CHEM 106

Last class, we learned about the body’s carbonic acid-bicarbonate buffer system, which stabilizes the pH of our blood. When this system is overwhelmed, the blood can become either too acidic (this is called acidosis) or too basic (this is called alkalosis).

Blood becomes more acidic when the body can’t get rid of enough CO2, for example when breathing is impaired. “As blood pH drops, the parts of the brain that regulate breathing are stimulated to produce faster and deeper breathing” to expel more CO2 from the body. Acid in the body can also suddenly increase if one ingests a “substance that is, or can be broken down (metabolized) to, an acid”–substances like antifreeze and aspirin (in high doses).

Alkalosis, on the other hand, occurs when the blood pH is too high. This can happen “during periods of prolonged vomiting,” or “in a person who has ingested too much base from substances such as baking soda.” Rapid breathing (hyperventilation) can also decrease blood pH, by removing too much CO2 from the bloodstream. Alkalosis can be treated with water and electrolytes, slow breathing or, if severe, with injections of diluted acid. Also, “breathing into a paper (not a plastic) bag may help raise the carbon dioxide level in the blood as the person breathes carbon dioxide back in after breathing it out.”

This week in class we focused on acids and bases, doing so made me think of the term “lactic acid”. For my high school varsity crew team, I had to have my lactic acid threshold tested in order to learn what heart rate I should maintain when doing a low-cardio workout versus during a high-cardio workout. In order to test these levels, I was told to row on the ergometer, or “rowing machine”, for certain amounts of time at a range of different rates. Immediately after I finished each rate, blood was taken from my ear and its lactic acid levels were tested. Though I was familiar with the term “lactic acid”, I never understood the science behind it. I decided to do a little bit of research in order to discover how my lactic acid testing related back to the concepts that we learned in class.
Lactic acid is naturally created in the body. The lactic acid test measures the level of lactic acid made by muscle tissue and red blood cells. During strenuous exercise, the body does not receive enough oxygen to generate energy aerobically, thus it must resort to generating it anaerobically. Through glycolysis, the body metabolizes glucose into pyruvate. With abundant oxygen at hand, the body transfers the pyruvate to an aerobic pathway to continue breaking it down and producing energy. In contrast, when the body does not receive enough oxygen, it converts the pyruvate into the negatively charged ion lactate, and produces H+ ions. This allows glucose breakdown- anaerobic energy production- to continue. However, the body can’t maintain this energy production for long. As lactate levels rise, the muscles become acidic- a condition that reduces the production of energy from glucose. Thus, the body is forced to slow down, in turn preventing potential muscle damage from occurring. When the body slows down it is able to receive more oxygen, and is able to convert the lactate back to pyruvate, which can then be aerobically metabolized.

As we learned in the Acid-Base Crash Course, acids are sour to taste, like vinegar.  We have learned drinking lemon juice is not harmful for our bodies, but this has lead me to think, is drinking other, more concentrated acids harmful to our bodies, or could there be health benefits?  And what about doing the same with Bases?

I took this question to google where I found an article written by Dr. Oz in response to a question submitted to Oprah.  In Dr. Oz’s response, he encouraged the viewer that consuming an ounce of vinegar per day could have health benefits, if nothing less than to reduce appetite

On the other end, Mark Sircus, a Doctur who focuses much of his research on the benefits of Baking Soda on our health, has conducted much research on Sodium Bicarbonate’s effects on cancer and kidney disease.  He is the sole Dr. who has written a book in support of this ‘cure.’  Dr. Sircus believes that ‘people have become acidic’ and that pH medicine must be a key element in future elements.  Thus ‘bicarbonate’ has many healthy properties such as reducing tumor size and controlling the overall growing acidity of humans.  To support Sircus’ claims, he calls upon doctors efforts to use sodium bicarbonate in chemotherapy as it helps ‘detoxify and buffer’ and neutralize.

Dr Oz article: http://www.oprah.com/own-ask-oprahs-all-stars/Ask-Oprahs-All-Stars-Is-This-Normal_1 

Dr. Sircus’ Thoughts: https://www.youtube.com/watch?v=ORa0OybvK90

As an Art History major, you are forced to endure “discussion”, a third meeting every week when you go over what you learned in lecture during ARTH100. Every now and then, after meeting in Davis 212, a small classroom adjacent to the Davis Museum, you are forced to enter the gallery and look at objects with your class. I am honestly being dramatic right now, it just kind of sucks to show up that extra third time; but overall, the experience is very enjoyable.

Inevitably, one of the objects you discuss is the Wellesley Athlete. It’s the department’s introduction to a lively debate in art historical methods still active today regarding how objects should be experienced. It is the museum’s way to take works of art usually experienced as pieces in the home or objects their owners handle or alter and transform them into objects museum visitors do not interact with and can only look upon, thereby making them inert. The museum cuts short the objects evolution as a piece in the real world interacting with the culture it is a part of in order to preserve it for future generations.

One such object is the Wellesley Athlete. This piece, believed to be a Roman copy, was originally meant to be viewed in a garden setting. Today, it sits on a pedestal in the middle of the the Davis Museum. When we study the object, we are asked to imagine what it must have been like to see the object in its intended space and how its current setting alters the objects effect. Then we are asked to consider why the piece is kept indoors. Most of us have the wits to understand that if we were to leave the object outside it would be damaged- either due to erosion or acid rain or freak accidents. However, we never really talked about the chemistry to acid rain. And I didn’t really understand it until I saw this weeks video.

Marble, the rock type the Wellesley Athlete was carved from, is metamorphosed limestone. In this week’s Crash Course, our host went into detail about how acid rain affects limestone. After explaining how acid rain is produced -after coal is burned for fuel and sulfur is realeased- he explained how acid rain develops and interacts with limestone. In his video, he said-

When coal is burned, the sulfur in it reacts with oxygen to form sulfur dioxide. Sulfur dioxide reacts with water and oxygen in the air to form sulfuric acid. When the sulfuric acid rains down a set of acid base reactions takes place that damage limestone.

I am definitely paraphrasing here, but that explains the gist of it and why acid rain sucks.

The article that I read about acid rain showed the connection between chemistry, biology, and environmental science. It also connected to a class that I took last spring, called Coastal Zone Management, which I really enjoyed. The story of how acid rain has turned a lake into a gelatinous substance goes as follows:

1. Nickel mining resulted in acid rain, which resulted in the removal of calcium from soil in important areas for watershed.

2. Without calcium, the Daphnia plankton species could not build their exoskeleton.

3. The Holopedium plankton species started to take over the Canadian lakes, as they need less calcium from their environment to create their exoskeleton.

4.  Holopedium plankton repel predators by producing a gel that repels predators. This gel thickened the water in certain areas.

So how was the environment affected?

1. Clogged filtration systems

2. Population damage to larger animals

3. A change in the balance of nutrients in the water system

What is the outcome?

It could take thousands of years for the watershed areas to get the calcium they lost naturally. Though acid rain has stopped, recovery will be long and the lakes have been “pushed into an entirely new ecological state.”

http://www.citylab.com/weather/2014/11/acid-rain-has-turned-canadian-lakes-into-a-kind-of-jelly/382922/

In a Smithsonian article by Devin Powell, the discovery of vanillin in rock in Northern Italy. The rock contains important information about soils from hundreds of millions of years ago. As the name suggests, vanillin, an organic compound, is molecularly very similar to vanilla, a common spice and flavoring that we use today. The vanillin in the soil is rare, because normally after 250 million years, bacteria would have consumed it, leaving no traces. So why does the vanillin remain?

Interestingly, the scientists utilized the dairy industry to figure this out. Apparently, vanilla is often used to enhance the flavor of milk, but the only way to retain that flavor is to lower the pH, or acidify, the milk. While this sheds a somewhat disturbing light on how much staple food items are altered during production, it also provides an interesting (possible) explanation as to why the vanillin has remained in the rock for over 250 million years. The soil must have been much more acidic than normal, indicating that some kind of acid rain or acidic substance was naturally added to the soil, through precipitation or possibly volcanic eruption.

As we already know, vast decreases in pH in soil can be destructive to vegetation and animals throughout the trophic levels. Though the scientists do not yet know what exactly caused the acidification of the soil and how widespread the damage was, the vanillin provides important clues for what to look for in other areas of the world.

http://www.adventurewomen.com/blog/article/11-places-to-see-before-the-disappear-taj-mahal/http://blog.travelworldpassport.com/taj-mahal-a-marble-mausoleum-for-the-love-of-life/

I found the video on the impact of acid-base reactions particularly on statues very interesting. It was surprising to hear that water in it’s neutrality can act as an acid or a base, by either donating or accepting a proton. This is what forms the base of acid rain reactions that then affect multiple historic monuments and statues.
One example that I have always heard about it the transformation of the Taj Mahal over the years due to acid rain. As we now acid rain is formed by the reaction of sulfur dioxide, nitric oxide and carbon dioxide with pure water (pH 7) to form acid rain (pH < 5.6). The effects on acid rain on monuments made of marble and limestone are detrimental. The Taj Mahal composed entirely out of marble (a sign of affection and purity by Emperor Shah Jahan for his wife Mumtaz) has been a major victim to this naturally occurring phenomenon.
As we can see from the pictures above, over the years the pristine bone white structure has been tainted a nasty yellow due to the occurance of acid rain. Marble, just like limestone, consists of calcium carbonate (CaCO3) which is highly reactive when it comes with contact with sulfuric acid (the primary component of acid rain).

CaCO3 + H2SO4(aq) = Ca2+(aq) + SO2-4(aq) + H2O + CO2

Marble which is made up off large crystals and porous in nature is highly responsive to the sulfuric acid ions. When a solution of sulfuric acid and water falls on marble, it forms a solution containing calcium and sulfate ions. When this solution dries up, the ions crystalize as CaSO4.2H2O, which is gypsum. Gypsum is soluble in water so when it is washed away, it leaves behind crumbling stone. On the other hand, when this gypsum accumulates, like it has in the case of the Taj Mahal, it attracts dust, carbon particles, dry-ash and other dark pollutants resulting in the blackening of the surface of the structure. As the result, over the years the gorgeous white monument has gradually yellowed as a result of this acid-base reaction.

Last weeks lecture on acids and bases was extremely fun and interesting! It was great to see how chemistry is so inherent in our daily lives, and how many common bases (substances that accept a proton) such as lime water and acids (substances that donate a proton) such as lemon juice or even our blood, are so readily available around us. An important acid base reaction that we did not discuss in class but is especially important for the environment is acid rain.

Acid rain occurs due to the burning of large amounts of coal. When coal is burned, the sulphur released reacts with the oxygen in the atmosphere to form sulphur dioxide, which reacts with more oxygen and water to form sulphuric acid. When it rains, the sulphuric acid mixed with rain, not only pollutes water ecosystems but also corrodes limestone. The reaction is as follows:

CaCO3 + H2SO4 –> H2CO3 + Ca++ + SO4- –

In the above reaction, limestone (CaCO3) is the base that accepts a proton from H2SO4 and is converted into carbonic acid (H2CO3).

Usually there isn’t enough sulphuric acid present in the rain to cause its pH to be below 6.5. However, at the peak of the acid rain problem in the 70s, the pH of the rain was as low as 5.5 which could seriously damage plants, and water ecosystems.

Although the problem of acid rain is much less of an issue now in the US and Canada due to the sanctions imposed by these governments which limited the burning of coal, some of the effects of acid rain are still being felt. In Canada for example, acid rain has resulted in a whole new species gaining prominence in its lakes. Due to acid rain, calcium was washed away from the soil and drainage areas which hurt the survival rates of a prominent species of plankton that required calcium to survive. A competing plankton, that has a jelly like surface, and requires little calcium, has now gained prominence and swimmers in Ontarios lakes now find themselves coated with this jelly-like substance after swimming in the lake.

Thus, it is important to realize that chemical changes to the environment (such as acid rain) have extremely long lasting impacts that persist even though the problem may be ‘solved’.

As we learned in class last week, hydrochloric acid (or stomach acid) is extremely acidic. It has a ph of between 3 and 1 making it almost as acidic as battery acid. If it were outside of our stomachs, it would be extremely dangerous to touch. So how does our stomach keep it from burning through and harming us?

Watch Stomach Acid Dissolve a Soda Tab in 12 Hours

The stomach is made of many layers including layers of muscle that help push food around while it is digesting. The innermost level however, the level that is in direct contact with the hydrochloric acid, is made up of specialized cells. There are parietal cells, g-cells, and epithelial cells. The parietal cells actually help produce the hydrochloric acid. Whenever you eat, more hydrochloric acid is created to help digest your food. The g-cells produce gastrin which helps the parietal cells create hydrochloric acid. The epithelial cells are the reason that your stomach acid is contained within your stomach. The epithelial cells produce a bicarbonate-rich solution that coats the inside of the stomach. Bicarbonate is a base and when it interacts with the acidic stomach acid, it neutralizes it. Water, the most neutral solution, is created in the process. Your body uses acids and bases to combat each other and keep you safe from yourself.

As we learned in class, pH follows a scale from 0 to 14 with 0-7 representing acidic solutions and above 7 representing basic solutions. Acids and bases can neutralize each other sort of like an average of two numbers. Though it is not as simple as taking an average of two pHs, it depends on quantities too, the core concept is that acids and bases can offset each other.

Stomach acid, HCl, usually has a pH between 1.5 and 3.5, which is quite acidic. I was interested in why when people feel stomach pains or indigestion, they take tums or pepto bismol. It is because they both contain baking soda, or NaHCO3 , which serves to offset the strong acid, neutralizing it somewhat and taking away the burning sensation. NaHCO3 if made into a solution in water has a pH between 9 and 11 so on the basic side of the spectrum. So when the HCl and the NaHCO3 come in contact with each other, the pH changes and becomes more neutral on the pH scale (closer to 7).

Our bodies do other acid base neutralization reactions. During digestion, food in the stomach is exposed to the strong HCl acid where it begins to break down. After, the basic environment of the small intestine releases and enzyme that works to neutralize the now acidic food so that it can continue being digested without the acid making us feel a burning sensation.