Question

An amount of 1.75*10-4 mole of HI decomposes by the absorption of photons of wavelength 2500 angstorm.,If one molecules decomposed Per absorbed Photon ,the total energy absorbed us???(NA×hc)=0.12





Guys Pls solve

Answer 1

Therefore total energy absorbed is 84 J (approx.)

Given : An amount of 1.75 × 10¯⁴ mole of HI decomposes by the absorption of photons of wavelength 2500 Å.

To find : If one molecule decomposed per absorbed photon, the total energy absorbed.

Solution : number of decomposed HI molecules in 1.75 × 10¯⁴ mole, N = 1.75 × 10¯⁴ × Avogadro's number

= 1.75 × 10¯⁴ × 6.023 × 10²³

= 1.054 × 10^20

so, no of absorbed HI molecules = 1.054 × 10^20

wavelength of absorbed photons , λ = 2500 Å

= 2.5 × 10^-7 m

now energy of each photon, E = hc/λ

= (6.63 × 10^-34 × 3 × 10^8)/(2.5 × 10^-7)

= (6.63 × 3/2.5) × 10^-19

= 7.956 × 10^-19 J

so total energy absorbed = 1.054 × 10^20 × 7.956 × 10^-19

= 10.54 × 7.956 = 83.85624 ≈ 84 J

Therefore total energy absorbed is 84 J (approx)