Question

Question 2 1 pts In your own words, explain how Transition lenses are an example of Le Chatelier's principle. In your answer, address: a. What is being added or removed? b. Is it a product or reactant in the chemical reaction? How does this relate to Le Chatelier's principle? c. How does this effect the color of the lenses? Canvas will probably autograde this as incorrect, but I plan to read your explanations and give you 0, 1, or 2 points. Maybe you'll even get 3 points if you do an EXCELLENT job. BILA. A. I E 1. Eelv e a HTML Editoria X E 12pt Paragra

Answer 1

Let me explain what is meant by Le Chatelier's Principle first, it states that-

A principle stating that if a constraint (such as a change in pressure, temperature, or concentration of a reactant) is applied to a system in equilibrium, the equilibrium will shift so as to tend to counteract the effect of the constraint.

Foe example, let's suppose if I dump snow on my neighbor’s driveway, and he dumps snow from his driveway onto mine at the same rate. A plane’s passengers flying over us will simply see an unchanging white driveway.

If I suddenly had trouble picking up the snow while my neighbor proceeded as normal, the snow would suddenly pile up on my side. The plane passengers would see the asphalt on the neighbor’s driveway.

There’s no system trying to “reorder things” or “offset anything” (even if we consider the natural snow is still falling), it’s simply the case of a hampered reverse reaction that does not keep up and maintain the original equilibrium.

Transition lenses are the best type of photochromatic lenses which most of us have used or seen in our daily life.

In the presence of UV-A light (wavelengths of 320–400 nm), electrons from the glass combine with the colorless silver cations to form elemental silver. Because elemental silver is visible, the lenses appear darker.

a) Photochromic lenses have millions of molecules of substances such as silver chloride or silver halide embedded in them. The molecules are transparent to visible light in the absence of UV light, which is normal for artificial lighting. But when exposed to UV rays, as in direct sunlight, the molecules undergo a chemical process that causes them to change shape. The new molecular structure absorbs portions of the visible light, causing the lenses to darken. The number of molecules that change shape varies with the intensity of the UV rays.

${\displaystyle {\ce {Cl- -> Cl + e-}}}$

${\displaystyle {\ce {Ag+ + e- -> Ag}}}$

When we go indoors and out of the UV light, a different chemical reaction takes place. The absence of the UV radiation causes the molecules to "snap back" to their original shape, resulting in the loss of their light absorbing properties. In both directions, the entire process happens very rapidly.Back in the shade, this reaction is reversed. The silver returns to its original ionic state, and the lenses become clear.

${\displaystyle {\ce {Cu^2+ + Ag -> Cu+ + Ag+}}}$

B and C) If we see in terms of the transition lens, then it is clearly the product or non-ionic silver that is causing the lens to become darker when in the direct contact of UV rays.

Clearly, according to the principle , a constraint (change in temperature) is applied to the otherwise stable system which results in the increased rate of the forward reaction and a reduced rate of the backward reaction; and once we come back out of the sunlight, the rate of reverse reaction increases comparatively. Hence, it is a perfect example of Le Chatelier's Principle.