Name: ________________________ Class: ___________________ Date: __________ ID: A Ch 3 practice test, 3.1-3.6 Multiple Choice Identify the choice that best completes the statement or answers the question. You also need to review mass spec problems. ____ 1. What is the molecular mass of Br2 ? A. 79.90 amu B. 79.90 g C. 159.8 amu D. 159.8 g ____ 2. What is the mass of 4.50 1022 Cu atoms? A. 7.47 10-2 g B. 7.47 10-2 amu C. 4.75 g D. 63.55 amu 3. If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in units of ____ ____ 4. ____ 5. ____ 6. ____ 7. g/mol? A. 2.28 102 g/mol B. 1.71 101 g/mol C. 4.38 10–3 g/mol D. 2.17 102 g/mol Which one of the following does not represent 1.000 mol of the indicated substance? A. 6.022 1023 C atoms B. 26.00 g Fe C. 12.01 g C D. 65.39 g Zn How many C atoms are in 5.50 g of C? A. 5.01 1022 C atoms B. 3.31 1024 C atoms C. 6.02 1023 C atoms D. 2.76 1023 C atoms Determine the number of moles of aluminum in 96.7 g of Al. A. 0.279 mol B. 3.58 mol C. 7.43 mol D. 4.21 mol A gold wire has a diameter of 1.00 mm. What length of this wire contains exactly 1.00 mol of gold? (density of Au = 17.0 g/cm3) A. 2630 m B. 3.69 m C. 251 m D. 14.8 m 1 Name: ________________________ ____ ____ ID: A 8. A silver wire has a diameter of 0.500 mm. What length of this wire contains exactly 1.00 mol of 9. ____ 10. ____ 11. ____ 12. ____ 13. ____ 14. ____ 15. silver? (density of Ag = 10.5 g/cm3) A. 52.3 m B. 222 m C. 13.1 m D. 2.01 m How many moles of CF4 are there in 171 g of CF4? A. 0.51 mol B. 1.94 mol C. 4.07 mol D. 88.0 mol Which of the following CO2 samples contains the greatest number of moles of CO2? A. 3.5 moles CO2 B. 3.21 1023 CO2 molecules C. 4.50 1022 CO2 molecules D. 5.60 g CO2 Calculate the molecular mass of menthol, C10H20O. A. 156.26 amu B. 140.26 amu C. 29.02 amu D. 48.17 amu How many moles of O are in 2.45 moles of H2CO3? A. 2.45 moles O B. 39.2 moles O C. 118 moles O D. 7.35 moles O How many O atoms are there in 51.4 g Calcium sulfate? A. 4.00 B. 2.40 1024 C. 1.13 D. 9.09 1023 Calculate the mass of N in 2.34 g of N2H4? A. 4.68 g N B. 65.6 g N C. 28.02 g N D. 2.05 g N How many grams of nitrogen are there in 7.5 g of Calcium nitrate? A. 0.64 g B. 1.3 g C. 0.15 g D. 1.2 g 2 Name: ________________________ ID: A ____ 16. The mineral hausmannite is a compound of 55Mn and 16O. If 72% of the mass of hausmannite is due to manganese, what is the empirical formula of hausmannite? A. MnO B. Mn3O C. Mn3O4 D. Mn4O3 ____ 17. A compound with an empirical formula of C2H4Br has a molar mass of 215.90 g/mol. What is the molecular formula? A. C4H8Br2 B. C2H4Br C. CHBr D. C6H12Br3 ____ 18. An unknown compound with a molar mass of 223.94 g/mol consists of 32.18% C, 4.50% H, and 63.32% Cl. Find the molecular formula for the compound. A. CHCl B. C6H10Cl4 C. C3H5Cl2 D. C9H15Cl6 ____ 19. A compound was discovered whose composition by mass is 85.6% C and 14.4% H. Which of the following could be the molecular formula of this compound? A. CH4 B. C2H4 C. C3H4 D. C2H6 ____ 20. The molecular weight of the acetic acid (CH3CO2H), rounded to the nearest integer, is ____ amu. A. 60 B. 48 C. 44 D. 32 ____ 21. The mass % of C in methane (CH4) is ____. A. 25.13 B. 133.6 C. 74.87 D. 92.26 E. 7.743 ____ 22. Calculate the percentage by mass of lead in Pb(NO3)2. A. 38.6 B. 44.5 C. 62.6 D. 65.3 E. 71.2 3 Name: ________________________ ID: A ____ 23. Calculate the percentage by mass of hydrogen in PtCl 2(NH3)2. A. 1.558 B. 1.008 C. 0.672 D. 0.034 E. 2.016 ____ 24. One million argon atoms is ____ mol (rounded to two significant figures) of argon atoms. A. 3.0 B. 1.7 10–18 C. 6.0 1023 D. 1.0 10–6 E. 1.0 106 ____ 25. How many molecules of CH4 are in 48.2 g of this compound? A. 5.00 1024 B. 3.00 C. 2.90 1025 D. 1.81 1024 E. 4.00 ____ 26. A sample of CH2F2 with a mass of 19 g contains ____ atoms of F. A. 2.2 1023 B. 38 C. 3.3 1024 D. 4.4 1023 E. 9.5 ____ 27. A sample of CH4O with a mass of 32.0 g contains ____ molecules of CH 4O. A. 5.32 10–23 B. 1.00 C. 1.88 1022 D. 6.02 1023 E. 32.0 ____ 28. The total number of atoms in 0.111 mol of Fe(CO)3(PH3)2 is ____. A. 15.0 B. 1.00 1024 C. 4.46 1021 D. 1.67 E. 2.76 10–24 ____ 29. How many sulfur dioxide molecules are there in 1.80 mol of sulfur dioxide? A. 1.08 1023 B. 6.02 1024 C. 1.80 1024 D. 1.08 1024 E. 6.02 1023 4 Name: ________________________ ID: A ____ 30. How many carbon atoms are there in 52.06 g of carbon dioxide? A. 5.206 1024 B. 3.134 1025 C. 7.122 1023 D. 8.648 10–23 E. 1.424 1024 ____ 31. The molecular formula of aspartame, the generic name of NutraSweet®, is C14H18N2O5. The molar mass of aspartame, rounded to the nearest integer, is ____ g. A. 24 B. 156 C. 294 D. 43 E. 39 ____ 32. There are ____ oxygen atoms in 30 molecules of C 20H42S3O2. A. 6.0 1023 B. 1.8 1025 C. 3.6 1025 D. 1.2 1024 E. 60 ____ 33. A nitrogen oxide is 63.65% by mass nitrogen. The molecular formula could be ____. A. NO B. NO2 C. N2O D. N2O4 E. either NO2 or N2O4 ____ 34. Which hydrocarbon pair below has identical mass percentage of C? A. C3H4 and C3H6 B. C2H4 and C3H4 C. C2H4 and C4H2 D. C2H4 and C3H6 E. none of the above ____ 35. The formula weight of zinc perchlorate is ________ amu. A. 164.7 B. 128.0 C. 79.0 D. 264.1 E. 116.7 ____ 36. How many grams of oxygen are in 56 g of C 2H2O2? A. 11 B. 19 C. 26 D. 31 E. 49 5 Name: ________________________ ID: A ____ 37. How many moles of lithium phosphate (Li3PO4) are contained in 66.6 g of lithium phosphate? A. 0.575 B. 7710 C. 1.11 10–22 D. 4.01 1025 E. 116 ____ 38. What is the empirical formula of a compound that is 66.6% C, 11.2% H, and 22.2% O by mass? A. C4HO B. C6HO2 C. C8H16O2 D. C6H11O E. C4H8O Short Answer 1. A 0.600 g sample of a compound of arsenic and oxygen was found to contain 0.454 g of arsenic. What is the empirical formula of the compound? 2. What percent by mass of oxygen is present in carbon monoxide, CO? 6 ID: A Ch 3 practice test, 3.1-3.6 Answer Section MULTIPLE CHOICE 1. ANS: OBJ: 2. ANS: OBJ: 3. ANS: OBJ: 4. ANS: OBJ: 5. ANS: OBJ: 6. ANS: OBJ: 7. ANS: OBJ: 8. ANS: OBJ: 9. ANS: OBJ: 10. ANS: OBJ: 11. ANS: OBJ: 12. ANS: OBJ: 13. ANS: OBJ: 14. ANS: OBJ: 15. ANS: OBJ: 16. ANS: OBJ: 17. ANS: OBJ: 18. ANS: OBJ: 19. ANS: OBJ: 20. ANS: OBJ: 21. ANS: OBJ: C EK.1.A.3 C EK.1.A.3 A EK.1.A.3 B EK.1.A.3 D EK.1.A.3 B EK.1.A.3 D EK.1.A.3 A EK.1.A.3 B EK.1.A.3 A EK.1.A.3 A EK.1.A.3 D EK.1.A.3 D EK.1.A.3 D EK.1.A.3 B EK.1.A.3 C EK.1.A.1 A EK.1.A.1 B EK.1.A.1 B EK.1.A.1 A 3.3; G4 C 3.3; G4 PTS: 1 DIF: Medium REF: Section: 3.2 PTS: 1 DIF: Medium REF: Section: 3.2 PTS: 1 DIF: Easy REF: Section: 3.2 PTS: 1 DIF: Medium REF: Section: 3.2 PTS: 1 DIF: Medium REF: Section: 3.2 PTS: 1 DIF: Medium REF: Section: 3.2 PTS: 1 DIF: Difficult REF: Section: 3.2 PTS: 1 DIF: Difficult REF: Section: 3.2 PTS: 1 DIF: Easy REF: Section: 3.3 PTS: 1 DIF: Medium REF: Section: 3.3 PTS: 1 DIF: Easy REF: Section: 3.3 PTS: 1 DIF: Medium REF: Section: 3.3 PTS: 1 DIF: Medium REF: Section: 3.3 PTS: 1 DIF: Medium REF: Section: 3.3 PTS: 1 DIF: Medium REF: Section: 3.3 PTS: 1 DIF: Difficult REF: Section: 3.6 PTS: 1 DIF: Medium REF: Section: 3.6 PTS: 1 DIF: Medium REF: Section: 3.6 PTS: 1 DIF: Medium REF: Section: 3.6 PTS: 1 DIF: 2 REF: Page Ref: 3.3 PTS: 1 DIF: 2 REF: Page Ref: 3.3 1 ID: A 22. ANS: OBJ: 23. ANS: OBJ: 24. ANS: OBJ: 25. ANS: OBJ: 26. ANS: OBJ: 27. ANS: OBJ: 28. ANS: OBJ: 29. ANS: OBJ: 30. ANS: OBJ: 31. ANS: OBJ: 32. ANS: OBJ: 33. ANS: OBJ: 34. ANS: OBJ: 35. ANS: OBJ: 36. ANS: OBJ: 37. ANS: OBJ: 38. ANS: OBJ: C 3.3; G4 E 3.3; G4 B 3.4; G4 D 3.4; G4 D 3.4; G4 D 3.4; G4 B 3.4; G4 D 3.4; G4 C 3.4; G4 C 3.4; G7 E 3.4; G4 C 3.5; G2 D 3.5; G2 D 3.3; G4 D 3.4; G4 A 3.4; G4 E 3.5; G4 PTS: 1 DIF: 2 REF: Page Ref: 3.3 PTS: 1 DIF: 3 REF: Page Ref: 3.3 PTS: 1 DIF: 2 REF: Page Ref: 3.4 PTS: 1 DIF: 3 REF: Page Ref: 3.4 PTS: 1 DIF: 3 REF: Page Ref: 3.4 PTS: 1 DIF: 2 REF: Page Ref: 3.4 PTS: 1 DIF: 3 REF: Page Ref: 3.4 PTS: 1 DIF: 2 REF: Page Ref: 3.4 PTS: 1 DIF: 3 REF: Page Ref: 3.4 PTS: 1 DIF: 1 REF: Page Ref: 3.4 PTS: 1 DIF: 2 REF: Page Ref: 3.4 PTS: 1 DIF: 3 REF: Page Ref: 3.5 PTS: 1 DIF: 3 REF: Page Ref: 3.5 PTS: 1 DIF: 2 REF: Page Ref: 3.3 PTS: 1 DIF: 3 REF: Page Ref: 3.4 PTS: 1 DIF: 3 REF: Page Ref: 3.4 PTS: 1 DIF: 4 REF: Page Ref: 3.5 DIF: Medium REF: Section: 3.6 OBJ: EK.1.A.1 DIF: Medium REF: Section: 3.5 OBJ: EK.1.A.1 SHORT ANSWER 1. ANS: As2O3 PTS: 1 2. ANS: 57% PTS: 1 2