Answer:

Explanation:
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In this case, according to the given information, it turns out firstly necessary to write out the described chemical reaction as shown below:

Now, we set up the expression for the calculation of the standard free energy change, considering the free energy of formation of each species, specially those of H2 and F2 which are both 0 because they are pure elements:

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Answer:
three valence electrons
Explanation:
Gallium has three electrons in the outer energy level and therefore has three valence electrons. The identification of valence electrons is vital because the chemical behavior of an element is determined primarily by the arrangement of the electrons in the valence shell.
What is the empirical formula for ribose (C5H10O5)?
C. CH20
Explanation:

The maximum wavelength of light that can cause this reaction is 420 nm.
a) The wavelength given lies in the range of visible light range that is from 400 nano meters to 700 nano meters.
The light with wavelength of 420 nm is found in the range of visible light.
b)The maximum strength of a bond :

where,
E = energy of photon = Energy required to break single molecule of nitrogen dioxide
h = Planck's constant = 
c = speed of light = 
= wavelength = 


Energy required to break 1 mole of nitrogen dioxide molecules:


(1 J = 0.001 kJ )
285.13 is the maximum strength of a bond, in kJ/mol, that can be broken by absorption of a photon of 420-nm light.
c) the photodissociation reaction showing Lewis-dot structures is given in an image attached.