Chemistry question?

#O_3# (g) #-># #O_2#(g) + O(g)

O(g) = 247.5 kj/mol
O2(g) = 0
O3(g) = 142.3 kj/mol

What is the maximum wavelength of a photon can have if it is to possess sufficient energy to cause this dissociation? In what portion of the spectrum does this wavelength occur?

1 Answer
Nov 18, 2017

The maximum wavelength of a photon capable of expressing the energy required for that reaction is #1.890nm#.

Explanation:

I will assume "energy" you refer to is heat for this problem.

#DeltaH^0 = (247.5"kJ") - (142.3"kJ") = +105.2"kJ"#

#if E = hnu#
#and c = lambda nu#

#=> E = (hc)/lambda#

#105.2 * 10^3 "J" = (6.626*10^-34"kg" * "m"^2)/"s"^2*(3.00*10^8"m")/"s" * "J"/(("kg" * "m"^2)/("s"^2))/lambda#

#therefore lambda approx 1.890*10^-30"m" * ("nm")/(10^-9"m") = 1.890 "nm"#

The units all work out, units are really important in chemistry and physics, losing track usually is anticipated and these answers are placed on exams to trick you.