4) Convert: a) 10 m = km b) 500 g = mg c) 250 ml = L

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1 Data Analysis 1) Define: a) Accuracy b) Precision 2) The actual density of water is 1.00 g/ml Fred Wilma Barney Trial g/ml 0.88 g/ml 1.00 g/ml Trial g/ml 1.07 g/ml 1.01 g/ml Trial g/ml 1.03 g/ml 0.99 g/ml Average 1.12 g/ml 0.99 g/ml 1.00 g/ml Fred s data is. Wilma s data is. Barney s data is. (Fill ALL blanks) a. both accurate and precise b. neither accurate nor precise c. accurate but not precise d. precise but not accurate 3) Indicate the number of significant figures: a) b) c) d) ) Convert: a) 10 m = km b) 500 g = mg c) 250 ml = L 5) Perform the following operations. Record your answers to the correct number of significant figures. a) 5.00 cm x cm = b) 5.0 cm + 12 cm = c) 25.0 g 5.0 ml = d) 10.0 ml 7.5 ml = e) (2.5 x 10 2 cm) x (1.00 x 10-2 cm) x (2.0 x 10 1 cm) = f) (2.7 x 10-7 )-(1.3 x 10-9 ) = 6) You conduct an experiment in which you measure the density of water to be g/ml. The accepted value for the density of water is g/ml. Calculate the percent error: Atomic Structure 7) Fill in the table: Isotope Symbol Atomic Mass Mass # Atomic # # of protons # of neutrons # of electrons Hydrogen amu U 8) Isotopes are atoms of the same element, which have the same number of but a different number. 9) Isotopes chlorine 34, chlorine-35 & chlorine-36 have the same number of. 10) Draw diagrams (in the 1st row) and discuss IN DETAIL the major discoveries and important experiments for the development of the atomic model (in the 2nd row). Dalton Thompson Rutherford Bohr 11) What did Milikan s oil-drop experiment show? Page 1 12/10/2014

2 12) An unknown element has four naturally occurring isotopes shown below. Calculate the element s average atomic mass and use the periodic table to determine its identity. Show all work. Percent abundance Mass (amu) 4.35 % % % % The mass spectrum for chlorine is on the right: 13) Explain why there are two separate groups of peaks. 14) State what causes each of the 5 lines. Formulas and Chemical Reactions: 15) Identify all seven diatomic molecules: 16) Write the formulas and charges for the following polyatomic ions: hydroxide: sulfate: phosphate: ammonium: nitrate: carbonate: 17) Predict the charge of the following ions: Mg, Na, and Al. 18) For the following Ionic names, write the chemical formula or the chemicals name: a) copper (II) oxide b) calcium carbonate c) potassium nitrate d) ammonium chromate e) gold (III) iodide f) zinc phosphide g) lithium sulfate h) Na 2 SO 4 i) Al 2 O 3 j) SnO k) K 2 S l) (NH 4 ) 3 PO 4 m) ZnCl 2 n) PbCO 3 19) For the following molecular (covalent) compounds, write the formula or write the name: a) carbon monoxide b) xenon tetrafluoride c) silicon dioxide d) iodine pentachloride e) P 2 O 5 f) P 4 O 10 g) SF 6 h) NI 3 20) Define: a) Precipitate - b) Aqueous solution - 21) Why do chemical equations need to be balanced? 22) List the 5 types of chemical reactions AND state how you would identify their type simply by looking at the equation: Type of reaction: How you would identify their type simply by looking at the equation: S = Synthesis (Combination) 2 or more reactants and only 1 product D = SR = DR = C = 23) Balance the following equations and identify the type of reaction occurring: a) Zn + HCl ---> ZnCl 2 + H 2 b) KClO 3 ---> KCl + O 2 c) S 8 + F 2 ---> SF 6 d) Fe + O 2 ---> Fe 2 O 3 e) C 2 H 6 + O 2 ---> CO 2 + H 2 O f) MgO Mg + O 2 Page 2 12/10/2014

3 24) For each of the following; predict the products, balance and identify the type of reaction occurring. a) Fe + HCl (assume that the iron has a +3 charge as a product) b) Ca(OH) 2 + HCl c) NaI + Br 2 d) Pb(NO 3 ) 2 + CuSO 4 25) Define: a) Avogadro s number - b) Molar mass - c) Empirical formula d) Molecular formula - e) Hydrate - f) Atomic mass unit - Stoichiometry: Show all work for calculations: 26) What is the molar mass of Rb 2 Cr 2 O 7? 27) What is the % by mass of C in Pb(C 2 H 3 O 2 ) 2? 28) What is the molar mass of CoCl 2 6H 2 O? 29) How many grams of iron are in a 150 g sample of an iron/aluminum ore containing 27% aluminum? 30) How many grams of C 6 H 12 O 6 would contain 15 g of carbon? 31) What is the number of molecules in g of H 2 O? 32) How many atoms are in 0.26 mol of CuO? 33) What is the mass of 1.75 x molecules of NH 3? 34) Determine the empirical formula for a compound that was found to contain 71.65% Cl, 24.27% C, and 4.07% H. 35) Caffeine has a molar mass of and has been determined to contain 49.48% C, 5.15% H, 28.87% N, and 16.49% O. What are caffeine s molecular and empirical formulas? Page 3 12/10/2014

4 36) One disadvantage of burning propane (C 3 H 8 ) is that carbon dioxide is one of the products. The released CO 2 increases the growing concentration of CO 2 in the atmosphere. How many moles of carbon dioxide are produced when 10.0 moles of propane are burned in excess oxygen on a gas grill? 37) Water decomposes to produce hydrogen gas and oxygen gas. How many grams of water would be required to produce 10.0 moles of hydrogen gas? 38) For every 25.0 grams of carbon dioxide that are absorbed in photosynthesis, how many moles of glucose (C 6 H 12 O 6 ) could be produced according to the following equation?: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 39) One series of reactions that inflates air bags in automobiles is the decomposition of sodium azide (NaN 3 ). Determine the amount of N 2 produced if g of NaN 3 is decomposed using the following unbalanced equation: NaN 3 Na + N 2 40) Nitrogen gas reacts with hydrogen gas to produce ammonia: If g of nitrogen gas reacts with 20.0 g of hydrogen gas what mass of ammonia will be produced? 41) Use the Haber process (nitrogen gas reacts with hydrogen gas to form ammonia) to answer the following questions: a) What mass of ammonia is formed when 25.0 g of nitrogen reacts? b) What mass of ammonia is formed when 12.0 g of nitrogen is combined with 3.05 grams of hydrogen gas? c) If 25.0 g of nitrogen reacts to form 28.7 g of ammonia, what is the percent yield of the reaction? Solutions & Stoichiometry 42) Fill in the chart: Definition Type of compounds Examples (Strong) Electrolyte Weak electrolyte Nonelectrolyte 43) When an ionic solid dissolves in a solvent (ex: NaCl in H 2 O) the substance dissociates into. Page 4 12/10/2014

5 44) The solution now conducts an electrical current and is termed an. 45) Write the net ionic equations for the following aqueous solutions: a) hydrochloric acid + sodium hydroxide b) zinc chloride + hydrogen sulfide gas c) barium acetate + lithium sulfate d) silver nitrate + potassium bromide 46) A M of ml intravenous (IV) solution contains 5.10 g of a compound. What is the molar mass of this compound? 47) How many grams of sodium hydroxide are required to prepare ml of a 2.00 M solution? 48) How many grams of NaCl are present in 2.25 L of a 1.50 M NaCl solution? 49) What is the concentration of lithium ions in 3.5 M lithium carbonate? 50) How many milliliters of 12 M HCl are needed to make 500. ml of 0.10 M HCl? 51) What is the volume of distilled water that should be added to 10.0 ml of 6.00 M HCl in order to prepare a M solution? 52) If 10.0 g of NaCl is dissolved in 120 ml of solution, what is the concentration of the solution? 53) Describe how to prepare 250. ml of M NaCl (MM= g/mol) 54) What is the oxidation state of sulfur in Na 2 SO 4? Nitrogen in Ca(NO 3 ) 2? 55) Identify what substance is oxidized and what substance is reduced in the following redox reaction. NaF + Br 2 NaBr + F 2 is oxidized from to. is reduced from to. 56) Use the following equation to answer the following questions: Pb(NO 3 ) 2 + KI KNO 3 + PbI 2 a) Write the net ionic equation. b) What is the precipitate? c) Why does the substance from part (b) precipitate? 57) Which ions are ALWAYS soluble? Thermochemistry 58) Write the balance chemical equation for the complete combustion of ethane (C 2 H 6 ). 59) If 30.2 kj of heat is required to vaporize 142 g of substance X, what is the heat of vaporization of substance X? Page 5 12/10/2014

6 60) Given: CH 4 + 2O 2 CO 2 + 2H 2 O ΔH= kj What is the enthalpy change for this reaction? 5CO H 2 O 5CH O 2 61) Given the thermochemical equation N 2 (g) + 3H 2 (g) 2NH 3 (g) ΔH = 91.8 kj, how much energy is given off when g of N 2 reacts? 62) 2C(s) + 2H 2 O(g) CH 4 (g) + CO 2 (g) Determine the standard enthalpy of change for this reaction from the following standard enthalpies of reaction: 1 C(s) + H 2 O(g) CO(g) + H 2 (g) ΔHº = kj 2 CO(g) + H 2 O(g) CO 2 (g) + H 2 (g) ΔHº = kj 3 CH 4 (g) + H 2 O(g) 3H 2 (g) + CO(g) ΔHº = kj 60) Using the enthalpies of formation listed in Appendix C (p. 1112) of your textbook, calculate the enthalpy of reaction for the following equation: C 2 H 5 OH(l) + 3O 2 (g) 2CO 2 (g) + 3H 2 O(l) 63) What is a state function and name 2 examples and 2 nonexamples? 64) Why does it take less energy to raise water s temperature from 92ºC to 97ºC than to raise water s temperature from 97ºC to steam at 10 ºC? 65) What type of reaction is indicated by a negative ΔH? 66) A piece of metal weighing grams is put into boiling bath water. After 10 minutes, the metal is immediately placed in 100.0g of water at 40.0 ºC. The maximum temperature that the system reaches is 47ºC. What is the specific heat of the metal (in cal/g C)? The specific heat of water is 1.00 cal/g o C. 67) What are the first and second laws of thermodynamics? 68) What is the difference between stand enthalpy and standard enthalpy of formation ( H f ). What does standard mean? Kinetics For next question, use N 2 + 3H 2 2NH 3 + heat 69) How does each factor affect the rate of the chemical reaction shown above? Factors that affect reaction rate: The rate of the reaction. (Circle your choice) Concentration of the reactants increases Increases Decreases Concentration of the reactants decreases Increases Decreases Temperature increases Increases Decreases Temperature decreases Increases Decreases An inhibitor is added Increases Decreases A catalyst is added Increases Decreases The pressure of a reactant gas is increased Increases Decreases The pressure of a reactant gas is decreased Increases Decreases Crushing a solid reactant into smaller pieces Increases Decreases 70) How does a catalyst affect chemical reactions and how does a catalyst work? 71) Give an example of a rate law that in which the units of rate are equal to the units of the rate constant. 72) Give an example of a rate law that is third order overall. Page 6 12/10/2014

7 73) Draw and label the following reaction diagrams. Be sure to label the activation energy (E a ) and the change in heat ( H) on each diagram: Exothermic Exothermic with a Catalyst Endothermic 74) Fill in the table below: Overall order Differential rate law Units for k Integrated rate law Straight line graph Zero Rate = k [A] = k Time vs. First Second For the next 3 questions, use laboratory data below Trial [A] [B] [C] Initial Rate (mol/ls) M M M M M M M M M M M M ) Write the Rate Law 76) What is the overall order? 77) Rate Constant = (value and units) 78) How much of a g sample of 198 Au is left after 10.8 days if its half-life is 2.70 days? 79) The mechanism of a reaction is shown below. HOOH + I HOI + OH (slow) HOI + I I 2 + OH (fast) 2OH + 2H 3 O + 4H 2 O (fast) a) What is the overall reaction? b) Which compounds are intermediates? c) Predict the rate law based on this mechanism. d) What is the overall order of the reaction? 80) Sketch a Maxwell-Boltzmann distribution for two different substances, one at a higher temperature and one at a lower temperature. Be sure to label the axes and identify which line corresponds to which temperature. Page 7 12/10/2014

8 Equilibrium 81) Define equilibrium. 82) Write the equilibrium expressions for the Haber process (formation of ammonia). K p = K c = 83) If K p = 23.7 for the reaction in the previous question, what is the partial pressure of NH 3 if the partial pressure of N 2 is 2.00 atm and the partial pressure of H 2 is 3.00 atm? 84) What is the equation that relates K p and K c? What does each variable represent? K p = ; K c = 85) If K c is 1.23 at 300 Kelvin, for the following reaction, what is the K p? 2 A (g) 2 B (g) + 2 C (g) 86) If equilibrium shifts right, how are the concentrations of reactants affected? Products? 87) What occurs when you increase the temperature of an exothermic process? 88) If an equation is reversed, what happens to the value of K? 89) If an equation is doubled, what happens to the value of K? 90) Given: 2 SO 3 (g) 2 SO 2 (g) + O 2 (g) K c = 2.4 x at 25ºC What is the value of K c for this equation? SO 2 (g) + ½O 2 (g) SO 3 (g) 91) For the following system at equilibrium, how can you change the conditions to make it shift to the right? (temp, volume, concentrations, pressure) 2 NOBr (g) 2NO (g) + Br 2 (g) + energy 92) What are the three possible relationships between Q and K and what does each indicate? Q = K Reaction is Reaction will shift Reaction will shift 93) Consider the following reaction: 2 A (g) B (g) + 2 C (g) Kc = 2.5 x 10-3 Given: A = 2.00 moles, B = moles, and C = moles in a 2.00 liter container, calculate Q and determine the direction the reaction will shift. Acid-Base Equilibria including Titration and Buffers 94) What is the conjugate acid of: HCO 3 - ; NH 3 ; SO ) What is the conjugate base of: H 3 PO 4 ; H 2 PO 4 - ; HPO 4 2- ; HSO 4-96) The stronger an acid, the its conjugate base. 97) Name all the conjugate acid/base pairs involved in the dissociation of H 2 SO 3 and indicate their formulas. 98) A solution has an [OH - ]= 2.7 x 10-5 M, what is the ph? ; poh? ; [H + ]? 99) What is the ph of a 0.10 M solution of HCl? Page 8 12/10/2014

9 100) What is the ph of a 0.10 M solution of Ca(OH) 2? 101) Decreasing the ph from 8 to 5 increases the acidity by a factor of. 102) If K w of pure water is 7.0 x at 10 C, what is the ph of pure water at this temperature? 103) What is the [H + ] of a solution with a ph of 3.46? 104) What is the ph of 0.010M HCN (K a = 6.2 x )? 105) What factor(s) must be considered when determining the relative strength of the following? a) binary acids in the same group b) binary acids in the same period c) oxyacids 106) M a x V a x #H/formula = x x 107) What is the molarity of a KOH solution if 50.0 ml is neutralized by 17.3 ml of a M H 2 SO 4 solution? 108) What is the formula for K a? ; K b? 109) Use the following information, which acid/conjugate base combination would be best to make a buffer with a ph of 3.00? K a acetic acid = 1.8 x 10-5 K a1 phosphoric acid = 7.5 x 10-3 K a hydrofluoric acid = 6.8 x 10-4 K a2 phosphoric acid = 6.2 x ) What is the Henderson-Hasselbach equation for ph? For poh? 111) Label the following titration graphs with the correct combination of strong acid, strong base, weak acid, or weak base. Also label the equivalence point and half-way point (if appropriate). type 112) Draw molecular representations of all ions present at the labeled points in this graph for the titration of HCN with NaOH. 113) Determine the percent dissociation of HNO 2 at a ph of 2.50 (K a = 4.50 x 10-4 ). Page 9 12/10/2014

10 114) What is the ph of a solution prepared by mixing 75 ml of a 0.20 M solution of HF with 100 ml of a 0.50 M solution of NaF? The pk a of HF is ) How many moles of a monoprotic acid (HA) with a K a =4.9 x 10-6 must be dissolved in 750 ml of H 2 O to produce a solution with ph = 4.50? 116) The K a for HCN is 6.2 x What mass of solid NaCN must be added to 2.0 L of a 0.25 M HCN solution to give a ph of 6.0? 117) What kind of salt is produced by the combination of : a) A strong acid with a strong base b) A strong acid with a weak base c) A weak acid with a strong base 118) Identify the following salts as acidic, basic, or neutral: CaF 2 ; KBr ; NaHCO 3 119) What is the ph when a 30.0 ml sample of M HNO 2 is titrated with 50.0 ml of a M NaOH solution? (K a HNO 2 = 4.50 x 10-4 ) 120) To choose the correct indicator to be used for a titration, the pk a must be similar at the equivalence point. Solubility 121) How does the value of K sp relate to the solubility of the substance? 122) How does evaporation affect the concentration of a saturated solution? 123) When a K sp expression is written for the dissociation of MgCl 2 in solution and the concentrations of the ions are expressed using the variable x, what is the K sp in terms of x? 124) The molar solubility of AgCl in pure water is 1.3 x 10-5 M. Calculate the value of K sp. 125) Calculate the solubility of CaF 2 in g/l (K sp = 4.0 x 10-8 ) 126) What concentration of lead ions is necessary to initiate precipitation given a solution containing M of chloride ions? (K sp PbCl 2 = 1.6 x 10-5 ) 127) Find the molar solubilities of the following: Which one is lowest? Show work! a. CoS K sp = 5 x b. Zn(OH) 2 K sp = 3.0 x c. Ca 3 (PO 4 ) 2 K sp = 2.0 x Page 10 12/10/2014

2) Isotopes are atoms of the same element, which have the same number of but a different number.

2) Isotopes are atoms of the same element, which have the same number of but a different number. AP Chemistry Semester 1 Exam Review Alternate Atomic Structure 1) Fill in the table: Name Per Isotope Symbol Atomic Mass Mass # Atomic # # of protons # of neutrons # of electrons Hydrogen-1 16 16 18 35.45