Aluminum. Alkaline Batteries

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1 Aluminum Aluminum, the third most abundant element in the Earth's crust, is very reactive. Aluminum is commonly extracted from bauxite or aluminum oxide (Al 2 O 3 ) to make products like cans and foil. Pure aluminum is a soft, silvery white metal that is very malleable. Malleable means that aluminum can be pounded or rolled into thin foil sheets about 0.02 mm thick. Gold is even more malleable and be made into sheets a few atoms thick! Alkaline Batteries Whether AAA, AA, C, or D, all alkaline batteries use a few basic components to produce an electric current: two electrodes and an electrolyte. Chemical energy is changed to electrical energy as electrons (fast moving negative particles inside atoms) move from one electrode to the other through a chemical solution. One of the electrodes is zinc. The other electrode is made of manganese dioxide (manganese and oxygen) and graphite (another name for carbon). Electrons flow from the zinc electrode to the manganese dioxide-graphite electrode through a solution called an electrolyte. Potassium hydroxide (potassium, hydrogen, and oxygen) makes up the solution. Other battery components include a nickel-plated steel (nickel, iron, carbon) covering and tin-plated brass (tin, copper, zinc) conductor. Recycling batteries is good for the environment. Table Salt Table salt is composed of the elements sodium and chlorine. Salt is essential for our survival. It regulates our body's fluid balance. But, too much salt can lead to high blood pressure. This crystalline solid can be white, gray, pink, or even yellow depending on where it was formed. Salt forms as a mineral deposit when seawater evaporates. Deposits can both be found on top and under the ground. Most people don't know that a large salt mine exists under Detroit, Michigan! We commonly use refined salt or salt that has the impurities removed. Sometimes iodine is added to table salt during refining to prevent a condition called a goiter. A goiter is an enlargement of the thyroid gland in the neck in response to the lack of iodine in the diet. Air Air is a mixture of gases. Air is mostly nitrogen (78.5%) and oxygen (21%) mixed with small amounts of inert gases: helium, neon, argon, krypton, and xenon. Inert gases are chemically inactive because they rarely react with other elements. Also found in the air are small amounts of pure hydrogen and greenhouse gases: water vapor (H 2O), carbon dioxide (CO 2), and methane (CH 4). Greenhouse gases absorb heat radiated from the Earth's surface trapping heat in the atmosphere. Without these gases in the air, the Earth's surface would be about 38 C cooler. Air pollutants from the burning of fossil fuels create problems related to health and can lead to breathing difficulties. Chemical pollutants, like those from aerosols, deplete the ozone (O 3) layer. The ozone layer protects us from skin cancers caused by increased exposure to UV radiation.

2 Steel Iron, the main element in steel, is a heavy, hard, and ductile metal. It is inexpensive, abundant, and has many uses. Iron has been known since prehistoric times. It was called ferrum, its Latin name, before it was known as iron. Since iron readily combines with oxygen, it is naturally found in hematite or magnetite, both oxides of iron. After retrieval from a mine, hematite is broken down into iron and oxygen by heating. Steel is an iron-carbon alloy. An alloy forms when two or more metals are melted together. When an alloy solidifies, it is considered a solid solution. Steel is mostly iron with varying amounts of dissolved carbon. Alloys have physical properties different from their individual elements. By adding carbon to iron, chemists can make a metal that is stronger than iron by itself. Earth The planet Earth is made up of many different elements and compounds. Although more than 4000 minerals (the building blocks of rocks) are known, most are made of different combinations of a few elements. The three most common elements found in minerals are oxygen (78%), silicon (~21%), and aluminum (~7%). Five other common elements found in minerals are iron, sodium, calcium, magnesium, and potassium. Trace amounts of many other elements are also present. If you could cut the Earth in half, it would look a little like a peach! Earth's outside layer is a thin, solid crust forming the surface. Earth's crust is mostly silicates (silicon and oxygen compounds). Underneath the crust is viscous mantle made of silicates and magnesium oxides. The Earth's center is a solid core made mostly of iron and other dense metals. Table Sugar (Sucrose) Table sugar is a sweet tasting carbohydrate. Carbohydrates are compounds consisting of carbon, hydrogen, and oxygen. Table sugar is the common name for the sugar that chemists call sucrose. Sugarcane and sugar beets are rich in sucrose and used to produce table sugar. Sucrose is easily digested or broken down into the smaller sugar molecules of glucose and fructose. These smaller sugar molecules easily enter the blood stream and the body's cells to provide quick energy. Insulin, produced by the pancreas, helps glucose enter cells. Unfortunately, millions of Americans suffer from diabetes, a condition caused by the inability to produce enough insulin to fuel their cells. Once diagnosed, diabetics must learn how to monitor their sugar intake and make lifestyle changes as needed.

3 Earth's Sun Although no one has ever visited the Sun, scientists know that the Sun's photosphere (300 mile deep outer gas surface) is made of hydrogen (90%) and helium (10%). But, if we haven't been to the Sun, how do we know what it is made of? The answer is: spectroscopy. When viewed through a spectroscope, the gas phase of each element emits a unique spectrum or band of colors. When scientists look at the Sun's spectrum, they can identify the elements present just as a fingerprint patter can identify a person. The Sun has a constantly changing, active surface marked with sunspots (dark blemishes), prominences (cloudlike gas motion), and explosive events like solar flares. Flare activity can disrupt satellite communication and is carefully monitored from the Earth. Human Body The human body is mostly composed of hydrogen (~65%), oxygen (~26%), and carbon (~8%). Smaller amounts (~1.25% to 0.06%) of nitrogen, phosphorus, and sulfur are also present. The trace elements (~0.001%) of sodium, magnesium, chlorine, potassium, calcium, manganese, iron, copper, iodine, cobalt, zinc, selenium, and fluorine are also needed for growth and development. Water (H 2O) is the most abundant molecule in the human body. Next are the organic molecules: proteins (e.g. muscle), fats (e.g. cholesterol), carbohydrates (e.g. sugars & starches), and nucleic acids (e.g. DNA). These organic molecules are made of carbon atoms combined with hydrogen, oxygen, and other elements. Because there are so many different arrangements of carbon atoms with other atoms, a special field of chemistry called biochemistry focuses on the chemistry of living things. Compact Fluorescent Light Bulbs Americans are switching! Compact fluorescent light bulbs are CFL's cost a bit more than incandescent bulbs, but CFL's use less electricity and last longer. Incandescent bulbs use electricity to heat a tungsten wire to give off light (and heat). CFL's are filled with argon gas and a tiny amount of mercury gas. When an electron stream moves through the gases, the electrons give off energy. The energy is absorbed by the CFL's interior phosphor coating. The coating fluoresces are gives off light as long as there is electrical current. Phosphors differ in compact fluorescent bulbs. Phosphors are made from many different elements like: yttrium, europium, gadolinium, zinc, magnesium, boron, cerium, manganese, lanthanum, phosphorus, terbium, aluminum, barium, and strontium. Because CFL's contain small amounts of poisonous mercury, they should be recycled unbroken.

4 Microchip Microchips are the teeny, tiny "brains" of your computer, cell phone, calculator, and all other smart devices. They are made primarily from silicon, a semiconductor that allows the flow of electrons to conduct electricity. To make a chip, silicon crystal cylinders are grown from molten silicon. The cylinders are then sliced into wafers to form the chips. Each chip can contain thousands of electrical pathways turned on and off by miniscule transistors. Today, thousands of transistors are part of the microchip's integrated circuit that can process 10 billion bits of information each second. Glass Glassmaking is a complex chemical process. The glassmaker must know exactly how to mix the right amount and combination of chemicals. First, silicon dioxide (SiO 2) is melted with sodium carbonate (Na 2CO 3). Next, other compounds are added. For example, lead may be added to increase the shine and appearance of glass. Sodium sulfate (Na 2SO 4) may be added to reduce bubble formation upon cooling. Limestone or calcium oxide (CaO) may be added to reduce breakage. If color is needed, more substances are added. For example, adding cobalt give glass a deep blue color. It is important to recycle glass because less energy is used to make recycled glass products and less carbon dioxide is released into the atmosphere. Hamburger and Fries Instead of saying, "I'll have a burger and fries," try asking for some carbon, oxygen, hydrogen, sodium, and chloride atoms next time you order fast food! Since burgers are made of proteins and fats, they are mostly carbon, hydrogen, and oxygen atoms. The carbohydrate bun also contains carbon, hydrogen, and oxygen atoms. Lettuce, pickles, and tomatoes are also carbohydrates. And, the fries are potatoes (more carbs) fried in oil (fat). The sodium and chlorine atoms found in salt add extra flavor. Deciding the size of the burger to order depends on your individualdaily nutritional requirements. The difference between a regular size burger and a large burger (no cheese) can be the difference between 22% and 43% of your daily sodium requirement or 13% compared to 43% of your daily fat needs! and that doesn't include the fries.

5 Penny The elements in pennies have changed over time. The first pennies were made out of pure copper metal. Later small amounts of the metals tin and zinc were added to the copper to make a bronze alloy. A mixture of metals is called an alloy. In the mid-1800's, the penny was made of copper and nickel, but in less than ten years, it was changed back to copper, tin, and zinc. In the early 1960's the tin was taken out of the penny making it 95% copper and 5% zinc. In the 1980's the composition changed drastically. Today's pennies are copper-plated zinc or about 97.5% and 2.5% copper. Coin collectors are always on the lookout for a special penny made during World War II. In 1943, pennies were made out of zinc-coated steel (iron and carbon) to conserve copper for military needs. However, a few rare 1943 copper pennies were made. They could be worth a mint! Green Plants Green plants are able to produce their own food by photosynthesis. During photosynthesis, plants convert light energy from the sun into chemical energy. Using chlorophyll and light energy, plants take the carbon dioxide (CO 2) from the air and react it with water (H 2O) to make glucose (C 6H 12O 6), an energy rich carbohydrate. During photosynthesis, plants release oxygen into the air. Plants also "breathe" or undergo respiration. This process is the reverse of photosynthesis. Sugars are combined with oxygen to produce energy for the plant with CO 2 and H 2O released into the atmosphere. Plants, like humans, contain proteins, fats, and carbohydrates. Thus, they contain large amounts of the elements hydrogen, oxygen, and carbon. Also present are varying amounts of nitrogen, calcium, potassium, magnesium, sulfur, and aluminum. Seawater Seawater is H 2O with dissolved substances like oxygen (O 2), carbon dioxide (CO 2), and sea salts: chlorine, sodium, sulfur, magnesium, calcium, potassium, bromine, boron, strontium, and fluorine. The sea salts are responsible for the water's salinity. Salinity changes due to the environmental conditions. For example, the salinity of an ocean is lower in cold water than in the warmer water at the equator. In warm and dry regions with little rainfall, water evaporates quickly. Thus, warm seas (Caribbean Sea) have a higher salinity than cooler seas (Arctic Ocean). Fresh water is scarce all over the world. In the U. S., the coastal town of Santa Barbara, California, had desalination plants to remove salt from seawater and help solve its fresh water shortages. Unfortunately, the desalination of water is very costly and new methods are being researched.