Silver crystallizes in face-centred cubic unit cell. Each side of this unit cell has a length of 400 pm. Calculate the radius of the silver atom.

(Assume the atoms just touch each other on the diagonal across the face of the unit cell. That is each face atom is touching the four comer atoms)

Describe what you understand by primary structure and secondary structure of proteins.

Mention two important uses of each of the following:

(i) Bakelite

(ii) Nylon6

Nitrogen pentoxide decomposes according to equation:

2N₂O₅ (g) → 4NO₂ (g) + O₂ (g)

This first order reaction was allowed to proceed at 40 °C and the data below were collected:

(a) Calculate the rate constant. Include units with your answer.

(b) What will be the concentration of N₂O₅ after 100 minutes?

(c) Calculate the initial rate of reaction.

Explain how the phenomenon of adsorption finds application in each of the following processes:

(i) Production of vacuum

(ii) Heterogeneous catalysis

(iii) Froth Floatation process

OR

Define each of the following terms:

(i) Micelles

(ii) Peptization

(iii) Desorption