An isolated atom of a certain element emits light of wavelength 655 nm when the atom falls from its fifth excited state into its second excited state. The atom emits a photon of wavelength 435 nm when it drops from its sixth excited state into its second excited state. Find the wavelength of the light radiated when the atom makes a transition from its sixth to its fifth excited state.

Explanation:

From the question we are told that

Light wavelength  

Light wavelength atom fall

Photon wavelength  

Photon wavelength atom fall

Generally the equation for the reciprocal of wavelength of emitted photon is is mathematically given by

Therefore for initial drop of 5th to 2nd

Therefore for initial drop of 6th to 2nd

Generally we subtract (5th to 2nd) from (6th to 2nd)

Therefore for 6th to 5th stage is mathematically given by

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.