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3rd quarter final Review UNIT 6 The Mole 1. Avogadro's number of representative particles is equal to one ____. a. b. c. d. e. Gram Mole Kilogram Atom two of the above are true 2. All of the following are equal to Avogadro's number EXCEPT ____. a. b. c. d. the number of atoms of bromine in 1 mol Br2 the number of atoms of gold in 1 mol Au the number of molecules of nitrogen in 1 mol N2 the number of molecules of carbon monoxide in 1 mol CO e. the number of formula units of magnesium chloride in 1 mol MgCl2 3. How many moles of gold atoms are in 2.0 x 1023 atoms of gold? a. b. c. d. e. 6.022 x 1023 1.0 0.50 0.33 2 (6.022 x 1023) 4. How many formula units are in 0.50 mol of sodium chloride? a. b. c. d. e. 6.022 x 1023 3.0 x 1023 1.20 x 1024 3.0 0.50 / 6.022x 1023 5. The mass of a mole of NaCl is the ____ a. b. c. d. atomic mass molecular mass molar mass average mass 6. What is the molar mass of carbon dioxide? a. b. c. d. 28.01 g/mol 40.02 g/mol 44.01 g/mol 76.01 g/mol 7. What is the molar mass of calcium hydroxide? a. b. c. d. 41 g/mol 57 g/mol 58 g/mol 74 g/mol 8. What is the number of moles of argon atoms in 120 g of argon? a. b. c. d. e. 0.50 mol 2.0 mol 3.0 mol 120 x (6.022 x 1023) mol 6.022 x 1023 mol 9. Pencil lead is composed of graphite, which is made of carbon. How many atoms of carbon can be found in 6.0 g of pencil lead? a. 1.0 b. 3.01 x 1023 c. 6.022 x 1023 d. 6 x 12 (6.022 x 1023) 10. The lowest whole-number ratio of the elements in a compound is called the ____. a. b. c. d. empirical formula molecular formula mole ratio lowest common denominator formula 11. Which of the following is NOT an empirical formula? a. b. c. d. e. C2N2H7 C3H9O6 Na2SO4 Sb2S3 at least two of the above 12. Which of the following is NOT true about empirical and molecular formulas? a. The molecular formula of a compound can be the same as its empirical formula. b. The molecular formula of a compound can be some whole-number multiple of its empirical formula. c. Several compounds can have the same empirical formula, but have different molecular formulas. d. The empirical formula of a compound can be triple its molecular formula. e. at least two of the above are not true 13. If the molar mass of a compound is 266.7 g/mol and its empirical formula is B2H5, determine the molecular formula. a. b. c. d. e. 23 10 B4H10 B6H15 B20H50 a. Atoms only contains element b. Molecules any covalent compound or nonmetal only c. formula units any ionic compound or metal and nonmetal combined d. Ions any ions with + or - charge 1. 1 mole CuCO3 = 5 atoms 1. Incorrect 2. If there is 1 formula unit, then it contains 5 atoms 2. 1 mole O2 = 32.00 g O2 1. Correct 2. 1 mole of substance has molar mass 3. 1 mole CH3OH = 6.022 x 1023 atoms 1. Incorrect 2. If there are 6.022 x 1023 molecules, then it is correct a. Difference? a. empirical formula is the simplest ratio of the element in a compound. b. You can’t simplify. c. Molecular formula is the simple whole number multiple of its empirical formula. d. You can simplify. i. If the substance is MF, write its empirical formula. ii. H2O iii. K2SO4 iv. C3H6 v. C6H12O3 a. a color change b. release of a gas c. release of energy in form of heat or light d. all of the above a. b. c. d. (s) = solid, (aq) = gas (g) = gas, (l) = liquid (aq) = aqueous, (l) = lethal all of these a. This is a single replacement reaction. b. The cations of both reactants will switch places. c. A white solid will form from two solutions. d. Two of the above are true 17. (NH4)2Cr2O7 N2 + H2O + Cr2O3 a.2, 4, 1, 2 b.1, 1, 4, 1 c.1, 1, 4, 2 d.2, 2, 4,1 18. C8H18 + O2 CO2 + H2O a.2, 4, 16, 18 b.1, 1, 4,1 c.1, 1, 4, 2 d.2, 25, 16, 18 19. Cu + AgNO3 Ag + Cu(NO3)2 a.2, 4, 1, 2 b.1, 1, 4, 1 c.1, 2, 2, 1 d.2, 2, 4, 1 20. Use the activity series, which of the following is correct? a. b. c. d. Br2 < I2 Na < Mg H2 < Na Li < Cu a. b. c. d. Cu + NaCl Ca + HCl I2 + KBr they all take place a. b. c. d. e. f. g. h. i. j. PbI2 Fe(OH)3 AgCl (NH4)2SO4 PbNO3 AgNO3 Cu(C2H3O2)2 Ca3(PO4)2 NaCl CuCO3 A+BCAC+B 2. Single Replacement 3. A+BAB 4. Synthesis 5. ABA+B 6. Decomposition 7. AB+CDAD+CB 8. Double Replacement 9. AB+O2AO2+B2O 10. Combustion 1. __ a) __ CaCl2 + __ Na3PO4 __ NaCl + __ Ca3(PO4)2 DR a) 3 CaCl2 + 2 Na3PO4 6 NaCl + 1 Ca3(PO4)2 ___ b) __ NaHCO3 __ Na2CO3 + __ H2O + __ CO2 D b) 2 NaHCO3 1 Na2CO3 + 1 H2O + 1 CO2 ___ c) ___ C6H14 + ___ O2 ___ CO2 + ___ H2O C c) 2 C6H14 + 19 O2 12 CO2 + 14 H2O _____ d) _____ Na + _____ Cl2 _____ NaCl S d) 2 Na + 1 Cl2 2 NaCl ___ e) ___ Fe + ___ AgNO3 __ Ag + ___ Fe(NO3)3 SR e) 1 Fe + 3 AgNO3 3 Ag + 1 Fe(NO3)3 ____ f) ___ H2 (g) + __ O2 (g) ___ H2O (l) __S_ f) _2__ H2 (g) + _1_ O2 (g) _2__ H2O (l) ___ g) ____ NH3 (g) ___ H2 (g) + ____ N2 (g) D g) 2 NH3 (g) 3 H2 (g) + 1 N2 (g) __ h) __ H2SO4 (aq) +__ Ba(OH)2 (aq) __ BaSO4 (s) + __H2O (l) _DR_ h) _1_ H2SO4 (aq) +_1_ Ba(OH)2 (aq) _1_ BaSO4 (s) + _2_H2O (l) __ i) __ K (s) + __ H2O (l) __ KOH (aq) + __ H2 (g) _SR_ i) _2_ K (s) + _2_ H2O (l) _2_ KOH (aq) + _1_ H2 (g) __ j) __ CaCO3 (s) __ CaO (s) + __ CO2 (g) _D_ j) _1_ CaCO3 (s) _1_ CaO (s) + _1_ CO2 (g) __ k) __ C12H22O11 (s) +__ O2 (g) __ CO2 (g) + __ H2O (l) _C_ k) _1_ C12H22O11 (s) +_12_ O2 (g) _12_ CO2 (g) + _11_ H2O (l) CHEMISTRY Review for midterm UNIT 8 Stoichiometry 25. In the reaction: 2 Al(OH)3 + 3 Ca(NO3)2 3 Ca(OH)2 + 2 Al(NO3)3. If 6 moles of aluminum nitrate were produced, how many moles of calcium nitrate were consumed? A. 3 moles B. 6 moles C. 9 moles D. 12 moles E. 15 moles 26. If 10 moles of methane combusts in an excess of oxygen, how many moles of water would be produced? A. 2. 5 moles B. 5 moles C. 10 moles D. 20 moles E. 40 moles 27. In the unbalanced equation: __CuSO4 + __K3PO4 __K2SO4 + __Cu3(PO4)2 if 12 moles of copper (II) sulfate reacted with an excess of potassium phosphate, how many moles of potassium sulfate are produced? 27. In the unbalanced equation: 3CuSO4 + 2K3PO4 3K2SO4 + 1Cu3(PO4)2 if 12 moles of copper (II) sulfate reacted with an excess of potassium phosphate, how many moles of potassium sulfate are produced? A. B. C. D. E. 4 moles 8 moles 12 moles 16 moles 24 moles 28. If 4 moles of potassium carbonate reacts with an excess of iron (III) hydroxide, how many moles of potassium hydroxide will be produced? A. 1 mole B. 2 moles C. 4 moles D. 8 moles E. 12 moles 29. Consider the unbalanced equation: _Cu + _AgNO3 _Cu(NO3)2 + _Ag . If 3 moles of silver are produced, how many moles of copper were used? 29. Consider the unbalanced equation: 1Cu + 2AgNO3 1Cu(NO3)2 + 2Ag . If 3 moles of silver are produced, how many moles of copper were used? A. 1 mole B. 1.5 moles C. 2 moles D. 2.5 moles E. 3 moles 30. In a chemical reaction, the amount of product that is calculated and could be formed is called the A. limiting reactant B. excess reactant C. actual yield D.theoretical yield 31. In the following: CH4 + 2O2 CO2 + 2H2O, how many grams of CO2 are formed when 10.0 moles of oxygen reacts with excess methane? A. 220 g B. 110g C. 44 g D.22 g 32. When making cheeseburgers, how many complete cheeseburgers can be made using 101 buns, 50 patties, 75 slices of cheese, and 43 tomato slices? (recipe: 2 buns, 1 patty, 1 slice of cheese, 1 tomato slice) A. B. C. D. 51 50 38 43 33. When making cheeseburgers, which is limiting if there are 101 buns, 40 patties, 70 slices of cheese, and 43 tomato slices? (recipe: 2 buns, 1 patty, 1 slice of cheese, 1 tomato slice) A. Buns B. Patties C. Cheese D. tomato 34. Use the answer from #33. When making cheeseburgers, what is the theoretical yield if there are 101 buns, 40 patties, 70 slices of cheese, and 43 tomato slices? (recipe: 2 buns, 1 patty, 1 slice of cheese, 1 tomato slice) A. B. C. D. 101 40 70 43 35. Use the answer from #33, 34. If you made 30 cheeseburgers, what is the percent yield if there are 101 buns, 40 patties, 70 slices of cheese, and 43 tomato slices? (recipe: 2 buns, 1 patty, 1 slice of cheese, 1 tomato slice) A. B. C. D. 25% 50% 75% 100% 36. In the equation NaCl (aq) + AgNO3 (aq) NaNO3(aq) + AgCl (s) how many moles of NaCl would be required to form 3.3 moles of AgCl? A. 1.0 B. 3.3 C. 6.6 D. 1.7 37. In an experiment, 100 g of bromine react with excess lithium in the reaction: 2Li + Br2 2LiBr. You calculated that you would produce 150 g of sodium chloride, but you only collected 105 g of sodium chloride from the experiment. Which set up represents the calculation for the percent yield of lithium bromide? A. C. B. D. For questions 38-43, use the following information: a student immersed a piece of zinc wire in a solution of silver hydroxide, producing silver crystals and a solution of zinc (II) hydroxide. 1 Zn (s) + 2 AgOH (aq) 2 Ag (s) +1 Zn(OH)2 (aq) (balanced) a student immersed a piece of zinc wire in a solution of silver hydroxide, producing silver crystals and a solution of zinc (II) hydroxide. 1 Zn (s) + 2 AgOH (aq) 2 Ag (s) +1 Zn(OH)2 (aq) 39. If I want to produce 24.6 moles of silver, how many moles of silver hydroxide should I use? Mole to mole 24.6 mol Ag 2 mol AgOH X 2 mol Ag = 24.6 mol AgOH a student immersed a piece of zinc wire in a solution of silver hydroxide, producing silver crystals and a solution of zinc (II) hydroxide. Mass to mass 1 Zn (s) + 2 AgOH (aq) 2 Ag (s) +1 Zn(OH)2 (aq) 40. If I produced 87.7 grams of zinc (II) hydroxide, how many grams of zinc did I react? 87.7 g Zn(OH)2 X 1 mol Zn(OH)2 99.41g X Zn(OH)2 1 mol Zn 1 mol Zn(OH)2 65.38 g Zn x 1 mol Zn = 57.7 g Zn 1 Zn (s) + 2 AgOH (aq) 2 Ag (s) +1 Zn(OH)2 (aq) 2 numbers 2 equations 41. If I reacted 25.6 grams of silver hydroxide with 25.6 grams of zinc, what was my limiting reactant? 1 mol AgOH 25.6 g X X AgOH 124.88 g AgOH 1 mol Zn 2 mol Ag 25.6 X X g Zn 65.38 g Zn 2 mol AgOH 2 mol Ag 1 mol Zn = = 0.205 mol Ag 25.6 g AgOH is limiting 0.783 mol Ag 1 Zn (s) + 2 AgOH (aq) 2 Ag (s) +1 Zn(OH)2 (aq) Theoretical yield Gram to gram 42. If I have 40.5 grams of zinc and an excess of silver hydroxide, what is my theoretical yield of silver? 40.5 g Zn 1 mol Zn X 65.38g X Zn 2 mol Ag 1 mol Zn 107.87 g Ag x 1 mol Ag = 133 g Ag 1 Zn (s) + 2 AgOH (aq) Find theoretical yield 2 Ag (s) +1 Zn(OH)2 (aq) Find percent yield 43. If I have 40.5 grams of zinc and excess silver hydroxide but only produced 5.0 grams of silver crystals, what was my percent yield? 1 mol Zn 40.5 g Zn X 107.87 g Ag 2 mol Ag x 65.38g X Zn 1 mol Zn 1 mol Ag P = Actual / Theoretical x 100 5.0 g 133 g X 100 = 3.8 % = 133 g Ag 44. In the unbalanced equation, __ C12H22O11 +__ O2 __ CO2 + __ H2O, How many grams of water would be formed when 1.0 mole of sucrose reacts with excess oxygen? Mole to mass 44. In the unbalanced equation, 1 C12H22O11 + 12 O2 12 CO2 + 11 H2O, How many grams of water would be formed when 1.0 mole of sucrose reacts with excess oxygen? 1.0 mol X C12H22O11 11 mol H 2O 1 mol C12H22O11 X 18.02 g H 2O 1 mol H2O = 198.22 g H2O