CHEM 1315 Exam 1 Study Guide
CHEM 1315 Exam 1 Study Guide CHEM 1315 - 002
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This 6 page Study Guide was uploaded by Christa Boettiger on Sunday February 7, 2016. The Study Guide belongs to CHEM 1315 - 002 at University of Oklahoma taught by Fares Z Najar in Spring 2016. Since its upload, it has received 50 views. For similar materials see General Chemistry in Chemistry at University of Oklahoma.
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Date Created: 02/07/16
CHEM 1315 Exam 1 Study Guide Unit 0 (Appendix & Section 1.3, 2.3, 2.5, 2.6, 2.7) Know how to perform unit conversions Understand scientific notation SI Units o Length = meter (m) o Mass = Kilogram (kg) o Time = second (s) o Temperature = Kelvin (K) o Amount = mole (mol) Conversion Factors to Know: o 1kg = 1000g o 1g = 1000mg o 1L = 1000mL o 0 C = 273.15 K o 1 mol = 6.022 x 10 23atoms o 1mL = 1cm 3 o Converting F to C 5 ( 9 ) x (__ F – 32) = C o Converting C to F ( 9 x __ C ) + 32 = F 5 o Converting Celsius to Kelvin ___ C + 273.15 = K Unit 1 (Chapters 1 & 2) Element: Most simple form, cannot be chemically broken down into a simpler substance ex: Hydrogen (H) o Solid: Definite shape and volume, least kinetic energy, cannot be compressed Solids and liquids of the same substance have close to the same density o Liquid: Definite volume but NOT definite shape, cannot be compressed o Gas: No definite volume or shape, least dense, most kinetic energy, can be compressed Compound: a molecule composed of two or more elements in a fixed definite proportion ex: Water (H2O) o Can only be separated by a chemical reaction Mixture: Substance composed of two or more parts of varying proportions o Homogeneous: Same throughout ex: salt water, air o Heterogeneous: Can differentiate the parts ex: package of skittles Physical Change: Only alters the state or appearance (atoms/molecules do not change) Chemical Change: Alters the composition (atoms rearrange) Bonds: o Ionic: One atom must gain or lose an electron Metals and non metals often form ionic bonds Metals gain an electron Non metals lose an election o Covalent: Atoms share an electron Scientists: o Leucippus o Newton Believed atoms were invisible particles in air o Antoine Lavoisier Law of Conservation of Mass (1789) In a chemical reaction, matter is not created nor destroyed o Joseph Proust Law of Definite Proportions: All samples of a given compound, will have the same proportion of their elements (ex: a water molecule will always have 2 H and O) o John Dalton Law of Multiple Proportions: When two elements form two different compounds, the masses of element A that combine with 1g of element B can be expressed as a ratio Atomic Theory 1. Each element is made of atoms 2. All atoms of a given element have the same mass and other properties that distinguish them from other atoms 3. Atoms combine in whole number ratios and form compounds 4. Atoms of one element cannot change into atoms of another element (only can be bound together) o Robert Millikan Oil drop experiment Determined the charge of an electron (1.602x10 -19 Coulombs) Found mass of an electron = 9.10x10 g -28 o JJ Thomson Cathode Ray experiment Found atoms are composed of sub atomic particles “Plum Pudding Model” o Ernest Rutherford Gold foil experiment Discovered atoms have a nucleus o James Chadwick Discovered neutrons Atoms: o Protons: Positively charged particles in an atom, inside nucleus o Electrons: Negatively charged particles in an atom, outside nucleus o Neutrons: Neutrally charged particles in an atom, inside nucleus o Atomic Mass Unit (amu): 1/12 the mass of a carbon atom. The mass of a proton and neutron are 1 amu o Atomic Number: The number of protons and neutrons in an atom o Mass Number: Sum of an atoms protons and neutrons o Ions: Atoms that are positively or negatively charged due the gain or loss of an electron Cations: Positively charged ions (lose an electron) Ex: Li + - Anion: Negatively charged ions (gain an electron) Ex: Fl Isotopes: o A variation of an atom in which it still has the same number of protons, but the number of neutrons varies o Atoms will have a different number of naturally occurring isotopes o Average Atomic Mass: the number of isotopes that exist for the element multiplied by the % abundance of each isotope o Natural Abundance: the percentages of each variation of isotope for a particular atom Avogadros Number o One mole of anything is 6.022 x 10 23 23 o A mole of an element contains 6.022 x 10 atoms of that element o The lighter the atom the less mass in one mole of atoms o Atomic Weight 1) Multiply decimal fraction of each isotope by the mass number 2) Add together Ex: 23.99 amu with 78.99% abundance = (23.99 x 0.7899) Unit 2 (Chapters 3 & 4) Schrodinger’s cat: An experiment in which scientist Erwin Schrodinger claimed that when covered up, his cat in a gaseous chamber could be both alive AND dead since until its true state was discovered. Relates to how light is both particle and wave Wave: o Amplitude: vertical height of a crest Determines the brightness of a light o Wavelength (): The distance between two crests (units = meters) Determines the color of light o Frequency (): The number of cycles a wavelength passes over a given time (units = s or Hertz (Hz) c o Equation: v= (frequency = speed of light/ wavelength) λ Speed of light is 3.00 x 10 m/s 1nm = 10 m (convert wavelength from nanometers to meters) Particle: o Photoelectric Effect: Observation that metals will emit electrons when light of a certain frequency shines on it o The higher the frequency the greater the energy (more damaging) of each photon o Photon: a stream of light particles o Equations: Planck’s constant is h = 6.626 x 10 -34J s hc E= (energy of one photon) or E=hv (if given λ frequency) Atomic spectroscopy: The study of electromagnetic radiation absorbed and emitted by atoms o Atoms absorb energy and emit is as light o Each element emits light of a different color combination Bohr Model o Electrons move in a circular orbit around the nucleus of an atom o Electrons can move between energy levels When it drops energy levels (ex: from n = 2 to n = 1) it emits light The distance dropped determines the color (n = 5 vs n = 2 to n = 1) o Lowest energy state = ground state (ex: n = 1) o Higher energy state = excited state (ex: n = 2 or more) Brogdile Relation: h -34 o λ= mv (h = 6.626 x 10 ) o Uncertainty Principle: We cannot know an electrons position and velocity at the same time The more accurately we know the position the less we know of the velocity and momentum (and vice versa) o Exclusion Principle: Two neutrons cannot occupy the same quantum state at the same time Quantum Mechanics: Mathematical model in which the wave and particle nature of matter are used together o When electrons release energy the change in energy is NEGATIVE o When electrons absorb energy the change in energy is POSITIVE Orbitals o Describe the distribution of electron density in space (the probability of where an electron is) o Orbitals with the same value of n form a shell o Different orbital types within a shell are subshells 2 o The total number of orbitals in a shell is n o Quantum Numbers: n = principle quantum number The energy level of the orbital Size of the orbital (a larger n = farther from the nucleus) l = angular momentum defines the shape of the orbital Value 0 1 2 3 of l Type s p d f m l magnetic quantum number describes the placement of the orbital on any energy level there can be 1 s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals m s spin quantum number describes the electrons magnetic field always +/- ½ o Pauli’s Exclusion Principle No two electrons in the same atom can have the same four quantum numbers Periodic Table of Elements o Organization Groups = vertical columns Periods = horizontal rows Diatomic Elements (exist as 2 atoms) Br 2 I2, N2, C2 , 2 , 2 , 2 When atoms lose an electron their charge becomes more positive Noble Gases: elements on the far right side that fill an entire energy level o Metals (on left of periodic table) Tend to lose electrons during a chemical change (form + ion) Most elements are metals High thermal conductivity High electrical conductivity Malleability Ductility o Non Metals (on the right of the periodic table) Atoms tend to gain electrons during a chemical change (form – ion) Brittle Powdery Solids or gases o Metalloids Have properties of both metals and non metals Electron Configuration 5 o Ex: 4p (4 is the energy level, p is the orbital letter, 5 is the number of electrons on that energy level) o The total number of electrons is equal to the sum of the superscripts o S orbitals can hold 2 electrons, p orbitals can hold 6, d orbitals can hold 10, and f orbitals can hold 14 o A half full level is better than partially full o Effective nuclear charge (Z ) eff
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