CHEM099 Final Exam Review with Solutions

CHEM099 Final Exam Review Expected Outcomes 1. Use dimensional analysis to perform calculations and express results of calculations with correct units and number of significant figures. 2. Identify the various states of matter and describe the common physical properties of each state. 3. Identify and distinguish physical and chemical properties and changes. 4. Describe the major components of the atom and write symbols for atoms, ions, and isotopes. 5. Determine nomenclature and formulas for ionic and covalent compounds. 6. Convert moles, masse s, and numbers of particles. 7. Determine percent composition and understand and apply mole concept to determine empirical and molecular formulas. 8. Balance chemical equations, classify reaction types, and determine products of reactions. 9. Use stoichiometry and balanced equations to determine amounts and masses of substances used up and produced in reactions as well as percent yields. 10. Determine solution concentrations and calculate the amounts of material s involved in solution reactions. 11. Analyze and solve problems that include a combination of concept s from various chapters. Review Questions 1. Which of the following is a chemical change? (A) methane gas is burned (C) water is vaporized (B) paper is shredded (D) salt is dissolved in water 2. How many significant figures are in the measurement, 0.0005890 g? (A) 3 3. 850 nm is equal to: (A) 8.5 x 109 m (B) 4 (C) 5 (D) 7 (B) 8.5 x 10─9 m (C) 8.5 x 10─7 m (D) 8.5 x 10─10 m 4. What answer should be reported, with the correct number of significant figures, for the following calculation? (433.621 ─ 333.9) x 11.90 = (A) 1.19 x 103 (B) 1.187 x 103 (C) 1.1868 x 103 (D) 1.18680 x 103 5. A temperature of ─31.0 °C is equivalent to (A) ─304.2 K (B) 304.24 K (C) 242.2 K (D) 329.2 K 6. A piece of metal ore weighs 8.25 g. When placed into a graduated cylinder containing water, the liquid level rises from 21.25 mL to 26.47 mL. What is the density of the ore? (A) 0.312 g/m L (B) 0.633 g/mL (C) 1.58 g/mL (D) 3.21 g/mL 7. The density of mercury is 13.6 g/mL, calculate the volume of a 20 .0 g sample of mercury. (A) 0.680 mL (B) 6.40 mL (C) 272 mL (D) 1 .47 mL 8. A substance with a melting point of ─218 °C and a boiling point of ─182 °C is a __________ at 20 °C. (A) Gas (B) Liquid (C) Solid 1 (D) not enough info given 9. Which of these elements is an alkaline earth metal ? A) Na (B) Ca (C) Cu 10. Which of these elements is halogen ? A) I (B) K (D) Br (C) Kr (D)Ba (C) C (D) Sn 11. Which of the following elements is a metalloid? (A)Al (B) Ge 12. Which of these elements exists as diatomic molecules under ordinary conditions? (A) C (B) P (C) He 13. Which of the following statements is NOT true? (D) N (B) The electron has a charge of ─1. (D) The neutron has no electrical charge. (A) The neutron has a charge of + 1. (C) The proton has a relative mass of ∼1 amu. 14. Atom X has 6 proton s and 6 neutrons, atom Z has 6 protons and 7 neutrons. These atoms are: (A) Isotopes (B) Isomers (C) Isobars (D) None of these 15. An atom containing 19 protons, 20 neutrons, and 19 electrons has a mass number of (A) 58 (B) 39 (C) 20 (D) 19 16. Calculate the atomic mass of silver if silver has 2 naturally occurring isotopes with the following masses and natural abundances: Ag- 107 (106.90509 amu, 51.84%) Ag-109 (108.90476 amu, 48.46%) (A) 107.90 amu (B) l 08.00 amu (C) 107.79 amu (D) 108.19 amu 17. What species is represented by the following information? p+ = 12 (A) Si4+ e─ = 10 n = 14 (B) Mg2+ (C) Si2+ (D) Mg 18. Calculate the mass percent compos ition of lithium in Li3PO4. (A) 26.75 % (B) 17.98 % 19. Which of the following compounds is ionic? A) PH3 (B) CCl4 (C) 30.72 % (D) 55.27 % (C) NaCN (D) NO2 20. One mole of hydrogen gas contains... (A) 1 g of H (B) 1 atom of H (C) 6.02 x 1023 atoms of H (D) 1.20 x 1024 atoms of H 21. The molar mass of (NH4)2SO4 is (A) 70 g/mol 22. 80.16 g of Ca contains (A) 6.02 x1023 (B) 92 g/mol (C) 1 14 g/mol (D)132 g/mol atoms of Ca. (B) 1.500 x l 023 (C) 1.204 x 1024 (D) 2.400 x 1024 23. How many moles of Cu are contained in 2.54 g Cu? (A) 0.0847 (B) 25.0 (C) 161 (D) 0.0400 24. How many grams of Ag are contained in 4 .52 moles of AgNO3? (A) 488 g (B) 37.6 g (C) 23.9 g 2 (D) 768 g #25 and #26 refers to the following chemical eq uation. 2C4H10 (g) + 13O2 (g) → 8CO2 (g) + 10 H2O (l) 25. How many moles of H2O are produced when 5.0 moles of C4H10 react? (A) 5.0 (B) 10 (C) 25 (D) 50 26. How many molecules of CO2 are produced from 5.0 moles of C4H10? (B) 1.20 x 1025 (A) 8 (D) 4.82 x 1024 (C) 80 27. What is the type of the following reaction? SO3(g) + H2 O(l) → H2 SO4(aq) (A) synthesis reaction (C) single replacement reaction (B) decomposition reaction (D) double replacement reaction 28. What is the volume of a 20.0 mL solution in cubic millimeter (mm3 )? (A) 20 mm3 (B) 0.020 mm3 (C) 20000 mm3 (D) 0.00002 mm3 29. How many moles of oxygen atoms are in 2 moles of Ca(NO3)2? (A) 6 moles (B) 12 moles (C) 3 moles (D) 2 moles 30. A nonmetal element, X, combines with Mg to form an ionic compound with formula Mg3 X2 . What would be the ionic formula formed between Al and X? (B) Al3X3 (A) Al3X2 (C) Al2X3 (D) AlX 31. Which of the following is NOT a mixture? (A)salt water (B) tea (C) air (D) ice 32. Chlorine has two stable isotopes, Cl─35 and Cl─37. If their exact masses are 34.9689 amu and 36.9695 amu, respectively, what is the natural abundance of Cl─35? (The atomic mass of chlorine is 35.45 amu.) (A) 75.95% (B) 24.05% (C) 50.00% (D) 35.00% (E) 37.00% 33. What is the volume of a cube with dimensions 11.0 cm × 11.0 cm × 11.0 cm in m3? (A) 1.331 × 10─3 (D) 1.3 × 103 (C) 1.33 × 10─3 (B) 1.33 × 103 34. Convert 25.0 mi/hr to cm/sec. (1 mi = 1.61 km) 35. Com plete the following table. Use the symbol format given in the first row. Symbol 90 Mo+6 # Protons # Neutrons 54 36. Balance the following equations. a) b) C6H14 + O2 → CO2 + H 2O KClO3 + ____ HCl → ____ KCl + _____ Cl2 + ___ H2O 3 # Electrons Mass Number 55 133 37. Complete the following chemical equations by predicting the products. a) Na + FeBr3 → (B) NaOH + H2SO4(aq) → c) C2H4O2 + O2 → (D) PbSO4 + AgNO3 → e) PBr3 → f) HBr + Al → 38. Complete the following table by providing chemical formula for given names and vice versa. Chemical Name zinc hydroxide Chemical Formula NiS boric acid Mg(CN)2 potassium fluoride B2O3 gold (III) nitrate H3PO4(aq) tetraphosphorus hexasulfide CuCO3 iodic acid 39. Consider the reaction represented by the following unbalanced equation Fe2O3 a) b) c) d) + CO → Fe + CO2 If 27.5 g of Fe2O3 is reacted with 18.6 g of CO, what is the theoretical yield of Fe in grams? If the reaction produced 14.8 g of Fe, what was its percent yield? What is the limiting reactant? How many grams of the excess reactant is left over at the end of the reaction? 40. An organic compound contains carbon, hydrogen and oxygen and has a molar mass of ~306 g/mole. If it contains 47.01% of carbon and 5.99% hydrogen, what is its empirical AND molecular formula? 41. Consider the reaction between hydrochloric acid and zinc to produce zinc chloride and hydrogen gas. a) How many grams of zinc is needed to completely react with 25 mL of 4.0 M hydrochloric acid? b) How many mL of 0.35 M hydrochloric acid is needed to produce 0.234 kg of hydrogen gas? 42. An unknown element, X, has a molar mass of 112.45 g/mole and a density of 2.34 g/mL. a) If an 123 mL solution is 0.45 M in element X, how many actual number of X atoms does it contain? b) How many moles of element X is in a 6.70 L sample of element X? 4 ANSWERS 1. (A) 2. (B) 3. (C) 4. (A) 5. (C) 6. (C) 7. (D) 8. (A) 9. (B) 10. (A) 11. (B) 12. (D) 13. (A) 14. (A) 15. (B) 16. (D) 17. (B) 18. (B) 19. (C) 20. (D) 21. (D) 22. (C) 23. (D) 24. (A) 25. (C) 26. (B) 27. (A) 28. (C) 29. (B) 30. (D) 31. (D) 32. (A) 33. (C) 34. 25.0 𝑚𝑚𝑚𝑚 ℎ𝑟𝑟 × 1.61 𝑘𝑘𝑘𝑘 𝑚𝑚𝑚𝑚 × 103 𝑚𝑚 × 1 𝑘𝑘𝑘𝑘 102 𝑐𝑐𝑐𝑐 1 𝑚𝑚 × 1 ℎ𝑟𝑟 60 𝑚𝑚𝑚𝑚𝑚𝑚 × 1 𝑚𝑚𝑚𝑚𝑚𝑚 60 𝑠𝑠𝑠𝑠𝑠𝑠 = 1.12 𝑥𝑥 103 𝑐𝑐𝑐𝑐/𝑠𝑠𝑠𝑠𝑠𝑠 35. Symbol 90 Mo+6 133 Xe─ # Protons 42 54 # Neutrons 48 79 # Electrons 36 55 Mass Number 90 133 36. (a) 2 C6H14 + 19 O2 → 12 CO2 + 14 H2O b) KClO3 + _6 HCl → ____ KCl + _3_ Cl2 + _3_ H2O 37. (a) Na + FeBr3 → NaBr + Fe (b) NaOH + H2SO4(aq) → Na2SO4 + H2O (c) C2H4O2 + O2 → CO2 + H2O (d) PbSO4 + AgNO3 → Pb(NO3)2 + Ag2SO4 (e) PBr3 → P + Br2 (f) HBr + Al → AlBr3 + H2 38. Chemical Name Chemical Formula zinc hydroxide Zn(OH)2 NiS nickel (II) sulfide boric acid H3BO3(aq) Mg(CN)2 magnesium cyanide potassium fluoride KF B2O3 diboron trioxide gold (III) nitrate Au(NO3)3 H3PO4(aq) phosphoric acid tetraphosphorus hexasulfide P4S6 CuCO3 copper (II) carbonate iodic acid 39. a) Balanced Reaction: Fe2O3 + 3CO → 2Fe + 3CO2 27.5 g Fe2O3 × 18.6g CO × b) HlO3(aq) 14.8 g Fe 19.23g Fe 1 mole Fe2O3 159.7g Fe2O3 1 mole CO 28.011g CO × × 2 mole Fe 1 mole Fe2O3 2 mole Fe 3 mole CO × × 55.85 g Fe 1 mole Fe 55.85 g Fe 1 mole Fe = 19.2345 g Fe = 19.2 g Fe = 24.724 g Fe × 100 = 76.96 % = 77.0% 5 c) Fe2O3 d) 27.5 g Fe2O3 × 1 mole Fe2O3 159.7g Fe2O3 3 mole CO × 1 mole Fe2O3 × 28.011 g CO 1 mole CO = 14.470 g CO used 18.6 g CO – 14.470 g CO = 4.13 g CO = 4.19 g CO left 40. % O = 100% ─ 47.01% – 5.99% = 47.00% oxygen 1 mole C 47.01 g C × 5.99 g H × 12.011 g C 1 mole H = 5.94 mole H = 1.0079 g H 47.00 g O × = 3.91 mole C = 1 mole O 16.00 g O 3.91 mole C 5.94 mole C 2.94 2.94 mole O = 2.94 mole O = ≈ 1.33 × 3 = 4 C 2.94 2.94 Empirical formula: C4H6O3 ≈ 2.0 × 3 = 6 H ≈ 1.0 × 3 = 3 O C4H6O3: 102.09 g/mole n= 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 306 g/mole = 102.09 g/mole ≅3 Molecular formula = C4H6O3 × 3 = C12H18O9 41. Balanced Reaction: 2 HCl (aq) + Zn → ZnCl2 + H2 1L a) (25 mL × 1000 ) (4.0 M) = 0.10 mole HCl mL 1 mole Zn 0.10 mole HCl × 1000g b) 0.234 kg H2 x 232.17 mole HCl x 663.3 L × 1 kg 2 mole HCl × × 1 mole H2 2.0158 g H2 65.39 g Zn 1mole Zn × = 3.2695 g Zn = 3.3 g Zn 2 mole HCl 1 mole H2 = 232.17 mole HCl = 0.35 M 1000 mL 1L x = 663.3 L = 663300 mL = 660000 mL 42. (A) 0.123 L (0.45 M) = 0.123 L × 0.45 mole/L = 0.05535 mole X 0.05535 mole X × c) 6.70 L × 1000 mL 1L × 6.02 x 1023 atom X 1 mole X 2.34 g 1 mL ×× = 3.33 × 1022 atom X = 3.3 × 1022 atom X 1 mole 112.45 g = 139.42 mole = 139 mole X 6