Final Exam

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Chemistry

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University of California San Diego

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Chem 311

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Final Exam, CHEM 311/Spring 2022 (70pts)

Name:………………………………………

1. Fully explain, ocean acidification and how you propose to control ocean acidification.

(Illustration will help)

Ocean acidification is a process of the reduction of the pH of the ocean over a given period of time due

owed primarily to the uptake of atmospheric carbon dioxide. The dissolved carbon dioxide will react

with water in the ocean to form carbonic acid, which is of course an acid hence lowering the ocean’s pH.

The ocean is originally slightly basic with a pH of 8.2 hence converting it to a more acidic environment

will entail a lot of consequences for the organisms who were used to the alkaline environment of the

ocean. The chemical reaction associated with this is illustrated below:

2 (g)

+ H

(l)

---------> H

(aq)

Carbon dioxide water carbonic acid

The most common source of atmospheric CO2 is due to fossil fuel emissions. Fossil fuel emissions

account for majority of the world’s energy source i.e., for electricity. The most effective way to control

ocean acidification would be to lessen the emission of fossil fuels however this proposal would require

imposing government regulations and incentives for industries to reduce or stop using fossil fuels and

instead rely on renewable sources of energy such as solar or wind energy. Fortunately, as a non-

renewable energy source, the supply of fossil fuels is limited and in the future the world will be more

reliable on non-renewable sources however there is still some time before the fossil fuels are used up

and this timeframe could worsen ocean acidification hence we should still be more proactive in reducing

fossil fuel emission.

Another idea would be the remove the CO

from the ocean itself, one idea would be to react carbonic

acid with calcium to form calcium carbonate

(aq)

+ Ca

(aq)

-------> CaCO

3(s)

Carbonic acid calcium calcium carbonate

Another idea is to promote ocean fertilization since some ocean organisms use carbon dioxide in

photosynthetic processes. There is also a new technology called direct ocean capture (DOC) where they

use machines to extract CO2 directly from the atmosphere and the ocean and move it to underground

storage facilities where it can be used for other purposes.

2. How will you extract gold from cell phones? What are your novel ideas to recycle cellphones and

other electronics?

The idea behind these processes is to recycle gold from electronic equipment as a large portion

of gold that we have extracted is now embedded within the very electronics we use. With these

methods of gold recycling, we can essentially utilize the waste/leftover material we have from

the electronics we have discarded and make new material at a lower cost.

Gold can be extracted from old pieces of electronics via multiple novel methods. The

most recent idea is to utilize metallophage bacteria to directly absorb and extract gold from

electronic equipment. The bacteria responsible is named Cupriavidus metallidurans and it

ingests toxic metals while still being able to thrive and when it ingests gold it produces tiny gold

pieces. However other ideas such as chemical pretreatment followed by leaching is being

investigated as more novel ideas of recycling gold from electronic equipment. In any case the

idea is to create a cost-effective way of extracting gold from electronics that represents a

cleaner cheaper and easier solution to simply mining gold from the earth. The use of bacteria

seems like an organic way of recycling hence more research should be done on optimizing this

method. To recycle old phones and electronics, we don’t need to focus on gold alone. Old

electronics can be broken apart and the obtained iron, steel, and aluminum can be recycled as

pellets of metal and can be sold to companies that manufacture wires, cables, and other pieces

for new electronics. They can also be used in constructing buildings and machinery.

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Final Exam, CHEM 311/Spring 2022 (70pts) Name:……………………………………… 1. Fully explain, ocean acidification and how you propose to control ocean acidification. (Illustration will help) Ocean acidification is a process of the reduction of the pH of the ocean over a given period of time due owed primarily to the uptake of atmospheric carbon dioxide. The dissolved carbon dioxide will react with water in the ocean to form carbonic acid, which is of course an acid hence lowering the ocean’s pH. The ocean is originally slightly basic with a pH of 8.2 hence converting it to a more acidic environment will entail a lot of consequences for the organisms who were used to the alkaline environment of the ocean. The chemical reaction associated with this is illustrated below: CO2 (g) + H2O (l) ---------> H2CO3 (aq) Carbon dioxide water carbonic acid The most common sourc ...
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