Chem 101: Introduction to General Chemistry Quiz #6 100 points possible Due before noon on
Wednesday, October 15, 2014 Submit answers on moodle. Each question is worth five points. 1. What is
the molar mass of an oxygen molecule? A. 16.00 g/mol B. 32.00 g/mol C. 18.02 g/mol D. 6.022 X 1023
2.Complete combustion of a hydrocarbon (a molecule containing only carbon and hydrogen) is a
reaction where oxygen reacts with the compound to yield carbon dioxide and water. Which of the
following is the correct, balanced equation for complete combustion of C2H4? A. C2H4 + O2 → H2O +
CO B. C2H4 + 2O2 → 2H2O+ 2CO2 C. C2H4 + 3O2 → 2H2O + 2CO2 D. C2H4 + O2 → 2H2O + 2CO 3. How
many hydrogen atoms are in 14.8 g of (C2H5)2O? A. 8.32 X 1024 B. 1.20 X 1024 C. 8.32 X 10—24 D. 1.20
X 1023 4. What is the mass of 0.250 mol of Mg(OH)2? A. 14.6 g B. 0.252 g C. 4.28 g D. 233 g 5. What is
the molar mass of calcium hydroxide? A. 41.09 g/mol B. 40.08 g/mol C. 57.09 g/mol D. 74.10 g/mol 6.
What is the coefficient for O2 after you balance the following equation: _ C3H8 + O2 ➔ CO2 + H2O A. 3 B. 4 C. 5 D. 10 7. If iron reacts with oxygen to form iron (II) oxide, which of the following
equations correctly represents this process? A. Fe + O → FeO B. Fe2 + O2 → 2 FeO C. Fe + O2 → FeO D. 2
Fe + O2 → 2 FeO 8. How many mol of Al2O3 are present in 86.5 g of Al2O3? A. 5.11 X 1023 mol B. 8820
mol C. 0.848 mol D. 1.18 mol 9. What is the mass of 1.26 mol of CF4? A. 9.01 g B. 69.8 g C. 14.3 g D. 111
g 10. How many hydrogen atoms are in 2.8 mol of ammonia? A. 5.1 X 1024 B. 1.7 X 1024 C. 8.4 D. 17 11.
How many mol of Ca2+ ions are in 2.8 mol of Ca3N2? A. 2.8 mol Ca2+ B. 8.4 mol Ca2+ C. 5.6 mol Ca2+ D.
0.93 mol Ca2+ 12. If potassium reacts with bromine to form potassium bromide, which of the following
equations correctly represents this process? A. K + Br → KBr B. K2 + Br2 → 2 KBr C. 2 K + Br2 → 2 KBr D.
2 K + Br2 → K2Br2 13. How many chloride ions are in 14 mol of CaCl2? A. 1.7 X 1025 Cl— B. 4.2 X 1024
Cl— C. 28 Cl— D. 8.4 X 1024 Cl— 14. What is the coefficient for chlorine after the following equation is
balanced? I2 + Cl2 ➔ __ ICl5 A. 1 B. 2 C. 3 D. 5 15. Is the following equation balanced? Na3PO4
- AlCl3 → 3 NaCl + AlPO4 A. Yes B. No 16. How many carbon atoms are present in 25.6 g of benzene
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(C6H6)? A. 1.18 X 1024 C atoms B. 0.328 C atoms C. 1.97 C atoms D. 1.97 X 1023 C atoms 17. What is the
mass of 67,500 molecules of O2? A. 1.30 X 1030 g B. 3.59 X 10–18 g C. 2.16 X 106 g D. 2.85 X 1020 g 18.
How many moles of O atoms are there in 0.73 moles of Ca(ClO4)2? A. 2.9 B. 5.8 C. 0.73 D. 0.091 19. If
magnesium reacts with hydrogen to form magnesium hydride, which of the following equations
correctly represents this process? A. Mg + H → MgH B. Mg2 + H2 → 2 MgH C. Mg + H2 → MgH2 D. Mg2
- 2 H2 → 2 MgH2 20. If you have 5.0 X 1024 molecules of water, how many mol of water do you have?
A. 8.3 mol H2O B. 2.8 mol H2O C. 1.5 X 102 mol H2O D. 1.8 X 1047 mol H2O
Chemical Reactions
Question 1. What is the molar mass of an oxygen molecule?
Answer: (B) 32.00 g/mol (Lew 38)
Question 2.Complete combustion of a hydrocarbon (a molecule containing only carbon and
hydrogen) is a reaction where oxygen reacts with the compound to yield carbon dioxide and
water. Which of the following is the correct, balanced equation for complete combustion of
C2H4?
Answer: (B) C2H4 + 2O2 2H2O + 2CO2 (Lew 31)
Question 3. How many hydrogen atoms are in 14.8 g of (C2H5)2O?
Answer: (B) 1.20 X 1024
Question 4. What is the mass of 0.250 mol of Mg(OH)2?
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Answer: (B) 14.6 g
Question 5. What is the molar mass of calcium hydroxide?
Answer: (D) 74.10 g/mol
Question 6. What is the coefficient for O2 after you balance the following equation:
_ C3H8 + O2 ➔ CO2 + _ H2O
Answer: (C) 5
Question 7. If iron reacts with oxygen to form iron (II) oxide, which of the following equations
correctly represents this process?
Answer: (D) 2Fe + O2 2FeO
Question 8. How many mol of Al2O3 are present in 86.5 g of Al2O3?
Answer: (C) 0.848 mol
Question 9. What is the mass of 1.26 mol of CF4?
Answer: (D) 111 g
Question 10. How many hydrogen atoms are in 2.8 mol of ammonia?
Answer: (B) 1.7 X 1024
Question 11. How many mol of Ca2+ ions are in 2.8 mol of Ca3N2?
Answer: (B) 8.4 mol Ca2+
Question 12. If potassium reacts with bromine to form potassium bromide, which of the
following equations correctly represents this process?
Answer: (C) 2 K + Br2 2KBr (Lew 90)
Question 13. How many chloride ions are in 14 mol of CaCl2?
Answer: (A) 1.7 X 1025 Cl—
Question 14. What is the coefficient for chlorine after the following equation is balanced?
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_ I2 + Cl2 ➔ __ ICl5
Answer: (D) 5
Question 15. Is the following equation balanced? Na3PO4 + AlCl3 3 NaCl + AlPO4
Answer: (B) No
Question 16. How many carbon atoms are present in 25.6 g of benzene (C6H6)?
Answer: (A) 1.18 X 1024 C atoms
Question 17. What is the mass of 67,500 molecules of O2?
Answer: (B) 3.59 X 10–18 g (Lew 33)
Question 18. How many moles of O atoms are there in 0.73 moles of Ca(ClO4)2?
Answer: (B) 5.8
Question 19. If magnesium reacts with hydrogen to form magnesium hydride, which of the
following equations correctly represents this process?
Answer: (C)Mg + H2 MgH2
Question 20. If you have 5.0 X 1024 molecules of water, how many mol of water do you have?
Answer: (C) 1.5 X 102 mol H2O
