Answer : The enthalpy change of reaction is -23.9 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The given final reaction is,
The intermediate balanced chemical reaction will be,
(1)
(2)
First we will reverse the reaction 1 and multiply equation 2 by 3 then adding both the equation, we get :
(1)
(2)
The expression for final enthalpy is,
Therefore, the enthalpy change of reaction is -23.9 kJ
Answer:
a) excitation radiation
Explanation:
the fluorescence quantum efficiency of the fluorescing molecule:
Molecular structure and its chemical environment influence whether a substance will fluoresce and the intensities of these emissions. The quantum yield or quantum efficiency is used to measure the probability that a molecule will fluoresce or phosphoresce. For fluorescence and phosphorescence is the ratio of the number of molecules that luminescent to the total number of excited molecules. For highly fluoresce molecules, the quantum efficiency approaches to one.Molecules that do not fluoresce have quantum efficiencies that approach to zero.
the molar mass of the compound
Influence of a halogen substitution decreases fluorescence as the molar mass of the halogen increases. This is an example of the “heavy atom effect” which suggest that the probability of intersystem crossing increases as the size of the molecule increases. As the molar mass of the substituted compound increases, the relative intensity of the fluorescence decreases.
The absorptivity of the compound
he molar absorptivity, which measures the probability that a transition will occur
JJ Thomson discovered the electron :)
Answer:
C
Explanation:
Neon is a noble gas, which is monoatomic.