CHEM FINAL EXAM Chemical Properties Change in composition Undergoes a chemical reaction Burns in air Releases a gas Dissociates breaks up in solution Physical Properties Describe nature Phase change solid to liquid Color Shape Density Melting Boiling Points Measurements SI System prefixes all of them are 1 and the m is the times to the negative MEGA M 10 6 1 megameter Mn 1 times 10 6m KILO k 10 3 1 kilometer km 1 times 10 3m DECI d 10 1 1 decimeter dm 0 1 m CENTI c 10 2 1 centimeter cm 0 01m MILLI m 10 3 1 millimeter mm 0 001 m MICRO u 10 6 1 micrometer um 1 times 10 6 m NANO n 10 9 1 nanometer nm 1 times 10 9 m PICO p 10 12 1 picometer pm 1 times 10 12 m Scientific Notation Significant Figures Left addition Right subtraction Example 0 000045 4 5 times 10 5 450000 4 5 times 10 5 Multiplication Division Answer must contain as many sig figs as value with least number of sig figs Example 1 39 2 7 3 753 real answer must be 3 8 since there is only one digit after the decimal Addition Subtraction Answer must contain same number of decimal places as value with fewest Example 1 39 2 7 4 09 real answer must be 4 1 since we are looking at the number of decimal places Formula NOT GIVEN ON TEST Density mass volume Density m p RT m molar mass Triangle mass density volume Volume L Density g ml Mass kg or g 1 mole 6 022 times 10 23 Na Atomic Structure Protons positive charge Electrons negative charge Neutrons no charge M X Z X name of the element Z atomic number M mass number When atom loses electrons it becomes a CATION positive charge When atom gains electrons it becomes a ANION negative charge Isoelectronic same number of electrons any atom ion Example 27 Al 3 Protons 13 number on top of Al periodic table Neutrons 27 13 14 Electrons 13 3 10 Isotopes Same of protons electrons different of neutrons and mass number Example N14 and N15 are both isotopes of nitrogen since they have the same number of protons but different mass numbers Atomic Mass M1 times A1 n M1 isotopic mass A1 abundance of isotope n number of isotopes Energy in E 0 energy is gained by the system and lost by the surrounding into a system done on the system positive in E 0 energy is lost by the system and gained by the surrounding out of a system done on the surrounding negative Change in e q w q heat and w kinetic energy Exothermic Endothermic H 0 exothermic enthalpy decreased and heat is released H 0 endothermic enthalpy increased and heat is absorbed Wavelength lowest to highest Gamma rays x rays ultraviolet visible light infrared rays micro radio Frequency lowest to highest Radio micro infrared rays visible light ultraviolet x rays gamma rays Formula E hc wave length E j photon Mass Smaller when wavelength bigger Mass Bigger when wave length smaller Terminology Ground state when electron is at the lowest energy orbital n 1 Example TI 2 Ar 4s 2 3d 2 lost 2s final answer Ar 3d 2 Excited state when electron is at a higher energy orbital n 2 3 4 etc Example Kr 5s 2 4d 9 5p 2 ground state Kr 5s 2 4d 10 5p 1 excited state answer In Absorb Emitted Largest release of energy exothermic emitted Smallest 2 1 Smallest release of energy Largest 1 2 Quantum s p d s 0 n 1 2 3 l 0 0 1 0 1 2 ml 0 1 0 1 2 1 0 1 2 s orbital l 0 ml 0 p orbital l 1 ml 1 0 1 d orbital l 2 ml 2 1 0 1 2 If l 0 than ml 0 Pauli s Exclusion Principle maximum of 2 electrons and they must have opposing spins 1 2 and 1 2 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 5 4p 6 5s 2 4d 5 5p 6 s orbital 1 box p orbital 3 boxes d orbital 5 boxes f orbital 7 boxes Bonding Ionic Bonding metal and nonmetal Covalent bonding nonmetal and nonmetal ClO hypo ite ClO 2 ite ClO 3 ate ClO 4 per ate Atomic Size Radius increasing Increasing Lattice Energy melting point Greatest charge more lattice Equal charge look at size atomic number smallest greater lattice Ionization Energy increasing Increasing Lewis Structure The Octet Rule The octet rule means that each element must have 8 electrons surrounding them Exception H hydrogen which is 2 B which is 6 and Be which is 4 From period 3 or higher do not always obey the octet rule Lone pairs are the dots Resonance Structure different ways to draw a Lewis structure Formal charge 3 valence electrons unshared valence electrons shared electrons Example P 5 periodic table 0 no dots around it 4 lines around it Best Lewis Structure is the one with 0 formal charge Bonds Energy Length and Strength When LENGTH increases STRENGTH AND ENERGY decreases DOUBLE BOND atoms are close together length is shorter than in a SINGLE BOND so the bond strength is greater TRIPLE BOND shorter and stronger than a DOUBLE BOND POLAR Bent v shaped trigonal pyramidal seesaw t shaped square pyramidal Farther apart more polar Molecular Geometry A central atom X atoms surrounding E lone pairs dots around it Electronegativity increasing F has the highest Increasing DIPOLE means NONPOLAR CIS SAME POLAR TRANS OPPOSITE NONPOLAR Hybrid Orbitals of electron groups 2 3 4 5 6 Hybrid orbital sp sp 2 sp 3 sp 3d sp 3d 2 SINGLE 1 0 sigma bond DOUBLE 1 0 sigma bond 1 pi bond TRIPLE 1 0 sigma bond 2 pi bond INTERMOLECULAR FORCES HINT NONPOLAR SYMMETRICAL POLAR NOT THE SAME IT IS NOT SYMMETRICAL 2 opposite charged atoms EX Mg 2 and SO 2 Ion Ion Ion Dipole Ion Polar Hydrogen Bonding H is bonded with N O or F Dipole Dipole Polar Polar Ion Induced Dipole Ion Nonpolar Dipole Induced Dipole Polar Non Polar Dispersion London Nonpolar Nonpolar STRONGEST WEAKEST Ion Ion Ion Dipole Hydrogen Bonding Dipole Dipole Ion Induced Dipole Dipole Induced Dipole Dispersion STRONGEST IMF HIGHEST MELTING BOILING POINT non polar molecules are equal check the greatest molecular weight strongest dispersion force Isomers exact same number of carbon but connected differently various shapes Hydrocarbons ALKANES single bond saturated ALKENES double bond 2 carbon atoms ALKYNES triple bond 2 carbon atoms Less than 10 hydrogen unsaturated Volume affected by temperature and pressure Gases Pressure Units 1atm 760 torr 760mmHg 1 01 times 10 5 Pa PV nRT P pressure V volume n moles T temp R 0 0821 atm mol FORMULA NOT GIVEN ON TEST Pressure force area Patm Pg h open ended the cylinder P1 V1 T1 P2 V2 T2 Ideal Gas Law Volume is not proportional to temperature BOYLES LAW constant T n Volume is proportional to temperature CHARLES LAW constant P …
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