Carbon Chemistry

The Big Picture

Carbon Compounds Before 1828: Chemists believed compounds could only be divided two ways, into compounds they produced and compounds that organisms produced. In 1828: Fredrick Wohler produced urea. Urea was the product of him synthesizing an organic compound (urea is a product of reactions in the livers of many organisms). There are millions of organic compounds and they contain carbon and hydrogen. They are often combined with other elements.

Forms of Carbon Diamond – drills & saws Graphite – pencil lead Fullerenes – help medicine get inside of cells Bonus: Nanotubes – help wires conduct electricity The Chemistry of Carbon - Learn 360 (12 min) Carbon Chemistry - Learn 360 (43 min)

Hydrocarbons The simplest organic compounds Contains the elements hydrogen and carbon only Methane gas, Propane gas, Butane gas Gasoline is a mixture of several hydrocarbons Properties Like most organic compounds, they do not mix well with water Flammable

Saturated versus Unsaturated Hydrocarbons Saturated Hydrocarbons contain only single bonds, so they have the maximum amount of hydrogen atoms on their carbon chains Unsaturated Hydrocarbons contain double or triple bonds, so they have fewer hydrogen atoms on their carbon chains Look:

Saturated Hydrocarbons and their Structural Formulas A structural formula shows the kind, number, and arrangement of atoms in a molecule. Straights Chains Branched Chains Rings

Unsaturated Hydrocarbons Alkenes: fruit bearing plants produce ethene which controls the rate at which fruits ripen; double bond between two carbon atoms; end in –ene Alkynes: straight or branched chain hydrocarbons that have one or more triple bonds; end in –yne; example=welders use ethyne used in torch to cut metal Aromatic Hydrocarbons: ring structure; six bonds in the ring are identical; strong aroma; example=benzene in gasoline

Fossil Fuels Hydrocarbons formed from plants and animals that lived in Earth’s oceans and swamps millions of years ago are fossil fuels. Type of fossil fuel produces depends on the origin of the organic material and the conditions under which it decays. Coal: most hydrocarbons in coal are aromatic hydrocarbons with high molar masses; high ration of carbon to hydrogen so burning it produces more soot than burning other fossil fuel Natural Gas: formed from the remains of marine organisms; main component is methane but also contains ethane, propane and isomers of butane Petroleum: formed from the remains of marine organisms; called crude oil; found deep beneath Earth’s surface; mainly long-branched alkanes and alkenes; to be useful, it must be separated into simpler mixtures through distillation

Combustion of Fossil Fuels Acid Rain Combustion produces acid rain (instead of rain with pH of 5.6, can be as low as 2.7) Damages stone structures, metal and concrete Sulfur dioxide and nitrogen oxides dissolve in water droplets forming sulfuric and nitric acids Complete Combustion The primary products of the complete combustion of fossil fuel are carbon dioxide and water. Incomplete Combustion Stoves, furnaces Insufficient oxygen= Produces carbon monoxide (colorless, odorless poisonous gas)

Boiling Points of Hydrocarbons Calculating: What is the temperature difference between the boiling points of C3H8 and C5H12? About 78ºC

Substituted Hydrocarbons Like a drill with different attachments, a carbon atom in an organic compound can have four attachments. The attachments can all be different but sometimes they are identical.

Substituted Hydrocarbons Carbon can form stable bonds with several other elements including oxygen, nitrogen, sulfur and several halogens. If ONE atom of another element is substituted for a hydrogen atom in a hydrocarbon, the hydrocarbon is called a substituted hydrocarbon. Examples: Compounds containing halogens (period 17), Freon: once used as a cooling agent in refrigerators and car air conditioners Compounds containing alcohols, Methanol: used in solutions for de-icing airplanes Compounds containing organic acids, Formic acid: in stinging nettle and produced by ants

Focusing on Alcohols The functional group in an alcohol is a hydroxyl group, -OH. The name of an alcohol ends in –ol. Examples: Methanol = fuel for motorcycles (and deicing planes as previously discussed) Ethanol = mixes with gasoline to help gas burn more completely An alcohol can be made by reacting an alkene with water.

Organic Acids and Bases The sharp, sour taste of a lemon comes from citric acid, an organic acid. The functional group in organic acids is a carboxyl group, -COOH. Names of organic acids, end in –oic. They tend to have sharp tastes and strong odors. Example: Methanoic acid, aka formic acid (remember ants and stinging nettle?) Ethanoic acid and water is vinegar and is also known as acetic acid. The functional group in bases, or amines, is an amino group, -NH2. Amines are found in paints, dyes and disinfectants.

Esters When organic acids react with alcohols they form esters. Uses: A second product of the reaction is water. The reaction is reversible. Ethanoic acid can react with methanol to produce methyl ethanoate. Uses: Esters are used in processed foods for flavoring. Flowers produce esters with distinctive odors. Flavoring: strawberry, banana and grape

Polymers Consider freight trains… Different types of cargo are transported in different types of cars Like freight trains, some molecules are built up from smaller units linked together. A polymer is a large molecule that forms when many smaller molecules are linked together by covalent bonds. The smaller molecules that join together to form a polymer are monomers. Polymers can be classified as natural polymers or synthetic polymers.

Reviewing How Polymers are Formed Recall Carbon’s Chains and Rings Carbon atoms can form four covalent bonds Carbon atoms can bond to each other in straight and branched chains and ring-shaped groups Carbons Compounds and Polymers Polymers form when chemical bonds link large numbers of monomers in a repeating pattern. Monomers are the building blocks of polymers. Mono = One Poly = Many

Natural Polymers Four types of polymers produced in plant and animal cells are starches, cellulose, nucleic aids and proteins. Carbohydrates: 1. Starches: simple sugars, straight chains or rings Slightly more complex sugars such as sucrose and polymers (built from sugar monomers) are also classified as carbohydrates Pasta, bread. some vegetables (potatoes) 2. Cellulose: Another type of carbohydrate Main component of cotton and wood (provides them with strength) Most abundant of all organic compounds In fruits and vegetables 3000 or more glucose monomers Non-digestible by humans

Natural Polymers Continued 3. Nucleic Acids: Large nitrogen-containing polymers found mainly in the nuclei of cells Two types: DNA an RNA Monomers are nucleotides 4. Proteins: A polymer in which at least 100 amino acid monomers are linked through bonds between an amino group and a carboxyl group. An amino acid is a compound that contains both carboxyl and amino functional groups in the same molecule (your body needs about 20 to function) Your body can’t produce glycine so you must get it from food Instructions for making proteins are stored in DNA Proteins make up your hair, fingernails, muscles and hemoglobin in your blood Protein polymers form in very long strands

Synthetic Polymers Man-made Plastics Many types of clothing (like polyester and rayon) Carpet Gum Toothpaste Styrofoam Rubber – sap vs resisting wear and being less likely to leak Nylon – strong, durable and shiny Polyethylene – plastic wrap, milk bottles

Polymers video clip http://youtu.be/8YUiRKWPKl8

Reactions in Cells Historical connection: Consider whale oil (and other animal fats) being used as lamp oil As fats burn, they release energy in the form of heat and light and combine oxygen and produce carbon dioxide and water. In lamps, combustion happened quickly but not in animal cells. Some reactions in cells go to completion and some reach equilibrium point. Sometimes a catalyst is needed. Photosynthesis and cellular respiration are two processes that allow organisms to meet their energy needs.

Photosynthesis The sun is the primary source of energy for most plants and animals. During photosynthesis, plants chemically combine carbon dioxide and water into carbohydrates. The process requires light and chlorophyll, a green pigment in plants. During photosynthesis, energy from sunlight is converted into chemical energy. Photosynthesis involves a complex series of chemical reactions. When all the reactions are complete, the energy form sunlight has been stored in the covalent bonds of molecules.

Cellular Respiration Your body needs energy for EVERYTHING!!! To cry, laugh, heal a cut, climb a tree, and even to sleep! During cellular respiration, the energy stored in the products of photosynthesis is released. CO2 and H2O are reactants in photosynthesis and products of cellular respiration Carbohydrates and oxygen are reactants in cellular respiration and products of photosynthesis Glucose(comes from simple sugar or starches)) reacting with oxygen Fats are also a good source of energy

Enzymes and Vitamins Enzymes and vitamins are compounds that help cells functions efficiently at normal body temperature. Without them, reactions that take place in cells would not happen fast enough to keep your cells alive. Enzymes: Needed by cells to digest food a(extracting energy from it) Proteins that act as catalysts for reactions in cells Speed up reactions without raising temperature Thousands in your body Vitamins Organic compounds that organisms need in small amounts but can’t produce themselves Vitamins that dissolve in water get eliminated daily and need to be replaced (Ex. Vitamin C) Vitamins that dissolve in fat build up over time in the body (Vitamin A)