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1. Which of the following pairs are both electrolytes? NaOH and SO2 B. H2SO4 and

ID: 955707 • Letter: 1

Question

1. Which of the following pairs are both electrolytes?

NaOH and SO2   B. H2SO4 and NH4Cl   C. CH3OH and C2H5OH D. HNO2 and NO2   E. CO2 and H2CO3

2. Which of the following is a weak electrolyte?

HBr(aq)                       B. KOH(aq)                C. HNO3                     D. H3PO4                    E. Ba(OH)2

3. For which of the following pairs are both compounds insoluble in water?

NaBr, Na2SO4 B. Na2CO3, CaCO3   C. Fe2(CO3)3, Ba3(PO4)2 D. Na3PO4, Ca3(PO4)2 E. PbSO4, MgSO4

4. Which of the following is a weak acid?

A. HClO3                    B. HCl                         C. HClO4                    D. HNO3                     E. HF

5. Which of the following is a Brønsted acid?

A. NH4+(aq)                B. CH3COO– (aq)       C. NH3            (aq)                  D. OH–            (aq)                  E. Na+(aq)

6. Which of the following is a Brønsted base?

A. NH4+(aq)                B. Na+(aq)                   C. HNO3(aq)               D. NH3(aq)                 E. CH3COOH(aq)

7. In the reaction: NH3(aq) + H2O NH4+(aq) + OH

A. In this reaction H2O is the Brønsted

acid     B. NH3 is the Brønsted acid and NH4+ is the Brønsted base

C. OH– is a proton donor                               D. NH4+ is a Brønsted base                           

E. NH4+ is the Brønsted acid and NH3 is the Brønsted base, they are a conjugate acid-base pair

8. The oxidation numbers of S in SO32– and,SO42– are:

A. +2 and + 4              B. +3 and +6               C. +4 and +6               D. +6 and +8               E. –4 and –6

9. The oxidation number of Cr in the dichromate ion, Cr2O72– is:

A. +6                           B. +5                           C. +4                           D. –4                           E. +7

10. In the reaction: FeO + CO Fe + CO2

A. Fe is the oxidizing agent     B. CO is reduced         C. O2– is oxidized        D. CO is the reducing agent

Fill in the answer for the following questions.

11. Chang 4.47 (with some changes).         Give the oxidation number of the underlined element in the following compounds and ions:

            CO2                CH4                C2H2                CrO3               K2CrO4           NaHCO3         PO43–

Ox.#: ____                 ____                ____                ____                ____                ____                ____

12. Circle the correct answer for each

            OH– is a                     Brønsted acid / Brønsted base / can be both

            H3O+ is a                     Brønsted acid / Brønsted base / can be both

            CO32– is a                    Brønsted acid / Brønsted base / can be both

            HCO3– is a                  Brønsted acid / Brønsted base / can be both

            PO43– is a                    Brønsted acid / Brønsted base / can be both

            H3PO4 is a                   Brønsted acid / Brønsted base / can be both

            H2PO4– is a                 Brønsted acid / Brønsted base / can be both

            CH3COOH is a           Brønsted acid / Brønsted base / can be both

            CH3COO– is a             Brønsted acid / Brønsted base / can be both

            SO42– is a                     Brønsted acid / Brønsted base / can be both

13. Write the balanced molecular reaction and the net ionic reaction for the reaction between BaCl2 and Na3PO4 in aqueous solution:

Molecular reaction:     ____BaCl2(aq) + ____Na3PO4(aq) ____ ___________ + ____ __________   

Net ionic reaction:

14. Chang 4.55 (with some additions). Classify the following reactions as: acid-base, precipitation, combustion, combination, and displacement or disproportionation reaction:

2H2O2 2H2O + O2                                     _______________________________ reaction      

Mg + 2AgNO3 Mg(NO3)2 + 2Ag              _______________________________ reaction

BaCl2(aq) + MgSO4(aq) BaSO4(s) + MgCl2(aq) __________________________ reaction

NH3(aq) + HBr(aq) NH4Br(aq)                _______________________________ reaction

2CO(g) + O2 2CO2(g)                                _______________________________ reaction      

H2 + Br2 2HBr                                           _______________________________ reaction      

Explanation / Answer

1. B. H2SO4 and NH4Cl are both electrolytes.
2. D. H3PO4 is a weak electrolyte.

4. E. HF is a weak acid.
5. A. NH4+(aq) is a Brønsted acid. It is proton donor.
6. D. NH3(aq) is a Brønsted base. It is proton acceptor.
7. A. In this reaction H2O is the Brønsted acid.
E. NH4+ is the Brønsted acid and NH3 is the Brønsted base, they are a conjugate acid-base pair.