Question

Calculate energy of one mole of photons of radiation whose frequency as 5 $\times$ ${10}^{14}$Hz.

• A. 199.51 KJ
• B. 299.31 KJ
• C. 399.31 KJ
• D. 499.31 KJ

Answer 1

Answer: (A)

Step 1:

As we know, 1 mole = 6.022 $\times$ ${10}^{23}$ atoms

h = Planck's constant = $6.626\times {10}^{34}Js$

Frequency = $v=5\times {10}^{14}{s}^{-1}$

Step 2:

Now the energy of a single photon, $E=h\nu$
= $6.626\times {10}^{-34}Js\times 5\times {10}^{14}{s}^{-1}$

= (3.313 $\times$ ${10}^{-19}J$)

Step 3:

Energy of one mole of photon is $E\times A$

= (3.313 $\times$ ${10}^{-19}$ J)(6.022 $\times$ ${10}^{23}$ ${mol}^{-1}$)

= 199.51 kJ ${mol}^{-1}$

Hence, option (B) is correct.