7.00ml ampule of a 0.150 mole solution naphthalene in hexane is excited with a flash of light. the naphthalene emits 19.9j of energy at an average wavelength of 349 nmmi. what percentage of naphthalene molecules emitted a photon?

Mole of naphthalene solution = 0.150

Molecules of naphthalene in the solution = 0.150 mol x (6.022 x 10²² molecules/1 mol) = 9.033 x 10²² molecules

Energy of a photon,

E = hγ = h. c/λ

where h is Planck's constant (6.626 x 10⁻³⁴) and γ is the frequency of light, c is the speed of light (3 x 10⁸) and is the λ wavelength of light.

Given, wavelength of light = 349 nm = 349 x 10⁻⁹ m ( 1 nm = 10⁻⁹ m)

Energy of one photon is,

E = 6.626 x 10⁻³⁴Js x (3 x 10⁸ms⁻¹ / 349 x 10⁻⁹ m)

E =  5.7 x 10⁻¹⁹ J

Energy emitted by naphthalene = 19.9 J

Therefore, the number of photons emitted = 19.9 J / 5.7 x 10⁻¹⁹ J = 3.5 x 10¹⁹

Percentage of naphthalene molecules that emitted a photon is

(photons emitted / total number of naphthalene) x 100

(3.5 x 10¹⁹/ 9.033 x 10²²) x 100

0.0387%

Thus 0.0387% naphthalene molecules emitted a photon.

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation:

warm front forms when a moist, warm air mass slides up and over a cold air mass. as the warm air mass rises, it condenses into a broad area of clouds. a warm front brings gentle rain or light snow, followed by warmer, milder weather.

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