Lactose Intolerance

Lactose, also known as milk sugar, is the major carbohydrate found in milk. Its sweetness is 16% that of sucrose (table sugar). The lactose content of mother's milk obtained by nursing infants [7-8% (m/m)] is almost twice that in cow's milk [4-5% (m/m)]. Lactose supplies about 40% of the energy in human milk.

Many adults lack the enzyme lactase, necessary for the digestion of lactose; this causes lactose intolerance. When lactose molecules remain in the intestine undigestded, they attract water to themselves, causing fullness, discomport, cramping, nausea, and diarrhea. The level of lactase in humans varies with age. Most people have sufficient lactase during childhood years when milk is a needed calcium source. In adulthood, lactase levels decrease and lactose intolerance develops. This explains changes in milk-drinking habits of many adults. About one-third of Americans suffer from lactose intolerance.

The level of the enzyme lactase in humans varies widely among ethnic groups, indicating tht the trait is genetically determined (inherited). The occurence of lactose intolerance is lowest among Scandinavians and other nothern Europeans and highest among native Americans, Southeast Asians, Africans, and Greeks.

[Source: Chemical Principles by H. Stephen Stoker]

Hydrogen Sulfide

The hydrogen sulfide molecule is the sulfur analog of water, witha central sulful atom in place of the central oxygen atom.

Hydrogen sulfide is a gas at room temperature with an odor that resembles rotten eggs. Natural sources of it include bacterial decomposition of proteins and volcanic eruptions.

Nasal detection of hydrogen sulfide is possible at concentration as low as 0.02 part per million. Despite its easy detection, its presence can be dangerous because it exerts an anesthetic effects on nasal passages, causing the nose to rapidly lose its ability to detect its presence. Hydrogen sulfide is lethal at a concentration of 100 parts per million.

Decomposition of albumin, a sulfur-rich protein present in eggs, produces hydrogen sulfide. The pale green color often found at the interface of the yolk and white portion of a cooked egg is caused by the presence of hydrogen sulfide. Egg yolk is rich in iron-containing proteins, and H2S produced from albumin during cooking reacts with these proteins to form iron sulfide, the source of the green color.

[source: Chemical Principles by H. Stephen Stoker]

AirBag

An increasing number of automobiles are equipped with airbags that rapidly inflate on collision, before car occupants can be thrown forward after impact. The chemistry principle involved in the inflation process involves a controlled chemical explosion that produces a large volume of gas (which inflates the bag).

Nitrogen gas (N2) is the inflatant in most airbags. Airbags are activated when an impact causes a steel ball to compress a spring and electrically ignite a detonator cap, which in turn, causes sodium azide (NaN3) to decompose, forming nitrogen gas and metallic sodium. (100g of NaN3 produces 56L of Ns gas at 25 celsius.) The sodium metal produced, an undesirable decomposition product because of its reactivity, instantaneously reacts with iron(III) oxide, which is included in the reaction container, to produce sodium oxide (Na2O) and Iron (Fe).

[Source: H. Stephen Stoker, Chemical Principles]

Alkaloids

Caffeine, as well as nicotine, are examples of compounds that are called alkaloids. Alkaloids are physiologically active compounds produced by plants.

People in various parts of the world have known for centuries that physiological effects can be obtained by eating or chewing the leaves, roots, or bark of certain plants. Over 5000 different compounds that are physiologically active have been isolated from such plants.

Besides caffeine(coffee beans and tea leaves) and necotine(tobacco leaves), other alkaloids include cocaine (coca plant) atropine, and opium. The latter three alkaloids are currently used in medicine.

Quinine, which occurs in cinchoha bark, is used to treat malaria. Atropine, which is isolated from the bellodonna plant, is used to dilate the pupil of the eye in patients undergoing eye examination. Opium, the dried juice of the oriental poppy plant, has been used for centuries as a pain-killing drug. It contains numerous alkaloids, including morphine and codeine.

Ethylene

Ethylene, a colorless, flammable gas with a slightly sweet odor, is both a natural product and an important industrial chemical. Its molecular formula is C2H2.

Ethylene occurs naturally in small amounts in plants where it functions as a plant hormone. Many fruits and vegetables, especially citrus fruit and tomatoes, release ethylene as they ripen. The released ethylene triggers futher ripening.

The commercial fruit industry uses to advantage this ripening function for ethylene. Crops, such as bananas and tomatoes, are picked green to prevent spoiling and bruising during transportation to markets. At its destination, the fruit is exposed to ethylene gas, which stimulates the ripening process; 1kg of tomatoes can be ripened by exposure to 0.1 mg of ethylene.

Industrially, U.S. chemical manufacturers produce more ethylene each year than any other compound except sulfuric acid. The ethylene does not reach consumers directly; most of it goes into the production of plastics and synthetic fibers. Almost half of the ethylene produced is consumed in the production of the well-known plastic called polyethylene.

[source: Chemical Principles by H. Stephen Stoker]

Epinephrine

Adrenaline, also known as epinephrine, has the chemical formula C9H13O3N. It is a hormone released from the adrenal glands into the bloodstream, usually in response to pain, excitement, anger, or fear, that increases the level of glucose in the blood. The extra glucose, a key source of energy for body processes, in turn increases rate and force of heart contraction, muscular strength, and blood pressure. These changes cause the body to function at a "higher" level. For this reason, adrenaline is often called the "fight or flight" hormone.

Adrenaline-caused increase blood pressure results from increased heart action accompanied by constriction of peripheral blood vessels. Injectable local anesthetics usually contain adrenaline because it constricts blood vessels in the vicinity of the injection. This prevents the blood from rapidly distributing the anesthetic and prolongs the anesthetic effect in the target tissue. Andrenaline is also used to reduce hemorrahage.

[source: Chemical Principles by H. Stephen Stoker]

Acetaminophen

Acetaminophen has replaced aspirin as the most widely used of all nonprescription pain relievers. Its use now accounts for over half of the over-the-counter pain reliever market. It is marketed generally and under trade names such as Tylenol, Datril, Tempra, and Anacin-3. Acetaminophen's availability in a liquid form makes it an ideal medication for small children and other patients who have difficulty taking solid tablets.

Acetaminophen , often called the "Aspirin substitute," has no irritationg effect on intestinal tracts as does aspirin and yet has comparable pain-relieving effect and fever-reducing effects. However, it is not effective against inflammation as is aspirin and is thus of limited use for the aches and pains of arthritis. Also, acetaminophen does not have any blood thinning properties, as does aspirin, and therefore is not useful as an aid in reducing the risk of stroke and heart attack.

[source: Chemical Principles by H. Stephen Stoker]

Air Pollutant

Air pollutant are of two types: primary and secondary. Primary air pollutants are directly emitted into the atmosphere from natural and human-related sources. Secondary air pollutants are produced within the atmosphere from the interaction of primary polutants. Ozone is a secondary air pollutant. It is formed in a two-step process, within the atmosphere, from the interaction of NO2 (nitrogen dioxide, a primary pollutant), O2( normal atmospheric oxygen), and sunlight.

Atmosphere ozone levels are significantly influenced by meteorological conditions. Concentration levels are usually higher during the summer months, when there is more sunlight than during winter months. High ozone levels can, however, occur during winter months as a result of air stagnation (temperature inversion).

The secondary air pollutant ozone effects the eyes and the mucous membranes of the nose and throat. Its effects are more severe in individuals with chronic lung disease.

[source: Chemical Principles by H. Stephen Stoker]

Acid Rain

All rainfall, even that in the most pristine (unpolluted) areas, is acidic. This acidity results from the presence of carbon dioxide in the atmosphere, which reacts with water to produce carbonic acid. (The same reaction also occurs in a carbonated beverage.) Acid rain is rain with an acidity greater than that which normally occurs.

The cause of acid rain is sulfur oxide and nitrogen oxide air pollution. After being discharged into the atmosphere, these pollutants are chemically converted into sulfuric acid and nitric acid.

The most observable effect of acid rain is the slow, but definite, corrosion of carbonate-based building materials; this phenomenon is sometimes called "stone leprosy." Objects, including statues, made of limestone and marble, which are forms of calcium carbonate (CaCO3), are the most severly affected materials.

[source: Chemical Principles by H. Stephen Stoker]

Ozone Hole

Since the mid-1970s, scientists have observed a seasonal thinning (depletion) of ozone in the upper atmosphere (stratosphere) above Antartica. This phenomenon, which is commonly called the ozone hole, occurs in September and October of each year, the beginning of the Antarctic spring. Up to 70% of the ozone above Antarctica is lost during these two months.

Winter conditions in Antarctica include extreme cold (coldest location on Earth) and total darkness. When sunlight appears in the Spring, it triggers the chemical reactions that lead to ozone depletion. By the end of November, weather conditions are such that the ozone-depletion reactions stop. Then the ozone hole disappears as air from nonpolar areas flows into the polar region, replenishing the depleted ozone levels.

[source: Chemical Principles by H. Stephen Stoker]

Degree of Saturation of Fat

Medical research shows a correlation exists between dietary fat intake and heart and circulatory system problems. Additionally, some dietary fats have greater adverse effects on the human body than others. In general, the greater the degree of saturation of a fat, the greater its undesirable effects.

How do liquid-state dietary fats (plant oils) compare to solid-state dietary fats (animal fats) in terms of degree of saturation? Generally, plant oils are less saturated than animal fats, although coconut oil is an exception to the rule.

A measure of the degree of saturation of a fat (solid or liquid) is given by its iodine number, that is, by the number of grams of iodine that react with 100g of fat. The higher the iodine number, the lower the degree of saturation (a desirable situation in terms of diet).

Iodine numbers of selected solid and liquid fats are as follows:

coconut oil 8-10
butter 25-40
beef tallow 30-45
lard 45-70
olive oil 75-95
peanut oil 85-100
cottonseed oil 100-117
corn oil 115-130
canola oil 125-135
soybean oil 125-140
safflower oil 130-140
sunflower oil 130-145

[source: Chemical Principles by H. Stephen Stoker]

Water

On average, per day, approximately 2400mL of water enters and leaves the body. [* (2400mL)(1fl oz/29.57mL)(1qt/32fl oz)(1gal/4qt)=.634 gallon, approximately 1/2 gal]

Water enters the body in three different ways: (1) the liquids we drink (1500mL) [*(1500mL)(.001L/1mL)(1pt/.4732L=3.17pt], (2) water in foods (700mL=1.479pt), and (3) water produced in cells as a by-produce of the reactions by which food is broken down (200mL=.423pt).

Water normally leaves the body by four mechanisms: (1) urine produced in the kidneys (1400mL=.370gal which is approximately 1/4 gal), (2) water in expired air from the lungs (350mL=.740pt), (3) persperation from the skin (450mL=.950pt), and (4) feces formed in the intestines (200mL=.423pt gal).

For a body to function normally, the total volume of water intering the body must equal the total volume of water leaving the body. Serious dehydration can occur in an adult if there is a 10% net loss in total body fluid, and a 20% loss of fluid can be fatal. An infant suffers dehydration with a 5-10% loss in body fluid.

[source: Chemical Principles by H. Stephen Stoker]

Carbon Dioxide

There are three main sources of carbon dioxide discharged into the atmosphere: respiratory of plants and animals (93%), forest fires and other burning of plant materials (2%), and the burning of fossil fuels such as oil, coal, and natural gas(5%). Most (95%) of this released carbon dioxide is removed by the natural processes of photosynthesis and uptake of carbon dioxide by the oceans. There is, however, a net gain in atmospheric carbon dioxide each year.

The environmental impact of increased carbon dioxide levels is often call the greenhouse effect, an effect that could produce global warming (an increase in average air temperature). Carbon dioxide traps some of the energy radiated by the earth as it cools at night, thus preventing the radiation from escaping to outer space. The trapped energy causes an increased warming of the atmosphere.

[source: Chemical Principles by H. Stephen Stoker]

Hydrochloric Acid

Secreted by the gastric glands of the stomach, gatric juice is a mixture of water, enzymes, and hydrocloric acid. The presence of hydrochloric acid in gastric juice causes the sensation of heartburn if it is refluxed into the esophagus.

The acidity of gatric juice (hydrochloric acid) prevents bacterial growth in the stomach, kills most bacteria that enter the body with food, and effects the partial breakdown of protein by activation protein-digesting enzymes. (Digestion of carbohydrates and fats occur primarily in the small intestine rather than in the stomach.)

The concentration of hydrochloric acid in gastric juice is approximately 5% by mass, creating an acidity effect about the same as that of lemon juice. Hydrochloric acid is known commercially as muriatic acid and can be purchased under this name in hardware stores.

[source: Chemical Principles by H. Stephen stoker]

Oxygen

The substance oxygen exists in two gaseous forms: (1) dioxygen, which is the oxygen we breathe, and (2) trioxygen, which is also known as ozone. In contrast to the colorless and odorless dioxygen we breathe, ozone has a light-blue color and its pungent odor is that associated with thunderstorms; lightning discharges produce ozone.

Naturally occuring ozone present in the upper atmosphere (the "ozone layer") screens out 95-98% of the ultraviolet light that comes from the sun. Excessive exposure to ultraviolet light causes sunburn and can contribute to the development of certain types of skin cancer. The presence of ozone in the upper atmosphere is a very desirable situation.

Ozone, under certain conditions, can also be found in the lower atmosphere. Here, its presence is considered undesirable. In the lower atmosphere, ozone is produced during photochemical smog formation. As the "active ingredient" in such smog, it is damaging to plants and to the human lungs.

[source: Chemical Principles by H. Stephen Stoker]

Methane Gas

Back to basic

Methane CH4 -> 1 Carbon & 4 Hydrogen

The small amount of methane present in Earth's atmosphere comes from terrestial sources. The decomposition of animal and plant matter in an oxygen-defecient environment-swamps, marshes, bogs-produces methane. A common name of methane, mash gas, refers to the production of methane in this matter.

Bacteria that live in termines and in the digestive tracts of plant-eating amimals have the ability to produce methane from plant materials. The methane output of a large cow (belching and flatulence) can reach 20 liters per day.

*20 liter (1.06qt/1 liter)(1gal/4qt)=5.3 gal, so approximately 5 gallons if my calculations were right...

Methane gas is also found associated with coal and petroleum deposits. That associated with petroleum is most often recovered, processed, and marketed as natural gas. The processed natural gas is 85-95% methane by volume. Because methane is odorless, an odorant (smelly substance) must be added to the processed natural gas used in home heating. Otherwise, natural gas leaks could not be detected.

[Source: Chemical Principles by H. Stephen Stoker]