CHEM FINAL EXAMChemical Properties-Change in composition-Undergoes a chemical reaction-Burns in air-Releases a gas-Dissociates (breaks up) in solutionPhysical Properties-Describe (nature)-Phase change (solid to liquid)-Color, Shape, Density-Melting & Boiling PointsMeasurementsSI 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 10^6mKILO k 10^3 1 kilometer (km) = 1 times 10^3mDECI d 10^-1 1 decimeter (dm) = 0.1 mCENTI c 10^-2 1 centimeter (cm) = 0.01mMILLI m 10^-3 1 millimeter (mm) = 0.001 mMICRO u 10^-6 1 micrometer (um) = 1 times 10^-6 mNANO n 10^-9 1 nanometer (nm) = 1 times 10 ^-9 mPICO p 10^-12 1 picometer (pm) = 1 times 10^-12 mScientific Notation & Significant Figures.Left additionRight subtractionExample: 0.000045 4.5 times 10^-5 450000 4.5 times 10^5Multiplication & 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/volumeDensity= m(p)/RT m=molar massTriangle: Volume = LDensity = g/mlMass = kg or g1 mole = 6.022 times 10^23 (Na)Atomic StructureProtons: positive chargeElectrons: negative chargeNeutrons: no chargeM XZmassvolumedensityX name of the elementZ atomic numberM 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 = 10Isotopes-Same # of protons/electrons, different # of neutrons and mass numberExample: 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) nM1 isotopic massA1 abundance of isotopen number of isotopesEnergy 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 energyExothermic/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 raysMass Smaller when wavelength biggerMass Bigger when wave length smaller Terminology Ground state: when electron is at the lowest energy orbital n= 1Example: 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 etcExample: [Kr] 5s(2), 4d(9), 5p(2) (ground state) [Kr] 5s(2), 4d(10), 5p(1) (excited state) answer: InAbsorb Emitted Largest release of energy (exothermic = emitted) = Smallest 2 1Smallest release of energy = Largest 1 2Formula E = hc/(wave length)E j/photonQuantum # s p d s = 0 n 1 2 3l 0 0,1 0,1,2ml 0 -1,0,1 -2,-1,0,1,2s-orbital: l=0 ml = 0 p-orbital: l=1 ml=-1,0,1d-orbital: l=2 ml=-2,-1,0,1,2** If l=0 than ml=0Pauli’s Exclusion Principle -maximum of 2 electrons and they must have opposing spins (+1/2 and -1/2)s-orbital 1 boxp-orbital 3 boxesd-orbital 5 boxesf-orbital 7 boxes1s(2) , 2s(2), 2p(6), 3s(2), 3p(6), 4s(2), 3d(5), 4p(6), 5s(2), 4d(5) 5p(6) BondingIonic Bonding: (metal and nonmetal)Covalent bonding: (nonmetal and nonmetal) ClO^- hypo ( ) iteClO^-2 iteClO ^-3 ateClO ^-4 per ( ) ateAtomic Size/Radius increasing IncreasingLattice Energy = melting point (Greatest charge more lattice)(Equal charge look at size atomic number, smallest = greater lattice)Ionization Energy increasingIncreasingLewis 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 + ½ # 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 decreasesDOUBLE 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.Molecular GeometryA central atomX atoms surroundingE lone pairs (dots around it)POLAR Bent (v-shaped), trigonal pyramidal, seesaw, t-shaped, square pyramidal.Farther apart more polarElectronegativity increasingIncreasing**F has the highest.DIPOLE means NONPOLARCIS SAME POLARTRANS OPPOSITE NONPOLARHybrid Orbitals# of electron groups 2 3 4 5 6Hybrid orbital sp sp^2 sp^3 sp^3d sp^3d^2SINGLE 1 = 0(sigma) bondDOUBLE 1 = 0(sigma) bond / 1 = pi bondTRIPLE 1= 0(sigma) bond / 2 = pi bondINTERMOLECULAR FORCESHINT:NONPOLAR SYMMETRICALPOLAR NOT THE SAME, IT IS NOT SYMMETRICALIon-Ion(2 opposite charged atoms) EX: Mg^2+ and SO^2-Ion-DipoleIon & PolarHydrogen BondingH is bonded with N, O or FDipole-DipolePolar & Polar Ion Induced-DipoleIon & NonpolarDipole Induced-DipolePolar & Non Polar Dispersion
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