CHEM 121: Final Exam Study Guide

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1 CHEM 121: Final Exam Study Guide Chapter 1 Know the Scientific method Know the definitions for hypothesis, scientific law, and scientific theory. Chapter 2 Length, mass, weight, volume - Know 1 cm 3 1 ml and 1 dm 3 1 L Significant figures and Scientific notation - Rounding, in addition or subtraction, in multiplication or division - Keep as many sig figs until final answer Scientific notation Metric system - Know the metric prefixes: kilo (k), deci (d), centi (c), milli (m), and micro (μ) - Be able to perform metric-metric conversions using these prefixes. Use the metric-english conversions provided (1 in cm; 1 lb=453.6 g; 1 qt=946 ml) Volume by calculation - V rectangular solid = length x width x thickness Volume by displacement Density: d = m V - Calculate density, mass, or volume - Identify what items sink or float given densities of liquids and solids. Temperature - Know the formulas for converting F-to- C or C-to- F and K-to- C or C-to-K Percentage: ratio of parts per 100 parts - Given amount of part and whole, calculate % - Use a given % to solve for part or whole Chapter 3 Know that matter is studied at the macroscopic, microscopic, particulate (molecular) levels Physical states of matter - Determine physical state of substances (solids, liquids, gases) given descriptions of volume, shape, particles moving, etc. Classify properties and changes as physical or chemical - Know terms for changes of state: - Melting, freezing, vaporizing, condensation, sublimation, deposition Classification of matter Given examples, determine which are elements, compounds, or mixtures Given molecular-level images, determine which are elements, compounds, or mixtures and solids, liquids, or gases Distinguish between homogeneous and heterogeneous mixtures Chemical reaction: - reactants: starting materials - products: substances produced in reaction CHEM121 Final Exam Study Guide page 1 of 11

2 Chapter 3 (Continued) kinetic energy (KE): energy associated with an object s motion - Faster objects have higher KE. - Know the relative kinetic energy of solids, liquids, and gases potential energy (PE): energy due to its position or composition (chemical bonds) heat: energy is transferred from a hotter substance to a cooler substance Identify what lost heat and gained heat given different scenarios. Endothermic versus Exothermic changes: endothermic: a change requiring energy exothermic: a change that releases energy Endothermic versus Exothermic changes: Determine if a physical change or chemical change is exothermic or endothermic. Law of Conservation of Mass - Solve problems conserving mass. Law of Conservation of Energy - Know 6 forms of energy: heat, chemical, light, electrical, mechanical, and nuclear Chapter 4 Know the main points of John Dalton s Model, what was later proven wrong and why KNOW people and discoveries associated with the discovery of protons, neutrons, electrons Know Rutherford s Alpha Scattering Experiment and what was determined from it (atomic nucleus, atom mostly empty space, relative size of atom relative to its nucleus) Subatomic particles proton (p + ): +1 charge, inside nucleus neutron (n): neutral, inside nucleus electron (e ): 1 charge, outside nucleus Electrostatic force: force resulting from a charge on particles - Objects w/ like charges repel one another. - Objects w/ unlike charges attract each other. Know definitions of isotope, atomic mass Atomic notation: mass number = A E = element symbol atomic number = Z mass # (A): # of protons + # of neutrons atomic # (Z): # of protons=# of electrons Determine # of protons, neutrons, and electrons for any given isotope or ion. Know the atomic mass reported on the Periodic Table is the weighted average of all naturally occurring isotopes for that element. Use the Periodic Table to identify the most abundant isotope of any element given its naturally occurring isotopes. Use the Periodic Table to identify those elements whose naturally occurring isotopes are all radioactive and unstable. Determine the number of atoms of an element in a compound given the chemical formula. CHEM121 Final Exam Study Guide page 2 of 11

3 Chapter 4 (Continued) The Periodic Table column = group, family row = period, series Representative Elements: A Group Elements Group IA: alkali metals (except H) Group IIA: alkaline earth metals Group VIIA: halogens Group VIIIA: noble gases Transition Metals/Elements: B Group Elements Inner Transition Elements: - Elements in lanthanide and actinide series Metals, nonmetals, and semimetals: - Know properties of metals and nonmetals - Location on Periodic Table and properties Know which elements exist as solids, liquids, gases at room temperature (25 C) Know the names and symbols for all elements included in Ch. 4 notes, p. 11, Ti (titanium), Sr (strontium), and uranium (U). Spelling counts! Chapter 9 Wavelength (λ) is inversely related to frequency (ν) and energy (E): As λ ν, Ε or As λ ν, Ε Electromagnetic Spectrum: continuum of radiant energy gamma (γ) rays to radio waves Know the people and ideas associated with the Classical Model of Matter Dalton, Thomson, Rutherford, Maxwell Planck and Quantum Theory proposed energy is absorbed and emitted as bundles = quanta single bundle of energy = quantum Einstein and the Photoelectric Effect Experimental evidence for light existing as particles = photons Bohr Model of the Atom Electrons move in quantized orbits called energy levels around nucleus Know if energy is gained or lost for e - s moving from one energy level to another. ground state: e - s in lowest E level(s) Atomic Orbital Shapes reflect the probability density for an electron in a given orbital As principal energy level (n=1, 2, 3, ) increases, the orbital size increases. Know energy levels and sublevels (s, p, d, f) Know the general shapes for s and p orbitals. Be able to write electron configurations for any neutral atom for elements #1-20. Write using full notation and core notation (Noble Gas abbreviation) Know Representative Elements usually form ions that are isoelectronic with a Noble Gas Define atomic radius, ionic radius, and ionization energy. Know Periodic Trends for Atomic radius and Metallic Character - Increase down a group - Decrease left to right across a period Ionization Energy: - Decreases down a group - Increases left to right across a period - Opposite trend as atomic radius since IE as atomic radius CHEM121 Final Exam Study Guide page 3 of 11

4 Chapter 10 core electrons: electrons belonging to filled electron shells valence electrons: outermost electrons group number for each element is equal to the number of valence electrons it has Determine the formulas for the ions formed by Representative (Main Group) Elements using a Periodic Table. electronegativity (EN): ability of an atom in a bond to draw electrons to itself Know F is most electronegative, further away from F, less electronegative an atom. ionic bond: electrostatic attraction between cations and anions in an ionic compound covalent bond: sharing of electrons between two nonmetal atoms polar covalent: unequal sharing of e s by 2 atoms with different EN values nonpolar covalent: equal sharing of electrons by two atoms with equal EN Draw dipole arrows to indicate which atom in a bond is more electronegative bond length: distance between nuclei of 2 bonded atoms Know the how bond length is related to bond strength shorter the bond, the stronger the bond single bonds are the longest and weakest double bonds are shorter and stronger triple bonds are the shortest and strongest Metallic Bond: - Metals exist as nuclei in a sea of electrons special properties of metals resulting from electrons freedom to move around Be able to identify a bond as ionic, metallic, polar covalent, or nonpolar covalent octet rule: atoms bond such that each has 8 electrons, except H only needs 2 electrons. Draw Lewis Structures for Molecules & Polyatomic Ions The central atom will be indicated. Know H atoms are bonded to the O atoms in ternary oxyacids. Molecular Shapes and Polarity Use Lewis structure and to get 3D shape and bond angles: - AX 2 linear AX 3 trigonal planar AX 4 tetrahedral AX 2 E bent <120 - AX 3 E trigonal pyramidal < AX 2 E 2 bent <109.5 Use electronegativity to determine if a bond is polar or nonpolar covalent. Given a molecule, determine if it s polar or nonpolar using the 3D shape and dipoles. Like dissolves like rule - Polar substances will mix and dissolve in one another, and nonpolar substances will mix and dissolve in one another. - Polar substances will NOT mix and dissolve in nonpolar substances and vice versa. - Use the polarity of substances to determine which liquids are miscible and which solids are soluble in a given solvent. Hydrocarbon (molecules containing only C and H atoms) are always nonpolar. Alcohols (molecules with a hydroxyl OH group) are always polar. CHEM121 Final Exam Study Guide page 4 of 11

5 Chapter 12 Intermolecular Forces (IMF s): attraction between 2 different molecules in a liquid or solid Identify the type of intermolecular force for a molecule as London/dispersion forces, dipoledipole forces, hydrogen bonding, or ion-diple forces Know that hydrogen bonds are the strongest type of intermolecular force, dipole-dipole forces are the next strongest, and London forces are generally the weakest. Recognize that London forces increase with more electrons use size to determine relative number of electrons for different molecules. Know the terms: evaporation, boiling point, vapor pressure, volatile, nonvolatile Recognize how IMF s influence vapor pressure and boiling point. Given different substances, determine which has the highest boiling point based on IMF s. Given a bond or intermolecular force, identify it a polar covalent, nonpolar covalent, ionic, metallic, ion-dipole forces, London/dispersion forces, dipole-dipole forces, or hydrogen bonding. Know ionic and covalent bonds are stronger than all intermolecular forces, even H bonds. Given its formula, classify a solid as ionic, molecular, metallic or network covalent. Know the unique properties of ice resulting from the hydrogen bonds between molecules in the solid (e.g. density of solid versus liquid, why snowflakes have hexagonal symmetry, etc.). Know the regions and features of a Heating/Cooling Curve. Chapter 5 ionic compound: a compound consisting of metal cations and anions held together by ionic bonds molecule (or molecular compound): a compound consisting of nonmetal atoms held together by covalent bonds Identify a compound as an ionic compound or molecule given its name or chemical formula. Diatomic elements: H 2, N 2, O 2, F 2, Cl 2, Br 2, I 2, Naming cations: - Group IA, IIA, Al, Ag, Zn, Cd: element name + ion - All other metals - Stock system: - element name (charge in Roman #s) + ion Naming anions: nonmetal stem + "-ide" + ion Know the ions formed by the A Group or Representative elements using the Periodic Table. Know the names and formulas of POLYATOMIC IONS included the Chapter 5 lecture notes! Naming ionic compounds: - cation name + anion name - IA, IIA, Al, Ag, Zn, Cd don't need Roman #s - All other metals need Roman #s Nomenclature for Ionic Compounds: - Given the formula of a compound, determine its name, or vice versa. CHEM121 Final Exam Study Guide page 5 of 11

6 Chapter 5 (Continued) Naming binary molecular compounds: - Use Greek prefixes when more than one atom of an element is present. - Know names for NH 3, CH 4, and H 2 O 2, or given the name, write the formula. Naming binary and ternary acids: H('s) + "-ide" ion "hydro ic acid" - e.g. Cl - = chloride ion HCl (aq) = hydrochloric acid H('s) + "-ate" ion " ic acid" - e.g. SO 4 2- = sulfate ion H 2 SO 4 (aq) = sulfuric acid H('s) + "-ite" ion " ous acid" - e.g. NO 2 - = nitrite ion HNO 2 (aq) = nitrous acid Chapter 6 Avogadro's number = 6.022x10 23 Molar Mass - Be able to get molar masses (in g/mol) for atoms and compounds Standard temperature & pressure (STP): T=0 C and P=1.00 atm Molar volume: 1 mole of any gas at STP occupies 22.4 L Carry out Mole calculations using - Avogadro's Number (N): x Molar masses of atoms and compounds - Molar volume at STP: 22.4L/mole for a gas Percentage composition: - Find percent composition of all elements in a compound given its formula or name. Chapter 7 Writing Chemical Equations: reactants vs. products Be able to balance chemical equations. Change coefficients, NEVER subscripts to get the same # on both sides of equation. Classify reaction types & balance equations: - Combination - Decomposition - Single-replacement - Double-replacement/precipitate - Double-replacement/Neutralization - Combustion Reactions - If a reaction is a redox reaction or not Be able TO PREDICT PRODUCTS given a set of reactants and Solubility Rules and the Activity Series for the following TYPES of REACTIONS: Single-replacement reactions solid metal + metal solution/acid solid metal + H 2 O(l) Combustion reactions C x H y + O 2 CO 2 (g) + H 2 O (g) C x H y O z + O 2 CO 2 (g) + H 2 O (g) Acid-Base Neutralization Reactions HX + MOH water + salt HX + MHCO 3 water + CO 2 + salt HX + MCO 3 water + CO 2 + salt CHEM121 Final Exam Study Guide page 6 of 11

7 Chapter 7 (Continued) Strong, Weak and Non-Electrolytes strong electrolyte: breaks up completely many ions present to conduct electricity e.g. strong acids & bases, aqueous salts weak electrolyte: breaks up to small degree only few ions present to conduct electricity e.g. weak acids & bases, insoluble salts nonelectrolyte: a molecular compound that forms molecules in water no ions does not conduct electricity Acids and Bases as electrolytes The list of strong acids will be given. All other acids are weak. Strong acids and bases break up completely to produce many H + or OH - ions. Weak acids and bases barely break up, producing on a few H + or OH - ions. Representing Strong and Weak Electrolytes Recognize soluble ionic compounds and strong acids break up into ions with a physical state of aqueous, (aq). All solids, liquids, gases, and weak acids are shown as compounds. Chemical Equations & Net Ionic Equations Chemical Equation: compounds shown intact Complete/Total Ionic Equation: shows strong electrolytes as ions Spectator Ions: ions that remain unchanged during a reaction Net Ionic Equation: Shows what substances change in a chemical reaction Be able to write Total and Net Ionic Equations. Chapter 8 Stoichiometry: Use mole-to-mole ratios to relate and calculate the amounts of reactants and/or products in a chemical reaction Calculate the mass or volume of a reactant or product given the amount of another reactant or product and the balanced chemical equation. Yields of Reactions theoretical yield: amount of product predicted using the balanced equation when limiting reagent is used up (can be calculated) actual yield: amount of product one actually obtains (generally given in the problem) Percent yield = actual yield theoretical yield 100% CHEM121 Final Exam Study Guide page 7 of 11

8 Chapter 11: Gases Know the properties of gases. Know definitions: vacuum, gas pressure, atmospheric pressure, compressibility Recognize that atmospheric pressure decreases with altitude. Gas pressure and Atmospheric pressure Convert between units of pressure: 1 atm 760 torr 760 mmhg = 14.7 psi Know how changes in volume, temperature, and number of particles affect gas pressure. Given 2 sets of conditions, solve problems P1 V1 P2 V2 using =, including canceling T1 T2 variables that stay the same to simplify. Recognize that temperatures (T s) must be in Kelvins. Solve for a variety of problems involving gases Use ideal gas law (PV=nRT) to solve for P, V, L atm n, or T. R= will be given. mol K Standard Temperature & Pressure (STP): T= 0 C and P=1.00 atm Molar volume of a gas at STP = 22.4L/mol Solve for gas density or molar mass at STP. Identify an unknown elemental gas given its gas density at STP by solving for molar mass. Dalton s Law of Partial Pressure: Use Dalton s Law (P total = P 1 + P 2 + P 3 + ) to solve for the total pressure or the partial pressure of one gas in a mixture of gases. Recognize that when a gas is collected over water, the total pressure is due to water vapor and the gas. Chapter 13: solution: uniform mixture of two or more substances as atoms, ions, or molecules a solute dissolved in solvent Know how temperature affects the solubility of gases and solids in solution. Know how gas pressure affects the solubility of gases in solution. Recognize what occurs at the molecular level when a solute dissolves in water. Recognize what can be done to increase the rate of dissolving: heating solution, stirring solution, grinding solute into smaller particles Know the definitions for unsaturated, saturated, and supersaturated Use Like dissolves like Rule and the Solubility Rules to predict what substances are soluble/insoluble in or miscible/ immiscible with water or other solvent Mass Percent Concentraton (M/M%): mass of solute M/M%= mass of solution 100% Molarity (Molar moles of solute Concentration)= liters of solution Weight/Volume Percent (% w/v) mass of solute % w/v = 100% ml of solution CHEM121 Final Exam Study Guide page 8 of 11

9 Chapter 13 (Continued) Dilution Equation: M 1 V 1 = M 2 V 2 Be able to solve for M 2 in terms of molarity, mass percent conc., or percent w/v. Account for dilution with DI water for V 2 Molarity and Mass Percent Conc. Calculations Solve for amount of solute, solvent, or solution given mass percent concentration, molarity, etc. Use molarity and volume to solve for moles Solve problems involving molarity and mass percent concentration using unit analysis. Know definitions for: diffusion, semi-permeable membrane, osmosis, isotonic, hypertonic, hypotonic, and osmotic pressure. Chapter 14 Know properties of acids and bases Know the Arrhenius and Brønsted-Lowry (B-L) definitions for acids and bases Given an acid-base reaction, - Classify each reactant as an Arrhenius and/or a Bronsted-Lowry acid or base - Indicate the conjugate acid-base pairs. - Note that conjugate acid-base pairs differ only by a H + ion. Strong and Weak Acids and Bases Know strong acids ionize completely to produce many H + (or H 3 O + ) ions. Know strong bases dissociate completely to produce many OH ions. Classify a substance as a strong or weak acid or strong or weak base given its chemical formula and %ionization or % dissociation Recognize water rarely ionizes to form ions It does not conduct electricity. Ion-product or dissociation constant for water at 25 C, K w =[H + ][OH ] =1.0x10 14 acidic solutions: [H 3 O + ] > [OH ], ph < 7 basic solutions: [OH ] > [H 3 O + ], ph > 7 neutral solutions: [OH ] = [H 3 O + ], ph = 7 Use ph to classify a substance as neutral, strongly or weakly acidic, strongly or weakly basic. Calculate ph or poh using [H + ]=10 ph and [OH ]=10 poh ph + poh = K w =[H + ][OH ] =1.0x10 14 Know definitions for indicator, standard solution, titration, and endpoint Buffer Systems Know a buffer system consists of a weak acid and its conjugate base. Know how the buffer system (weak acid/ conj. base) can neutralize small amounts of H + or OH, so a buffered solution can maintain its ph. Know how blood is buffered to keep its ph between given its buffer system: H + (aq) + HCO - 3 (aq) H 2 CO 3 (aq) CO 2 (g) + H 2 O(l) Define acidosis, alkalosis, and hyperventilation Use Le Châtelier's Principle to explain how changes in CO 2 levels can cause acidosis or alkalosis. CHEM121 Final Exam Study Guide page 9 of 11

10 Chapter 15 Distinguish between spontaneous and nonspontaneous processes. Know the definitions for reaction rate, activation energy (E act ), catalyst, enzyme. Know how a catalyst lowers the activation energy for a reaction by providing an alternative pathway for bond breaking and bond formation. Know Collision Theory, and recognize the activation energy and collision geometry requirements for a chemical reaction to occur. Be able to identify and explain the three factors that increase the rate of chemical reactions. At equilibrium, the rates of forward and reverse reactions are equal. Reactant and product concentrations are constant (not changing) but do not have to be equal. Endothermic and Exothermic Reactions Know definitions for endothermic and exothermic reactions. Know relative energy of reactants and products based on the strength of their bonds. Recognize if energy is released/absorbed, based on temperature changes for the surroundings following reaction. Reaction Energy Diagrams Recognize the different parts of a reaction energy diagram, including the energy of reactants and products, the heat of the reaction (ΔH), the activation energy (E a ) for the forward and reverse reactions, and the effects of a catalyst. Use a reaction energy diagram to classify a reaction as endothermic or exothermic. Know Le Chatelier's Principle and apply it to systems at equilibrium to solve problems involving changes in concentration of reactants or products or temperature changes. Chapter 16 Be able to determine oxidation numbers for all the elements/atoms/ions in a chemical equation. Use oxidation numbers to determine which reactant was oxidized (served as reducing agent) and which reactant was reduced (served as oxidizing agent) Write half-reactions to determine the # of electrons transferred. CHEM121 Final Exam Study Guide page 10 of 11

11 Chapter 17: Know the atomic notation for the following: protons, neutrons, electrons, alpha particles, beta particles, gamma rays, and positrons. Complete and balance nuclear equations, including writing complete nuclear equations for alpha, beta, positron, and gamma emissions. Know the terms: parent and daughter nuclide Write and balance nuclear equations given the radioactive decay/emission and the parent or daughter nuclide Solve problems involving half-life. You will be given a CHEM 121 Periodic Table with the Polyatomic Ions, the Solubility Rules, the Activity Series, and the List of Active Metals. Part of the exam will be Scantron, so bring a #2 pencil and a basic 100-item Scantron form (Form no. 882-E) with choices A through E. CHEM121 Final Exam Study Guide page 11 of 11

CHEM 130 Final Review

CHEM 130 Final Review Chapter Chp 1 Chemistry Define Introduction Scientific approach Describe Theory, natural law Distinguish between theory & law Chp 2 Scientific notation Conversions between standard