Chem Chapter 3 and 4 Test

1. Oxidation Number of Mn in KMnO4:

   • +7.

2. Redox Reaction: Given: HCrO4 – + H2S → Cr2O3 + SO4 2–

   • Cr is reduced while S is oxidized.

3. Spontaneous Reactions: Incorrect Statement: Spontaneous reactions are always fast.

   • Correct Information: Can be fast or slow.

4. pH Neutral Solution: Incorrect Statement: Must not contain H+ or OH– ions.

   • Correct Information: Contains equal amounts of H+ and OH– ions.

5. Definition of Molarity: Incorrect Statement: Defined per 2 liters.

   • Correct Information: Defined as moles of solute per 1 liter.

6. Limiting Reactant: Incorrect Statement: The product that is completely consumed.

   • Correct Information: The reactant that is completely consumed.

7. Theoretical Yield of Muffins: Recipe: 2 cups flour + 1 egg + 3 oz blueberries = 4 muffins.

   • Incorrect Statement: Theoretical yield is 10 muffins.

   • Correct Information: Theoretical yield is 16 muffins.

8. Dilution Process:

   • Upon dilution, volume increases and concentration decreases.

9. Acid-Base Neutralization:

   • Typically exothermic.

10. Actual Yield vs Theoretical Yield:

    • Correct Information: Actual yield is the same as theoretical yield if reaction goes to completion with no loss of product.

Multiple-Choice Questions

11. Classify the Reaction: Reaction: KOH(aq) + HCl(aq) → KCl(aq) + H2O(l)

    • Correct Answer: Strong acid-strong base reaction.

12. Oxidation Number of O in H2O2:

    • Options:

      Correct Answer: –2, –2, oxidizing agent.

13. Redox Reaction Analysis: Given: Sn(s) + HCl(aq) → ?

    • Select all that apply:

    • Correct Answer: i., ii., iv., and v.

14. Oxidized Element in Reaction: Reaction: Fe + CuSO4 → Cu + FeSO4

    • Correct Answer: Fe.

15. Identifying Redox Reactions:

    • Choices include: (A) CaCO3(s) → CaO(s) + CO2(g),

    • (B) CaO(s) + SO2(g) → CaSO3(s),

    • (C) CaCl2(s) → Ca(s) + Cl2(g),

    • (D) 3 Ca(s) + N2(g) → Ca3N2(s), (E) Ca2+(aq) + CO3 2–(aq) → CaCO3(s)

    • Correct Answer: A) (A), (C), and (D).

16. Insoluble Ionic Compound in Water:

    • Correct Answer: BaSO4.

17. Conjugate Base Identification: Reaction: CO3 2– + H2SO4 ⇌ HSO4 – + HCO3 –

    • Correct Answer: HCO3 –.

18. Conjugate Acid-Base Pair:

    • Correct Answer: H2O2 & HO2 –.

19. pH Classification of Substances:

    • Correct Answer: Urine, pH = 5.93 (unambiguously acidic).

20. Heat Transfer Process:

    • Correct Answer: endothermic.

Calculation Problems

21. Molecules of Ozone in Sample: Given: 5.00 × 10–10 mol in 1.00 mL.

    • Correct Answer: 3.01 × 1014 molecules.

22. Most Moles of Compound:

    • Choices: (A) 163.0 g of Fe2O3

    • (B) 75.0 g of CaS

    • (C) 150.0 g of BaO.

    • Correct Answer: Impossible to determine without density.

23. Definition of Molarity:

    • Correct Answer: moles of solute dissolved in 1 L of solution.

24. Most Moles of Solute Compound:

    • Choices: A) 23.5 mL of 0.0100 M K3PO4(aq)

    • B) 32.0 mL of 0.00600 M Mg(NO3)2(aq)

    • C) 5.00 mL of 0.0500 M LiOH(aq).

    • Correct Answer: Impossible to determine without density.

25. Mass of NaCl Required for Solution: Required: 250.0 mL of 0.0500 M NaCl.

    • Correct Answer: 58.5 g.

26. Molar Concentration of NaOH Solution: Given: 120 g of NaOH in 500 mL.

    • Approximate Answer: About 1 M.

27. Neutralizing Stomach Acid with CaCO3: Given: 500 mg of CaCO3.

    • Correct Answer: 50 mL.

28. Volume of HCl Needed to Neutralize NaHCO3: Given: 17.2 g of NaHCO3.

    • Correct Answer: 206 mL.

29. Percent Yield of Bromomethane Production: Given: 12.23 g of CH3Br is produced.

    • Correct Answer: 40.9%.

30. Mass Loss Explanation in Mg and O Reaction:

    • Correct Answer: It contains. The recipe calls for 2 cups of flour + 1 egg + 3 oz of blueberries, which yields. The actual yield is the same as the theoretical yield if not all oxygen reacted as it is in excess.