Question

calculate the energy of kilocalorie per mole of the photon of an electromagnetic radiation of wavelength 5700 angstrom
​

Answer 1

$\huge {\mathcal{\purple{A}\green{N}\pink{S}\blue{W}\purple{E}\green{R}\pink{!}}}$

λ=7600

A

˚

=7600×10

−8

cm

c=3×10

10

cms

−1

Frequency, v=

λ

c

=

7600×10

−8

3×10

10

=3.947×10

14

s

−1

Energy of one photon =hv=6.62×10

−27

×3.947×10

14

=2.61×10

−12

erg

Energy of one mole of photons =2.61×10

−12

×6.02×10

23

Energy of one mole of photons =2.61×10

−12

×6.02×10

23

=15.71×10

11

erg

Energy of one mole of photons in kilocalorie =

4.185×10

10

15.71×10

11

[1kcal=4.185×10

10

erg]

=37.538 kcal per mol.