EXAM 1 REVIEW September 24, 2010 Chemistry Learning Center UW Madison http://www.chem.wisc.edu/areas/clc/resource.htm Chapter 1 Basic Concepts of Chemistry 1
Be acquainted with the macroscopic and particulate perspectives of matter Understand differences between pure substances and homogeneous/heterogeneous mixtures 5. (2 pts) Explain what chemists refer to as a heterogeneous mixture and give a representative example (shall be a solid). 2
Know how to differentiate between elements, atoms, compounds, and molecules Know how to distinguish between physical and chemical properties and changes 3
Be able to define, and give examples of, intensive and extensive physical properties Understand relationship between mass, volume, and density 4
Know common metric prefixes (Table 2), especially mega-, kilo-, centi-, milli-, micro, and nano- Let s Review 5
Master dimensional analysis to convert between units Understand the difference between precision and accuracy 6
Be able to calculate experimental and percent error Understand scientific notation 7
Know how to use correct number of significant figures in calculations Chapter 2 Atoms, Molecules, and Ions 8
Know the basic composition of an atom Know how to determine the number of electrons, protons, and neutrons in an atom from the notation 9
Understand the difference between mass number, atomic weight, and atomic number Be familiar with the relative mass scale and the atomic mass unit 10
Recognize the meaning of isotopes Be able to calculate atomic weight from isotope abundances and isotopic masses 11
Determine isotopic abundance (or isotopic mass) from atomic weight and isotopic mass (or isotopic abundance) b. (3 pts) Using the data provided above, calculate the relative atomic mass of copper. Make sure to give the correct number of significant figures. Show your work. Know how to use the periodic table to find the atomic number and mass of any element 12
Understand the basic features of the periodic table (periods, groups, main group elements, transition elements, metals, nonmetals, metalloids) Know the basic properties of the key blocks (metals, nonmetals, metalloids) 13
Know the names and some key properties of the main groups (alkali metals,halogens, etc) Know the names and atomic symbols of the first 38 elements plus others from HW#1 14
Recognize that elements in the same group have similar chemical properties Molecular formula, condensed formula, structural formula, ball-and-stick model, and space- filling model C 4 H 10 CH 3 CH 2 CH 2 CH 3 15
Be able to predict whether a compound is ionic or molecular based on its constituent atoms Know the basic properties of ionic compounds Solids that arrange themselves into crystal lattices Held together by Coulombic forces Upon solvation in water breaks apart into constituent cations and anions 16
Know how to predict the charge of a main group element in an ionic compound based on its location in the periodic table 4. (2 pts) Which of the following two ionic compounds is expected to have the lower melting point and why? KCl (K and Cl belong to groups 1A and 7A, respectively) CaO (Ca and O belong to groups 2A and 6A, respectively) The melting point of... is lower because... Know the rules for naming ionic compounds and molecular compounds 1. (4 pts) Complete the table below by filling in the proper name or formula. Compound Proper Name FeCrO4 (NH4)2SO4 iron(iii)carbonate calcium phosphate 17
Remember the formulas, names, and charges of common polyatomic ions (Table2.4) +1 CHARGE -1 CHARGE -2 CHARGE -3 CHARGE ion name ion name ion name ion name NH + 4 ammonium H 2 PO - 3 dihydrogen phosphite HPO 2-3 hydrogen phosphite PO 3-3 phosphite H 3 O + hydronium H 2 PO - 4 dihydrogen phosphate HPO 2-4 hydrogen phosphate PO 3-4 phosphate HCO - 3 hydrogen carbonate CO 2-3 carbonate HSO - 3 hydrogen sulfite SO 2-3 sulfite HSO - 4 hydrogen sulfate SO 2-4 sulfate NO - 2 nitrite CrO 2-4 chromate NO - 3 nitrate Cr 2 O 2-7 dichromate OH - hydroxide CH 3 COO - acetate CrO - 2 chromite CN - cyanide MnO - 4 permanganate ClO - hypochlorite ClO - 2 chlorite ClO - 3 chlorate ClO - 4 perchlorate BrO - hypobromite BrO - 2 bromite BrO - 3 bromate BrO - 4 perbromate IO - hypoiodite IO - 2 iodite IO - 3 iodate IO - 4 periodate Know how to derive the name of a compound from its formula and vice versa 18
Understand the concepts of a mole and Avogadro's number Be able to calculate molar mass from molecular formula 19
Know how to convert between grams and moles using molar mass Know how to convert grams or moles to number of atoms using molar mass 20
Be able to calculate percent composition for a compound from its molecular formula 3. (3 pts total) Elemental copper can be obtained by heating Cu2S (chalcocite) in the presence of oxygen. The molar masses of the elements are: Cu = 63.546 g/mol and S = 32.066 g/mol.a. (2 pts) What is the mass percent of copper in Cu 2 S? b. (1 pt) How many grams of Cu 2 S must be used to produce 5.00 g of copper? Know how to determine the empirical formula from % composition 2. (6 pts total) Glucose, a simple sugar, is composed of 40.00% C, 6.71% H, and 53.28% O. The molar masses of the elements are: C = 12.011 g/mol, H = 1.0079 g/mol, and O = 15.9994 g/mol. a. (4 pts) What is the empirical formula of glucose? 21
Know how to determine the molecular formula from % composition and molar mass 2. (6 pts total) Glucose, a simple sugar, is composed of 40.00% C, 6.71% H, and 53.28% O. The molar masses of the elements are: C = 12.011 g/mol, H = 1.0079 g/mol, and O = 15.9994 g/mol. b. (2 pts) Knowing that its molar mass is 180.16 g/mol, what is the molecular formula of glucose? Chapter 3 Chemical Reactions 22
Understand the concept of conservation of matter as applied to a chemical reaction Know how to balance a chemical equation 23
Possess the ability to describe the concept of dynamic equilibrium Recognize that some reactions are product-favored and some are reactant-favored,and be able to provide examples for both types of reactions Identify each reaction or process as product-favored or reactantfavored? A. Ice melting at 0C B. Ice melting at 1C C. Wood burning D. Generating gasoline from car exhaust E. Apples oxidizing 24
Recognize what the solvent and solute(s) of a solution are Know how to distinguish between strong electrolytes, weak electrolytes, and nonelectrolytes 25
Understand what happens at the atomic level when an ionic solid dissolves Know how to use a solubility table to predict which ionic compounds dissolve and which ones form precipitates 26
Be able to write balanced equations, complete ionic equations, and net ionic equations Know the Brønsted-Lowry definition of acids and bases Acid is a proton donor Base is a proton acceptor 27
Memorize the acids and bases in Table 3.2 that derive from the common polyatomicions included in Table 2.4 (as specified in the lecture notes) Seven Strong Acids HCl - hydrochloric acid HNO 3 - nitric acid H 2 SO 4 - sulfuric acid HBr - hydrobromic acid HI - hydroiodic acid HClO 4 - perchloric acid HClO 3 - chloric acid Strong Bases LiOH - lithium hydroxide NaOH - sodium hydroxide KOH - potassium hydroxide RbOH - rubidium hydroxide CsOH - cesium hydroxide *Ca(OH) 2 - calcium hydroxide *Sr(OH) 2 - strontium hydroxide *Ba(OH) 2 - barium hydroxide Know which oxides form acidic solutions and which ones form basic solutions 28
Recognize which reagent is being oxidized, and which one is being reduced, during an oxidation-reduction reaction and know how to identify the oxidizing and reducing agents Leo the Lion Says Ger Reduction= GER= Gain of Electrons Oxidation = LEO= Loss of Electron OILRIG Oxidation is Loss=OIL Reduction is Gain=RIG Know the rules for assigning oxidation numbers and be able to apply them to ionic compounds 29
Know how to distinguish between precipitation, acidbase, gas forming, and oxidation-reduction reactions and be able to provide examples Chapter 4 Stoichiometry: Quantitative Information about Chemical Reactions 30
THE KEY TO STOICHIOMETRY Moles of what you want = Moles of Limiting Reagent X Coefficient of what you want Coefficient of Limiting Reagent Know how to use stoichiometric coefficients to determine mass relationships between reactants and products 31
Be able to identify the limiting reactant in a chemical reaction Know how to determine theoretical yield, actual yield, and percent yield 32
Use a chemical equation and other information to determine the composition of a reactant or product Know how to use the results from a combustion analysis to determine the empirical formula of substances such as CxHyOz and MxOy (where M is a metal) 33
Be able to calculate the molarity of a solution and use molarity in calculations Know how to prepare dilute solutions from a concentrated stock solution 34
Be able to calculate the ph of a solution containing a strong acid or strong base and know how to convert ph to hydronium ion concentration Know how the ph scale relates to acidity and basicity of a solution 35
Know how to solve stoichiometric problems using solution concentrations 36