Chemistry 6-13 PDF

# Nonmetals and Their Molecular Compounds Structure and Properties - 2 or more nonmetals - binary covalent compounds - sharing electrons between atoms - molecular formulas ## IUPAC - International Union of Pure and Applied Chemistry - Electronegativity ## Rules 1. Different Groups: Closer to th...

# Nonmetals and Their Molecular Compounds Structure and Properties - 2 or more nonmetals - binary covalent compounds - sharing electrons between atoms - molecular formulas ## IUPAC - International Union of Pure and Applied Chemistry - Electronegativity ## Rules 1. Different Groups: Closer to the Left side - First 2. Same Group: Lower - First 3. Groups 13-15 are written first before Hydrogen 4. Hydrogen - first - groups 16-17 # Polar Covalent Bonds - atoms - different electronegativities - share electrons # Nonpolar Covalent Bonds - electrons are shared equally between atoms ## Electronegativity - measure of how strongly atoms attract bonding electrons to themselves # Steps in Drawing Lewis Dot Structure in Covalent Compound 1. Total Valence Electrons 2. Determine the central atom and arrange the atoms to show specific bonds (least electronegativity – central atom) 3. place a bonding pair of electrons between each pair of adjacent atoms to give a single bond # Single Bonds - 2 atoms - 1 pair # Multiple Bonds - 2 or 3 electron pairs - shared between two atoms # Steps for Polyatomic Ions (add or subtract the indicated charge) 1. Valence Electrons 2. Central Atom 3. Bonding Pair of Electrons 4. Distribute remaining electrons 5. bracket # Resonance Structure - set of 2 or more lewis structures - delocalized electrons that cannot be expressed by a single lewis formula # Expanded Octet # The Geometry of Simple Compounds ## Simple Compounds - pure substances made up of two or more elements that are held together by chemical bonds ## Molecular geometry - may be described according to the bond angles between two adjacent bonds # VSEPR Theory -Valence Shell Electron Pair Repulsion Theory is a model used to predict and describe the 3-D molecular geometry based on the number of valence shell electron bond pairs among the atoms in a molecule or ion ## Linear - central atom is bonded to 2 other atoms at a bond angle of 180 degrees ## Trigonal Planar - 1 atom in the center and 3 atoms at the corners of an equilateral triangle, known as peripheral atoms, all in the same plane - ligands - ideal trigonal planar species – identical - 120 degrees ## Angular - non-linear - bond angles less than 180 degrees - bent or v-shaped ## Tetrahedral - central atom - surrounded by 4 other atoms - 109.5 ## Trigonal Bipyramidal - central atom - surrounded by 5 other atoms ## Octahedral - 6 atoms - symmetrically arranged around a central atom # Determine the Polarity of Simple Molecules ## Molecule - group of two or more atoms held together by chemical bonds ## Polarity - how evenly electrons are shared between atoms in a molecule ## 2 factors ### Polarity of Bonds - distribution of electric charge across a chemical bond between two atoms ### Geometrical Shape of the Molecule - three-dimensional shape in space, which is determined by the central atom, surrounding atoms, and electron pairs ## factors ### Electronegativity Difference - different electronegativities - share electrons unevenly (polar bonds) - larger difference - more polar bonds ### Molecular Geometry -symmetrical - non-polar molecules # Covalent Compound - formed by - covalent bonds - atoms - share 1 or more pairs of valence electrons # Ionic Compound - (at least) 1 metal 1 nonmetal - ionic bonding # Bond Polarity - relative tendency of an atom to attract electrons to itself when chemically combined with another atom - higher - electronegativity - attract | DIFFERENCE IN ELECTRONEGATIVITY | TYPE OF COMPOUND (BOND POLARITY)| |---|--- | Greater than or equal to 1.7| IONIC| | 0.5 - 1.6 | POLAR| | Less than 0.5 | COVALENT NON-POLAR| # Molecular Polarity - both bond polarity & molecular shape - overall molecular polarity # Functional Groups - specific groups of atoms within a molecule that are responsible for its characteristic chemical reactions and properties - building blocks of organic chemistry # Organic Compounds - any compounds whose molecules contain carbon and hydrogen (hydrocarbons) or a compound that is the derivative of it # Hydrocarbons - carbon and hydrogen - Alkane, Alkene, Alkyne, Aromatic # Hydrocarbon Derivatives - from hydrocarbons - at least 1 of the hydrogen atoms in a hydrocarbon derivative is substituted with a different atom # Naming Hydrocarbons | ROOT WORD (# of carbons) | SUFFIX| |---|---| | ane | | ene | | yne | # Aromatic - sigma bonds and delocalized pi electrons between carbon atoms in a ring # Hydrocarbon Derivatives ## Halides - Haloalkanes - 1 or more hydrogen atoms are replaced by halogen atoms like fluorine, chlorine, bromine and iodine - Cholorform (CHC13) ## Alcohols - contain a hydroxyl group (-OH) attached to a carbon atom in place of a hydrogen atom - -OH group - makes alcohols polar and able to form hydrogen bonds - Ethanol (C2H5OH) ## Ethers - oxygen atom linking 2 hydrocarbon groups - R-O-R' - ethers less reactive than alcohols and useful as solvents - Diethyl ether (C2H5-OC2H5) # No. Carbon Atoms Prefix for Main Chain | Number of Carbon Atoms | Prefix | |---|---| |1 | meth-| |2 | eth-| |3 | prop-| |4 | but-| |5 | pent-| |6 | hex-| |7 | hept-| |8 | oct-| |9 | non-| |10 | dec-| # Aldehydes and Ketones - contain a carbonyl group (C=O) - Aldehydes - end of the carbon chain (R-CHO) - reactive & fragrant - Formaldehyde (CH2O) - Ketones - between 2 carbon atoms (R-CO-R') - less reactive - Acetone (CH3COCH3) # Carboxylic Acids - have a carboxylic group (-COOH) - carbonyl group attached to a hydroxyl group - acidic, able to donate hydrogen ions in a solution - Acetic Acid (CH3COOH) # Esters - derived from carboxylic acids but the hydrogen in the -COOH group is replaced by an aalkyl group (R-COOR) - pleasant, fruity smells and are used in flavorings and fragrances - Ethyl acetate (CH3COOCHO2CH3) # Amines - 1 or more nitrogen atoms with hydrogen or hydrocarbon groups attached (like -NH2, -NHR, or -NR2) - basic (alkaline) and often smell fishy - Methylamine (CH3Nh2) # Amides - related to carboxylic acids - the -OH of the -COOH s replaced by amine (-NH2) - proteins more stable than ester - Acetamide (Ch3CONH2) # Nitriles - cyano group (C=N), where carbon is triple-bonded to nitrogen - plastics and pharmaceuticals - Acetonitrile (Ch3CN) # Structural Isomerism ## Structure - spatial arrangement of atoms in a molecule - condensed, skeletal, lewis, structural ## Isomerism - the existence of molecules that have the same numbers of the same kinds of atoms but differ in chemical and physical properties - isomers |Isomerism|Isomerism| |---|---| |Structural isomerism|Stereoisomerism| |positional|Conformational| |chain|Configurational| |functional group|Optical| |Geometric| ## Structural Isomerism - same molecular formula - different connections of atoms ## Stereoisomerism - same molecular formula - same connections - different arrangements ## Types of Structural Isomerism ### Chain Isomerism - 2 or more compounds with similar chemical formulas but distinct carbon atom arrangements in straight or branched chains - different parent chain length ### Simple reactions of organic compounds # Organic Compound - hydrocarbons # Combustion Reaction - alkanes, alkenes, and alcohols react with oxygen in the air resulting in an exothermic reaction that emits a significant quantity of energy # Incomplete Combustion - fuel burns in a limited supply of oxygen or air - CO, soot, and less energy release # Complete Combustion - fuel burns in a sufficient supply of oxygen - CO2 and H2O, releasing the maximum amount of energy # Addition Reaction - takes place to a hydrocarbon with multiple bonds # Condensation Reaction - reaction between two molecules forming a single molecule and release water molecules as a product - production of protein, amino acids combines during condensation reaction # Saponification Reaction - create soaps from fats - triglyceride - most simple & need strong base - strong base - Sodium hydroxide, Potassium hydroxide # Polymers - substance that is made of smaller molecules (monomers) that are chemically bonded together to form a large molecule or a macromolecule # Syndiotactic Polymers - SYNDIOTACTIC POLYMERS CONSIST OF PENDANT GROUPS ARRANGED IN ALTERNATING MANNER. AS SHOWN IN THE GIVEN EXAMPLE, TWO ADJACENT PENDANT GROUPS ARE ON OPPOSITE SIDES OF THE POLYMER BACKBONE. # Atactic Polymers - ATACTIC POLYMERS CONSIST OF PENDANT GROUPS RANDOMLY ORIENTED ON EITHER SIDE OF THE BACKBONE; IN SIMPLER WORDS, THESE REFER TO POLYMERS THAT ARE NEITHER ISOTACTIC NOR SYNDIOTActic # Step-Growth Polymerization - Step-growth polymers are those formed in a stepwise manner that polymer chains may grow separately without depending on other growing polymers. Growth of polymer chains occurs either via a series of addition or condensation reactions - Step-growth polymers are those formed in a stepwise manner that polymer chains may grow separately without depending on other growing polymers. Growth of polymer chains occurs either via a series of addition or condensation reactions # Tacticity FOR CHAIN-GROWTH POLYMERS, THE GROUPS ATTACHED TO THE ALKENE MONOMER CAN AFFECT THE PROPERTIES OF THE RESULTING POLYMER. THE RELATIVE POSITION OF THESE GROUPS, CALLED THE PENDANT GROUPS OF THE POLYMER, IS CALLED TACTICITY. BASED ON TACTICITY, CHAINGROWTH POLYMERS CAN BE CLASSIFIED AS ISOTACTIC, SYNDIOTACTIC, OR ATACTIC. TO UNDERSTAND THE DIFFERENCES BETWEEN THESE CLASSIFICATIONS, LET US CONSIDER THE POLYMER OF PROPYLENE. THE RESULTING POLYMER CHAIN CONSISTS OF METHYL (-CH3) GROUPS AS THE PENDANT GROUPS. # Isotactic Polymers ISOTACTIC POLYMERS CONSIST OF PENDANT GROUPS ARRANGED ON THE SAME SIDE OF THE POLYMER BACKBONE. IN THE GIVEN STRUCTURE OF POLYPROPYLENE, THE METHYL PENDANT GROUPS ARE ALL ON THE SAME SIDE-LOCATED TOWARDS THE OBSERVED. # Classification Based on Origins ## Natural Polymers - biochemical processes - found in living organisms - Protein Polymer Structure (murag normal lang) ## Synthetic Polymers - man made - from commercially available compounds - adhesives, fabrics, and plastic made products - Synthetic Polymer Structure (zigzag) ## Homopolymer - 1 type of monomer - polyester, nylon 6 nylon 11 - Polyester Polymer Structure (tung nay dako na circle) ## Heteropolymer - 2 or 3 more types of monomers - proteins insulin agar agar - peptidoglycans - insulin polymer structure (ambot unsa nani) ## Copolymer - copolymerization - alternating or random arrangement of the monomers # Tacticity FOR CHAIN-GROWTH POLYMERS, THE GROUPS ATTACHED TO THE ALKENE MONOMER CAN AFFECT THE PROPERTIES OF THE RESULTING POLYMER. THE RELATIVE POSITION OF THESE GROUPS, CALLED THE PENDANT GROUPS OF THE POLYMER, IS CALLED TACTICITY. BASED ON TACTICITY, CHAINGROWTH POLYMERS CAN BE CLASSIFIED AS ISOTACTIC, SYNDIOTACTIC, OR ATACTIC. TO UNDERSTAND THE DIFFERENCES BETWEEN THESE CLASSIFICATIONS, LET US CONSIDER THE POLYMER OF PROPYLENE. THE RESULTING POLYMER CHAIN CONSISTS OF METHYL (-CH3) GROUPS AS THE PENDANT GROUPS. # Isotactic Polymers ISOTACTIC POLYMERS CONSIST OF PENDANT GROUPS ARRANGED ON THE SAME SIDE OF THE POLYMER BACKBONE. IN THE GIVEN STRUCTURE OF POLYPROPYLENE, THE METHYL PENDANT GROUPS ARE ALL ON THE SAME SIDE-LOCATED TOWARDS THE OBSERVED.