Ch7 Complete Test Bank Chemical Reactions How We Keep Track

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Chapter: Chapter 7

Multiple Choice, Essay, Fill-In-The-Blank

1. Identify the products in the following reaction. What is the state of the S₈ in this reaction?

H₂S (g) + CO (g) → CH₃CO­₂H (aq) + S₈ (s)

chaptername: 7

questiontype: Essay

section: 7.1

Feedback: The answer should include the following information: The products are CH₃CO­₂H (aq) and S₈ (s). The S₈ is a solid.

2. True or False: The state must always be written in a chemical equation in order for the equation to be considered complete.

A) True

B) False

chaptername: 7

questiontype: Multiple Choice

section: 7.1

3. Identify the reactants in the following reaction. Which substances are in the aqueous state?

Fe(NO₃)₃ (aq) + (NH₄)₃PO₄ (aq) → FePO₄ (s) + 3NH₄NO₃ (aq)

chaptername: 7

questiontype: Essay

section: 7.1

Feedback: The answer should include the following information:

Fe(NO₃)₃ (aq) and (NH₄)₃PO₄ (aq) are the reactants.

Fe(NO₃)₃ (aq), (NH₄)₃PO₄ (aq), and 3NH₄NO₃ (aq) are in the aqueous state.

4. How many nitrogen atoms are involved in the following reaction? Has the law of conservation of mass been observed in this reaction?

Fe(NO₃)₃ (aq) + (NH₄)₃PO₄ (aq) → FePO₄ (s) + 3NH₄NO₃ (aq)

chaptername: 7

questiontype: Essay

section: 7.1

Feedback: The answer should include the following information: There are 6 nitrogen atoms involved in this reaction. Yes, the law of conservation of mass has been observed since there are 6 nitrogen atoms on the reactant side and 6 on the product side.

5. True or False: The law of conservation of mass dictates that there must be the same number of reactant molecules as product molecules.

A) True

B) False

chaptername: 7

questiontype: Multiple Choice

section: 7.1

6. How many atoms are there in one molecule of the fatty acid, arachidonic acid, C₂₀H₃₂O₂?

A) 32

B) 20

C) 162

D) 54

chaptername: 7

questiontype: Multiple Choice

section: 7.1

7. True or False: The phases on each side of a chemical equation must be the same in order to obey the law of conservation of mass.

A) True

B) False

chaptername: 7

questiontype: Multiple Choice

section: 7.1

8. The chemical equation shown here is balanced except for the value of x. The value of x is _____.

Ca(ClO₃)₂ → CaCl₂ + xO₂

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.1

9. The chemical equation shown here is balanced except for the value of y. The value of y is ­­­­_____.

H₃PO₄ + yHCl → PCl­₅ + 4H₂O

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.1

10. The chemical equation shown here is balanced except for the value of z. The value of z is _____.

BaCO₃ + zHNO₃ → Ba(NO₃)₂ + H₂CO₃

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.1

11. Balance the following equation and choose the answer that represents the sum of the coefficients in the balanced equation: Sn­­O­₂ + H₂ → Sn + H₂O

A) 4

B) 5

C) 6

D) 8

E) 10

chaptername: 7

questiontype: Multiple Choice

section: 7.1

12. Balance the following equation and choose the answer that represents the sum of the coefficients in the balanced equation: NH₃ +O₂ → NO + H₂O

A) 2

B) 3

C) 4

D) 20

E) 19

chaptername: 7

questiontype: Multiple Choice

section: 7.1

13. Use coefficients to balance this equation:

NaIO₃ + NaHSO₃ → NaHSO₄ + Na₂SO₄ + H₂O + I₂

chaptername: 7

questiontype: Essay

section: 7.1

Feedback: The answer should include the following information:

2NaIO₃ + 5NaHSO₃ → 3NaHSO₄ + 2Na₂SO₄ + H₂O + I₂

14. Which coefficient is incorrect in this equation? What should be coefficient be in order to balance the equation? What is the state of the product?

2Al (s) + 3O₂ (g) → 2Al₂O₃ (s)

chaptername: 7

questiontype: Essay

section: 7.1

Feedback: The answer should include the following information: The coefficient in front of the Al is incorrect. It should be a “4”. The product is a solid.

15. Is the following equation balanced? How can the coefficients be changed to balance it?

2Al + 4HCl → 2AlCl₃ + 3H₂

chaptername: 7

questiontype: Essay

section: 7.1

Feedback: The answer should include the following information: The 4 in front of the HCl should be a 6.

16. According to the following balanced reaction, how many units of octane, C₈H₁₈, will be formed if you start with 16.0 units of carbon monoxide, CO?

8CO (g) + 17H₂ (g) → C₈H₁₈ (l) + 8H₂O (l)

A) 2

B) 6

C) 3

D) 10

chaptername: 7

questiontype: Multiple Choice

section: 7.2

17. Why is the mole used to represent numbers of reactants and products in a chemical reaction instead of the number of atoms and molecules?

chaptername: 7

questiontype: Essay

section: 7.2

Feedback: The answer should include the following information: Atoms and molecules are so small that you would have to use very large numbers to represent how many atoms and molecules are involved in a chemical reaction. The mole is a much more convenient way to express quantities in chemical equations.

18. The mass of one mole of calcium is _____.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

19. The mass of one mole of phosphorus is _____.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

20. The mass of one third of a mole of carbon is _____.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

21. The mass of 4.0 moles of He is _____.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

22. If a sample of NaCl contains 6.0 moles of NaCl, then the sample contains ____ NaCl molecules.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

23. One mole of C₆H₁₂O₆ contains _____ moles of atoms.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

24. 3.0 moles of NH₃ contains _____moles of atoms.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

25. 5.0 moles of CH₄ contains _____ total atoms.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

26. The formula for ammonia is NH₃. If you have 8.0 moles of ammonia, then there are _____ moles of hydrogen atoms.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

27. If your car burns 8.0 kg of octane, C₈H₁₈, per month, then it burns _____ moles of octane.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

28. The molar mass of the following molecule is _____.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

29. The molar mass of caffeine, C₈H₁₀N₄O₂, is _____.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

30. The formula for methane is CH₄. 3.0 × 10²⁶ molecules of methane would weigh _____ in grams.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

31. The molar mass for ozone, O₃, is _____; therefore, _____ grams would be contained in 85.0 moles of ozone.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

32. Determine the number of each type of atom in nicotine. What is the molar mass of this molecule?

chaptername: 7

questiontype: Essay

section: 7.2

Feedback: The answer should include the following information: There are 10 C atoms, 2 N atoms, and 14 hydrogen atoms. Molar mass is 162.23 g/mol.

33. The active ingredient in Mucinex is guaifenesin. The molecular formula for this molecule is C₁₀H₁₄O₄. The molar mass of this molecule is _____.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.2

34. Consider the following balanced chemical equation:

B₂Br₆ + 6HNO₃ → 2B(NO₃)₃ + 6HBr.

To produce 4.5 moles of B(NO₃)₃ _____ moles of HNO₃ are required.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.3

35. Consider the following balanced chemical equation:

Fe₂O₃ + 3CO → 2Fe + 3CO₂

To produce 5.0 moles of CO₂, _____ moles of Fe₂O₃ are required.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.3

36. Consider the following balanced chemical equation:

PCl₃ + 3H₂O → H₃PO₃ + 3HCl

If 4.4 moles of PCl₃ react, _____ moles of HCl are formed.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.3

37. Consider the following balanced chemical equation:

PCl₃ + 3H₂O → H₃PO₃ + 3HCl

If 4.4 moles of PCl₃ react, _____ grams of HCl are formed.

chaptername: 7

questiontype: Fill-In-The-Blank

section: 7.3

38. Chlorofluorocarbons are present

A) as a natural component of the atmosphere.

B) in aerosol sprays, freezers and refrigerators.

C) as a by-product of the formation of acids in the atmosphere.

D) in sewage effluent that ends up in our rivers and the ocean.

chaptername: 7

questiontype: Multiple Choice

section: 7.3

39. The ozone hole

A) can lead to increases in skin cancer rates.

B) has the potential to damage to crops.

C) has formed both in the Arctic and Antarctic.

D) All of the above.

chaptername: 7

questiontype: Multiple Choice

section: 7.3

40. Is the following reaction endothermic or exothermic? How do you know?

C₆H₁₂O₆ + O₂ → 6CO₂ + 6H₂O + heat energy

chaptername: 7

questiontype: Essay

section: 7.4

Feedback: The answer should include the following information: It is exothermic. You know this because heat is produced in the reaction.

41. Is the following reaction endothermic or exothermic? How do you know?

chaptername: 7

questiontype: Essay

section: 7.4

Feedback: The answer should include the following information: The reaction is exothermic. The products have less energy than the reactants, showing that energy was released over the course of the reaction.

42. Explain how a catalyst will affect the activation energy of a chemical reaction.

chaptername: 7

questiontype: Essay

section: 7.4

Feedback: The answer should include the following information: A catalyst will lower the activation energy of a reaction, speeding up the progress of a reaction.

43. Which one of these is not a significant greenhouse gas?

A) carbon dioxide

B) nitrous oxide

C) methane

D) fluorinated gases

E) argon

chaptername: 7

questiontype: Multiple Choice

section: 7.4

44. Methane is produced in fairly large quantities by which animal?

A) dogs

B) cows

C) pigs

D) chickens

chaptername: 7

questiontype: Multiple Choice

section: 7.4

45. Instead of allowing methane to escape into the atmosphere, where it can contribute to global warming, some farmers are

A) trapping it in underground ponds.

B) collecting it and using it to power their farms.

C) using it as a source of fertilizer on their larger sized fields.

D) combining it with zinc and other nutrients to create feed for animals.

chaptername: 7

questiontype: Multiple Choice

section: 7.4