Sample CHEM 101 Exam Paper 2

Duration 1 hour 30 minutes

Section A – Multiple Choice and Short Answer

1.      What is the solvent in an aqueous solution?

2.      Of the species below, only ___ is not an electrolyte.

a.    HCl

b.    Rb2SO4

c.    Ar

d.    KOH

e.    NaCl

3.      Which one of the following compounds is insoluble in water?

a.    Na2CO3

b.    K2SO4

c.    Fe(NO3)3

d.    ZnS

e.    Ag2CO3

4.      What is the concentration of chloride ions in a 0.193 M solution of potassium chloride?

a.    0.0643 M

b.    0.386 M

c.    0.0965 M

d.    0.579 M

e.    0.193 M

5.      The point in a titration at which the indicator changes is called the ___.

a.    equivalence point

b.    indicator point

c.    standard point

d.    end point

e.    volumetric point

6.      Units of energy include ___.

A. Newton

B. Joule

C. Calorie

a.    A only

b.    B only

c.    C only

d.    B and C only

e.    A and B only

7.      Which one of the following is an exothermic process?

a.    ice melting

b.    water evaporating

c.    boiling soup

d.    combustion of methane

e.    Ammonium thiocyanate and barium hydroxide are mixed at 25 0C: the temperature drops

8.      ∆H for the reaction

IF5 (g)                            IF3 (g) + F2 (g)    

is ___ kJ, given the data below

IF(g) +   F2 (g)                             IF3 (g)                ∆H = -390 kJ

IF(g)  + 2F2 (g)                           IF5 (g)                ∆H = -745 kJ

a.    +355

b.    -1135

c.    +1135

d.    +35

e.    -35

Show calculation.

9.      Given the data in the table below, ∆HRXN for the reaction

Ca(OH)2 + 2H3AsO4                                Ca(H2AsO4)2 + 2H2O

is ___ kJ.

Substance

∆Hof (kJ/mol)

Ca(OH)2

-986.6

H3AsO4

-900.4

Ca(H2AsO4)2

-2346.0

H2O

-285.9

a.    -744.9

b.    -4519

c.    -4219

d.    -130.4

e.    -76.4

Show calculations

10.  The specific heat capacity of lead is 0.13 J/g-K. How much heat (in J) is required to raise the temperature of 15g of lead from 22 0C to 37 0C?

a.    2.0

b.    -0.13

c.    5.8 x 10-4

d.    29

e.    0.13

Show calculations

Section B – Structured Questions

11.  Write the net ionic equation for the precipitation reaction that occurs when solutions of calcium chloride and sodium carbonate are mixed.

12.  What is the oxidation state of the boldfaced element in each of the following?

            a. SO3

            b. COCl2

            c. MnO4-

            d. HBrO

            e. As4

13.  a) Starting with solid sucrose, C12H22O11, describe how you would prepare 125 mL of 0.150 M sucrose solution. (b) Describe how you would prepare 400.0 mL of 0.100 M C12H22O11 starting with 2.00 L of 1.50 M C12H22O11.

14.  What mass of NaCl is required to precipitate all the silver ions from 20.0 mL of 0.100 M AgNO3?

15.  Define the following terms:

            a. Solution

            b. Electrolyte

16. Hydrogen peroxide can decompose to water and oxygen by the reaction

2H2O2                                         2H2O + O2                 ∆H = -196 kJ

Calculate the value of q when 10.00 g of H2O decomposes at constant pressure.

17. Explain the following terms:

            a. Thermodynamics

            b. Kinetic Energy

            c. Potential Energy

            d. The First Law of Thermodynamics

            e. Standard Enthalpy of Formation.

18. Briefly explain how a Bomb Calorimeter works.

19. Calculate ∆H for the reaction

NO(g)    + O(g)                                 NO2(g)

given the following information:

NO(g)    +   O3 (g)                                   NO2(g) + O2 (g)   ∆H = -198.9 kJ

O3 (g)                                 3/2 O2 (g)        ∆H = - 142.3 kJ

O2 (g)                                 2 O (g)              ∆H = 495.0 kJ

Bonus Question

Although, pure water is a poor conductor of electricity, we are cautioned not to operate electrical appliances around water. Why?