Physical Chemistry Answers

Docosanol is the generic name for the drug Abreva which is used to treat cold sores. It
was found to be 80.90% carbon, 4.899% oxygen, and the rest was hydrogen. If the
molecular mass of docosanol is 326.6 amu, what is the molecular formula of docosanol?

A foolish boy remove a nail from a vertical wall by pulling a stick attached to the nail in a direction 30 deg to the wall.
if the tension in the stick is 10cm , calculate the magnitude of the force wich is not effective in pulling out the nail, is it possible to remove the nali thos way if minimum force required is 7N?
why is the boy foolish?

Why PV^gamma= constant

A sample of 2,4-hexadiene in methanol in a 2.5 cm cell shows an
absorbance of 0.65 at 240.0 nm. What is the concentration of the
diene? The molar absorption at this wavelength is 12100 dm3 mol1
cm1
.

How is the rate of a chemical reaction expressed? Explain giving a suitable
example.

The vapour pressures of pure liquids . A and B at 300 K are 4.5×10⁴ Pa and 6.5× 10⁴ Pa respectively. calculate the mole fractions of of A and B in vapour and liquid phases of a solution when the liquid equilibrium total vapour pressure of the binary liquid solution is 5.5× 10⁴ Pa at 300 K . Assume that the liquid and the vapour are ideal .

Give the dispersed phase and the dispersion medium for the following :

(i) Smoke
(ii) Cream
(iii) Mist

What are pseudo first order reactions ? Give one example of such a reaction. Also write the expressions for the pseudo first order rate constant.

For the reaction ,

2NO₂ (ɡ) ⇌N₂O₄ (ɡ)
Kp is 7.14× 10⁻⁵ Pa at 303 K . Find Kc at this temperature.

Sodium metal crystallises in a body centered cubic lattice with a cell age of 425 pm . Calculate the density of the metal.