Practice TEST KEY - Chapter 1 PDF

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CHE 103 Practice exam 1 Part I Multiple choies. Circle the right answer. 1. Which of the following does not represent a chemical change A) Iron rusting B) reaction sodium metal with water C) Dissolving sugar in water D) Souring of milk E) Leaves changing color 2. Express the following result to the proper number of significant figures: 45.36 3.2 = ? A) 14 B) 14.18 C) 14.2 D) 14.175 3. If 33.1 g of a metal occupies a volume of 4.55 mL, what is the density of the meta l in g/mL? A) 7.27 B) 0.137 D) 4.54 E) 18.6 4. A solution weights 115 grams and the density is 1.23 g/mL. What is the volume in mL of this solution? A) 0.0107 B) 114. C) 116. D) 93.5 E) 141 5. A reaction contains 5 g of A and 6 g of B. how many grams of C and D should be obtained? 1A + 3B  2C + 4D A) 23 B) 11 C) 1 D) 10 6. An 56Fe2+ particles contains A) 28 protons, 28 neutrons, and 26 electrons B) 28 protons, 30 neutrons, and 24 electrons C) 26 protons, 26 neutrons, and 26 electrons D) 54 protons, 56 neutrons, and 56 electrons 7. Naturally occurring chlorine consists of only two isotopes: chlorine-35 and chlorine-37. The atomic mass for chlorine on the Periodic Table is approximately 35.5. What are reasonable estimates of the relative percentages of chlorine-35 and chlorine-37, respectively? A) 50, 50 B) 25, 75 C) 75, 25 D) 67, 33 8. Which of the following compounds is molecular? A) Fe2O3 B) NaOH C) NF3 D) CuCl2 9. Which name is incorrect? A) MgS magnesium sulfide C) FeCl3 Iron (III) chloride B) HBr hydrogen bromide D) LiO2 dilithium oxide 10. What is the correct formula for Iron (III) oxide? A) Fe3O B) FeO3 C) Fe2O3 D) Fe3O2 11. What is the correct name of Cu(ClO3)2? A) Copper chlorite B) copper (II) chlorite C) copper (II) chlorate D) copper (II) perchlorate 12. Which of the following compound is ionic? A) SF6 B) MgO C) SOCl2 D) HNO3 13. What is the name of the following binary compound? BaCl2 A) Barium chloride C) Barium (II) chloride

B) Barium dichloride D) barium chlorine 14. Which of the following could be an empirical formula? A) C2H6 B) C3H8 C) C2H2Cl2 E) C10H10 15. Which of the following is incorrectly labeled? A) HNO2-strong electrolyte C) KCl- strong electrolyte B) HCl-strong electrolyte D) NH3- weak electrolyte 16. Which of the following is a weak electrolyte in aqueous solution? A) NH4NO3 B) HCOOH C) HNO3 D) NaOH 17. Which of the following is a non-electrolyte in aqueous solution? A) H2SO4 B) KBr C) CH3CH2OH D) HClO2 18. Which of the following is a strong electrolyte in aqueous solution? A) NaCl B) CH4 C) CO D) H2O 19. Which of the following is a spectator ion in the reaction between NaOH and HCl? A) Na+ (B NA is soluable) B) OH- C) K+ D) H+ 20. Which of the following is soluble in water? A) AgCl B) PbSO4 C) FeS D) Mo(NO3)2 21. Which reactions will Not produce a precipitate from aqueous solution? A) Pb(NO3)2 + Na2CO3 B)NaBr + Al2(SO4)3 C) ZnCl2 + (NH4)2S

D) FeSO4 + Ba (OH)2

22. Which is the net ionic equation of the following precipitation reaction? 2AgNO3 (aq) + Na2CrO4 (aq) → Ag2CrO4 (s) + 2NaNO3 (aq) A) 2Ag+ (aq) + 2NO3 - (aq) + CrO4 2- (aq) + 2Na+ (aq) → Ag2CrO4 (s) + 2Na+ (aq) + + 2 NO3 - (aq) B) Ag2 2+ (aq) + 2NO3 - (aq) + CrO4 2- (aq) + 2Na+ (aq) → Ag2CrO4 (s) + 2Na+ (aq) + + 2 NO3 - (aq) C) 2Ag+ (aq) + CrO4 2- (aq) → Ag2CrO4 (s) D) NO3 - (aq) + Na+ (aq) → NaNO3 (aq) 23. The net ionic equation for the reaction between aqueous ammonia and hydrochloric acid is which of the following? A) HCl(aq) + NH3(aq) NH4Cl(aq) B) H+(aq) + OH-(aq)  H2O(l) C) H+(aq) + Cl- + NH3(aq)  NH4+(aq) +ClD) H+(aq) + NH3(aq)  NH4+(aq) 24. What is the oxidation number of chlorine in HClO2? A) -1 B) + 1 C) + 3 D) + 7 25. What is the oxidation number of iron in Fe3O7? A) + 3 B) 4 2/3 C) 5 D) 7 26. In the reaction SiO2(s) + 2C(s)  Si(s) + 2CO(g), which species is the oxidizing agent? A) Si B) C C) SiO2 D) CO 27. Which of the following reactions does NOT involve oxidation-reduction?

A) AgNO3 + NaCl  AgCl (S) + NaNO3 B) Zn + 2HCl  ZnCl2 + H2 C) 2Na + 2H2O  2NaOH + H2 D) MnO2 + 4HCl  Cl2 + 2H2O + MnCl2 28. Consider the following redox reaction: 2MnO4- + 3ClO3- + H2O  3ClO4- + 2MnO2 + 2OHThe reducing agent is A. H2O B. ClO3C. MnO2 D. MnO4 Part II Answer the following questions. Must show work to get full credits. 1. Calculate the mass in grams of 0.333 mol CO2 Solution: 0.333 mol x (44.01 g/mol) = 14.7 g 2. Calculate the number of moles of CO molecules in 125 gram sample of CO. Solution: 125 g x (1 mol/28.01 g) = 4.46 mol 3. How many moles of oxygen atoms are in 2.25 moles of BaSO4?

Solution: 2.25 mol BaSO4 x (4 mol of O/1 mol of H2SO4) = 9.00 mol 4. How many F- ions are in 2.50 moles of BaF2? (NA = 6.02 x 1023)

Solution: 2.50 mol BaF2 x (2 mol of F-/1 mol of BaF2) x 6.02 x 1023 = 3.01 x 1024 5. Calculate the percent of chlorine by mass in PCl3. Solution: Cl% = 3 x 35.45 g/ (30.97 + 3 x 35.45) g = 0.774 =77.4% 6. Calculate the mass in gram of Na+ in 10.0 g of sodium carbonate Solution: 10.0 g Na2CO3 x [(22.99 g x2/ (22.99 x 2 + 12.00 + 48.00)] = 4.34 g 7. The empirical formula of a compound is CH2O. The molar mass of this compound is 360 g/mol. What is the molecular formula? MM of CH2O = 12.00 + 2.016 + 16.00= 30.016 g/mol n = 360/30.016 = 12

Molecular formula = 12 x CH2O = C12H24O12

8. Find the empirical formula of a compound that is 48.38% carbon, 8.12% hydrogen, and 53.5% oxygen by mass. Solution: percent to mass: (.4838) (100 g) = 48.38 g C (.0812 ) (100 g) = 8.12 g H (.5350) (100 g) = 53.38 g O

Mass to mole: (48.38 g C) (1 mol/ 12.10 g C) = 4.028 mol C (8.12 g H) (1 mol/ 1.008 g H) = 8.056 mol H (53.38 g O) (1 mol/ 16.00 g O) = 3.336 mol O Divide by the smallest: (3.336 mol O/ 3.336) = 1 mol O (4.028 mol C/ 3.336) = 1.2 mol C (8.056 mol H/ 3.336) = 2.4 mol H Convert to whole (1 mol O) (5) = 5 mol O (1.2 mol C) (5) = 6 mol C (2.4 mol H) (5) = 12 mol H Answer: C6H12O5...