No, the elements are not always transparent.
<u>Explanation:</u>
The elements become transparent when the light passes through those elements. Transparency is caused because of the transmission and the passing of the light waves through these elements.
But the metals do not become transparent even when the light waves pass through these metals. Metals do not become transparent because the refractive index in them is very big.
When waters salinity increases it’s freezing point will decrease. This is one of the reasons why people salt the roads after a snow storm.
First, we need to get the value of Ka:
when Ka = Kw / Kb
we have Kb = 1.8 x 10^-5
and Kw = 3.99 x 10^-16 so, by substitution:
Ka = (3.99 x 10^-16) / (1.8 x 10^-5) = 2.2 x 10^-11
by using the ICE table :
NH4+ + H2O →NH3 + H+
intial 0.013 0 0
change -X +X +X
Equ (0.013-X) X X
when Ka = [NH3][H+] / [NH4+]
by substitution:
2.2 x 10^-11 = X^2 / (0.013 - X) by solving this equation for X
∴X = 5.35 x 10^-7
∴[H+] = X = 5.35 x 10^-7
∴PH = - ㏒[H+]
= -㏒(5.35 x 10^-7)
= 6.27
There can only be two electrons in the innermost shell of an atom so b is the correct answer
The answer is A
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