Physical Chemistry Answers

The potential density D is defined as the density that air would attain if it was adiabatically transformed to a pressure p=1000 mbar.
a)Show that D=density(p/P)^Cv/Cp
b)Calculate D for a sample of air with pressure 600 mbar and temperature -15 degree centigrade.
c) Show that (dD/dz)/D=-1/T(g/Cp+dT/dz)

I have a question regarding the following problem:

AgBr is used in black and white photographic film.
The reaction is: 2AgBr +2 photons 2Ag(s) +Br2(l), with Ag forming the dark image
The more photons absorbed, the darker the image.
(a) If 200 kJ per mol of Ag is needed for this photochemical process, what is
the longest wavelength of light needed to provide this energy?
(b) Explain why this film can be handled in a darkroom under red

For a, I got "497.25 * 10^ (-33) nm" but I'm not sure if it's right, and for b, I concluded that the energy absorbed by photons when impacted by red light is 313*10^(-21) which is much lower than the energy needed for the reaction, so is my answer wrong? I would deeply appreciate it if you could help me with this problem. Thank you very much!

the dissociation of water at a certain temperature is 1.9*10power-7 percent and the density of water is 1.0 g/cmcube the ionisation constant of water is

If the caffeine concentration in a particular brand of soda is 1.83 mg/oz,
drinking how many cans of soda would be lethal? Assume that 10.0 g of caffeine is a lethal dose, and there are 12 oz in a can.

Explain the effect of (i) increase in pressure and
(ii) increase in temperature on the following
reaction :
N2(g) + 3 H2(g) ⇌ 2 NH3(g), ΔrH° = - 92.2 kJ mol-1

1.33 dm3 9f H2O at 70°C are saturated by 2.25 moles of Pb(NO3)2 and 1.3 dm3 of H2O at 18°C are saturated by 0.53 moles of the same salt .if 4.50 dm3 of the saturated solution are cooled from 75- 18 °C , calculate the amount of solute deposited in moles and gram

Convert 0.5599 moles of Lead nitrate to gram

Two electrolytic cells were connected in series.
In one (i) an AgNO3solution and in the other
(ii) 500 cm3of a solution in which 10.0 g of
CuSO4. 5 H2O is dissolved are present. After
passing electric current for 30 minutes, it was
found that 1.307 g silver has been deposited.
Calculate the concentration of copper expressed
in gram per litre (gL-1) in the copper sulphate
solution after the electrolysis.
[Atomic masses are : Cu = 63.54; Ag = 108]

2.0 g of benzoic acid dissolved in 25.0 g of
benzene shows a depression in freezing point
equal to 1.62 K. What is the percentage
association of benzoic acid ? Kf for benzene is
4.9 K kg mol-1.