QUIZ     October                                         CHEM100.11     

 

                                                                         Name: ___________________

                                                                                    Family name     First name

 

PLEASE READ THIS BEFORE YOU BEGIN:  This test comprises 7 pages (including this page) and a Periodic Table, Solubility Table and Activity Series of Metal Table.  Please make sure you have a complete exam and that you have filled in the information above.  All questions are to be answered on the question sheets either by circling the appropriate answer on the multiple-choice questions or by writing in your solutions for the short and long answer questions.   Calculators are permitted.  You have 50 min. 

 

MULTIPLE-CHOICE QUESTIONS (circle the letter (one!) which corresponds to the suitable answer)

1.      The density of silver is 10.5 g/cm3. A piece of silver with a mass of 61.3 g would occupy a volume of _____ cm3  {5}

A)      0.171

B)       644

C)      10.5

D)      0.00155

E)       5.84

 

2.      There are ______________ mol of bromide ions in 0.500 L of a 0.300M solution of AlBr3  {5}

(A)  0.150

(B)   0.0500

(C)  0.450

(D)  0.165

(E)   0.500

3.      Which atom has the smallest number of neutrons? {5}

A)    Carbon-14

B)     Nitrogen-14

C)    Oxygen-16

D)    Fluorine-19

E)     Neon-20

 

4.      Which group in the periodic table contains only nonmetals?    {5}

A)    1A

B)     6A

C)    2A

D)    5A

E)     8A

 

5.      The name of the binary compound N­2O4 is ______{5}

A)    Nitrogen oxide

B)     Nitrous oxide

C)    Nitrogen (III) oxide

D)    Dinitrogen tetroxide

E)     Oxygen nitride

 

 

6.      The net ionic equation for the dissolution of zinc metal in aqueous hydrobromic acid is          {5}

A)    Zn (s) + 2Br- (aq) à ZnBr2 (aq)

B)     Zn (s) + 2HBr- (aq) à ZnBr2 (aq) + 2H+ (aq)

C)    Zn (s) + 2HBr- (aq) à ZnBr2 (s) + 2H+ (aq)

D)    Zn (s) + 2H+ (aq) à Zn2+ (aq) + H2 (g)

E)     Zn (s) + H+ (aq) à Zn2+ (aq) + H- (aq)

 

SHORT ANSWERS {10 scores each}

7.      {10} What is the concentration (M) of a NaCl solution prepared by dissolving 9.3 g of NaCl in sufficient water to give 350 mL of solution?

 

 

 

 

 

 

 

 

 

 

 

8. {10} Complete and balance the following equations. Identify the oxidizing and reducing agents:                                                                                                       

  CN – (aq) +    Fe 3+ (aq)  à   Fe2+ (aq)  +      CNO- (aq)  (basic solution)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Oxidizing agent___________________________________

 

Reducing agent____________________________________

 

 

 

9. {10} A 17.5 sample of sulfuric acid, H2SO4, solution required 29.6 mL of 0.250 M NaOH for neutralization. Write down the balanced equation and calculate the concentration (M) of H2SO4.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Longer Problems {15}

10.  {15}  Magnesium nitride, Mg3N2 reacts with H2O to produce NH3 and magnesium oxide, MgO.  How many moles of MgO can be produced by the reaction of  3.82 g of Mg3N2 and 7.73g of water if the percent yield of this reaction is 80%.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11. {15} Combustion analysis of toluene, a common organic solvent, gives 5.86 mg of CO2 and 1.37 mg of H2O. Toluene contains only C and H atoms.  What is the empirical formula of the compound?