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Recalling what we learned in Chapter 3, when an acid and a base are combined, there is a neutralization reaction. When this takes place the chemical reaction forms two new chemical compounds, salt and water.
STOMACH
Cells in the stomach release hydrochloric acid. Hydrochloric acid is so strong that it can eat the lining of your digestive tract. To prevent this, mucous is released by cells, adhering to the stomach walls. The mucous is a base that neutralizes the acid and prevents the stomach from digesting itself.
PANCREAS
The pancreas produces sodium bicarbonate solution that is dumped into the small intestine.
INTESTINES
The acidic food leaves the stomach and enters the small intestine. Here is where the sodium bicarbonate from the pancreas and from the cells in the small intestine neutralizes the acid.
Equation of what happens during the neutralization reaction in the digestive system.
HCl(aq) + NaHCO3(aq) →NaCl(aq) + H20(l) + CO2(g)
hydrochloric acid + sodium bicarbonate → sodium chloride + water + carbon dioxide
Acids and Bases in the Environment
Acids and Bases in the Environment
When lakes contain too much acid, natural limestone (Calcium Carbonate - CaCO3(s)) is used to neutralize the water that has been acidified by precipitation. This is called liming. This happens because the calcium carbonate raises the pH of the water.
This is not a permanent solution. Why do you think this is a temporary fix?
H2SO4(aq) + CaCO3(s) →CaSO4(s) + CO2(g) + H20(l)
sulfuric acid + solid calcium carbonate → solid calcium sulfate + carbon dioxide gas + water
Reducing Emissions
Reducing Emissions
We understand that liming is not a permanent solution because we have forms of precipitation throughout the year. As long as we have acid rain, there will always be acid deposition. One way to reduce the amount of sulfur dioxide that gets released into the atmosphere is to reduce products that require combustion. For example, natural gas. It is possible to remove the sulfur from fuels before they are burned.
Most people do not get the opportunity to see the full process of refining crude oil. This video that was developed by Flint Hills Resources will help us get a better idea.
FYI
Crude oil is made up of decomposed dinosaurs → T/F
It was formed in marine environments a long time ago by dead algae and zooplankton.
These organisms absorbed energy from the sun and stored it as carbon molecules within their bodies. Once they died, their remains sunk to the bottom of bodies of water and were buried into layers of sand, mud, and rock.
With all the pressure, high temperatures, and lack of oxygen, the organic material turned into a waxy substance called kerogen. Eventually the kerogen transforms into hydrocarbons. Although hydrocarbons to occur naturally in nature, the refining of these hydrocarbons produces various types of fuels and useful products. The big concern is with combustion of these fuels. When the hydrocarbons react with other chemicals, carbon dioxide is produced.
Example: Combustion of methane
CH4 + 2O2 → CO2 + 2H2O
methane + oxygen → carbon dioxide + water
Facts about crude oil
How deep underground is crude oil?
1949 → 3,500 feet
2008 → 6,000 feet
Current → 40,000 feet
Mount Everest is only 29,032 feet.
Two ways to reduce emission in the oil and gas industry are by removing the sulfur before it is sent to consumers and by sulfur scrubbing. Coal combustion accounts for 40% of the worlds energy production which makes it a leading contributor to climate change. As a way to help reduce these emissions, many coal generating plants and other coal burning industrial plants have added sulfur scrubbers to their smokestacks form of energy that is produced in Canada and other parts of the world. This is not a permanent solution, so our government wants to reduce emissions of coal energy generation by phasing out these plants by 2030.
Check for Understanding
Write out the general chemical equation for a neutralization chemical reaction.
Describe how driving a car contributes to the problem of acid precipitation.
Explain how liming can raise the pH of a lake affected by acid precipitation.
Why is it important to remove sulfur from coal and natural gas before they are burned?
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