Organic Chemistry Past Paper PDF

Science (Tuesday) ORGANIC CHEMISTRY Carbon highly unique element neutral, no overall charge tetravalent - 4 valence electrons can easily form covalent bonds with other atoms...

Science (Tuesday) ORGANIC CHEMISTRY Carbon highly unique element neutral, no overall charge tetravalent - 4 valence electrons can easily form covalent bonds with other atoms exhibits carbon catenation - when carbon bonds with another carbon atom to become stable compounds containing carbon: organic compounds results in a wide range of organic molecules Hydrocarbons hydrogen and carbon 1. Alkanes 2n+2 single bonds between C atoms used as fuels and solvents Ex: Nonane STRUCTURAL FORM CONDENSED FORM SKELETAL FORM Science (Tuesday) 1  2. Cycloalkanes 2n single bonds between C atoms form a closed ring structure used as fuels, solvents, lubricants, and anesthetics Ex: Cyclohexane (C6H12) STRUCTURAL FORM CONDENSED FORM SKELETAL FORM 3. Alkenes 2n at least 1 double bond between two C atm used as raw materials for plastics and polymers Ex: Propene STRUCTURAL FORM CONDENSED FORM Science (Tuesday) 2  SKELETAL FORM 4. Alkynes 2n-2 at least 1 triple bond between C atoms used to manufacture other organic molecules Ex: Pentyne (C5H8) STRUCTURAL FORM CONDENSED FORM SKELETAL FORM FUNCTIONAL GROUPS at least one H atom may be replaced by either - another atom of a different element Science (Tuesday) 3  - a group of atoms Functional group: a combination of atoms with a unique set of chemical properties Resulting Compound = hydrocarbon derivative gives the identity of the organic compound 1. Alcohols R — O — H characterized by the hydroxyl group (-OH) very common in nature used as fuel, solvent, or antimicrobial agent an organic compound becomes alcohol when a hydroxyl group (-OH) is introduced or attached to its carbon chain or ring 2. Ethers R — O — R’ characterized by the oxygen atom bonded between two R groups used as solvents for fats, oils, waxes, perfumes, and anesthetics 3. Aldehydes characterized by the carbonyl group (C=O) and at least one H atom attached to it uses: solvents, raw materials or polymer, preservation specimens Examples: - Formaldehyde the liquid people use to preserve specimens - Cinnamaldehyde Science (Tuesday) 4  a naturally occurring flavonoid that gives the spice cinnamon its flavor and odor 4. Ketones characterized by the carbonyl group attached to two alkyl groups uses: solvents for plastics and synthetic fabrics, found in pain thinners, and nail polish removers Example: Acetone nail polish remover 5. Carboxylic Acids characterized by the carboxyl group (-COOH) uses: polymers, soaps, cosmetics, food, pharmaceutical products Examples: - Acetic Acid give vinegar its characteristic odor - Lactic Acid a chemical your body produces when your cells break down carbohydrates for energy Science (Tuesday) 5  also basically spoiled milk 6. Esters characterized by the -COOR functional group pleasant odors/flavors used in artificial flavoring gives the fruit its scent and flavor Examples: - Methyl butyrate flavorings, extracts, and perfumery, and as a solvent - Ethyl Butyrate flavorings, extracts, and perfumery, and as a solvent also basically spoiled milk 7. Amines characterized by the -NH2 functional group Science (Tuesday) 6  alkyl derivatives of ammonia distinct foul odor Examples: Putrescine and cadaverine - they cause the smell of dead animals THE MOLE CONCEPT The Mole amount of substance that contains as many particles as atoms in 12g of C-12 particles are counted in moles Wilhelm Ostwald Avogadro’s Number named after Amadeo Avogadro 1 mole = 6.02 x 10^23 particles of any substance 1 mole Au = 6.02 x 10^23 particles Au 1 mole CO2 = 6.02 x 10^23 particles CO2 1 mole NaCl = 6.02 x 10^23 NaCl formula units Molar Mass mass of one mole of a substance unit: grams per mole (g/mol) MM = atomic mass mass of one Fe atom = 55.85 amu mass of one mole of Fe = 55.85 grams molar mass of Fe = 55.85 g/mol 1 mol of Fe = = 6.02 x 10^23 NaCl formula units REMEMBER MM = molecular mass of a covalent compound MM = formula mass of an ionic compound Molecules & formula units are made of atoms Science (Tuesday) 7  Molecular mass and formula units = sum of atomic masses of the atoms in the compound Find the Molar Mass of H2O Atomic Mass of H = Atomic Mass of O = MM = (1.008 amu H x 2 atoms) + 16 amu MM = 18.02 amu = 18.02 g/mol The Mole Concept used to determine different quantities of substances Interconversion of quantities: Number of moles (mol) Mass (grams) Number of particles dimensional analysis used to cancel out given units desired units remain Molar Brick Road LOOKING FOR MOLES: divide LOOKING FOR THE MASS: multiply Science (Tuesday) 8