Question

Determine total energy of 1 mol of photons in J/mol having λ = 600 nm 

Given h = 6.62 × 10^-34J-sec, c = 3 x 10⁸ ms¹

(1) 1.99 × 10⁵ J/mol 

(2) 6.64 x 10⁸ J/mol 

(3) 1.24 × 10⁴ J/mol

(4) 1.24 × 10⁸ J/mol

Answer 1

Correct option is (1) 1.99 x 10⁵ J/mol

\(E_T = \frac{N_AhC}{\lambda}\)

\(E_T = \frac{6.02 \times 10^{23}\times 6.62 \times 10^{-34}\times 3 \times 10^8}{600\times 10^4}\)

\(= \frac{119.56 \times 10^{-3}}{600\times 10^{-9}}\)

\(= 19.93 \times 10^4J/mol\)

or 1.99 x 10⁵ J/mol