), HCHO_(g), and CH_4(g)  are 40.39, 1.67, 1.83 X 10^-5, 0.413 respectively.  Arrange these gases in the order of their increasing solubility.

(1)   HCHO < CH₄<CO₂<Ar

7.       Why is the vapour pressure of an aqueous solution of glucose lower than that of water?

8.      Differentiate between molarity and molality.  Explain the effect of temperature on it with reason.

9.      H₂S a toxic gas with rotten egg like smell is used for the qualitative analysis.  If the solubility of H₂S in water at STP is 0.195 mol Kg ^-1.  Calculate Henry`s law constant.

10.  A solution of glucose in water is labelled as 10% (by mass).  What would be the molality and the molarity of the solutions?

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DATE OF SUBMISSION: JUNE SECOND WEEK

1.       Which point defect of its crystal decreases the density of a solid?

2.       Explain the differences between metallic and ionic crystals in their conductivity               

3.     How may the conductivity of an intrinsic semiconductor be increased?

4.   What are n type semi-conductors?

5.   Account for the following

     (a)         Schottky defect lower the density of related solids

     (b)        Conductivity of silicon increases on doping it with phosphorous.

6.        Why does the presence of excess of Lithium makes LiCl crystal pink?

7.      What change occurs when AgCl is doped with CdCl2?

8.     What type of semiconductor is produced when silicon is doped with Boron

9.      How you can determine  the atomic mass of an unknown metal if you know its                         mass,density and the dimensions of the unit cell of its crystal.

10. All text questions in the text book.

DATE OF SUBMISSION: JUNE FIRST WEEK

1.           Find out the number of atoms per unit cell in afcc structure having only single atoms at its lattice points.

2.     Silver crystallises in afcc lattice .edge length of the unit cell is 4.077X 10 -8cm and its density is 10.5 g/cm3.Calculate the atomic mass of silver.

 3. Iron has a bcc unit cell with a cell edge of 286.65 pm.The density of Iron is 7.87g/cm3. Use this information to calculate Avogadro number. Atomic mass of Iron is 56g/mole.

4. Silver has atomic mass 108 amu,density 10.5g/cm3.If the edge length of the unit cell is 409 pm calculate the radius of an atom of silver.

5.Calculate the packing efficiency of a metallic crystal for a simple cubic lattice.

6.How you can determine Explain the atomic mass of an unknown metal if you know its mass,density and the dimensions of the unit cell of its crystal. 

7.Cu crystallises with fcc unit cell. If the radius of copper atom is 127.8pm, calculate the density of copper metal. Atomic mass of copper is 63.54

8.        Aluminiumcrystallises in fcc structure. Atomic radius of the metal is 125pm.What is the length of the  side of the unitcell of the metal.

9.        A solid with cubic crystal is made of two elements P and Q. Atoms of Q are at the corners of the   cube and P atoms at the body centre. What is the formula of the compound?