Arkansas State University  Department of Chemistry and Physics
CHEM2004	Exam 7

CHEM2004                                                               Name _________________________

Exam 7                                                                       Fall 2009

1.         Based on the flow charts, match the reagent/ test first used to identify the ion listed below: (20 points)

a. chloride             b. sulfide        c. hydroxide      d. carbonate      e. flame test

_____ cadmium                                      _____ copper

_____ mercury(II)                                   _____ nickel

_____ potassium                                    _____ calcium

_____ aluminum                                     _____ silver

_____ arsenic                                         _____ sodium

2.         List three ions that give a yellow precipitate with sulfide.  Write a net ionic equation for each:                        (9 points)

            a)______________________________________________________________

            b)______________________________________________________________

            c)______________________________________________________________

3.         Several of the ions give complex cations with ammonia.  List two of them and give their formulas and color of the ions:  (6 points) ________________________________________________________________           

4.         Give the color of the flame for each ion below:          (10 points)

barium -

sodium -

calcium -

lithium -

copper  -

5.         Which metal carbonate is                                    (10 points)

pink? ________________________________           

blue? ________________________________

purple? ________________________________

orange? ________________________________

pale green? ________________________________

6.         Give the net ionic equation for the reaction of each of the following with sodium hydroxide and give the colors for all species:       (10 points)

a) copper

b) cadmium

7.         You have two samples, one is FeS and the other is CoS.  What reagent could you add that would distinguish between the two compounds.

       Explain how this would identify the compounds.  (6 points)

8.         Give the color for:                          (10 points)

Mg⁺²

Co⁺²

Cr⁺³

Ni⁺²

Fe⁺²

9.         Two metals give oxides when reacted with hydroxide ion, list them:  (4 points)            ____________________________________

10.       Three metals give hydroxides when reacted with sulfide ion, list them:  (6 points)            ____________________________________

11.       You are given an unknown sample that contains two cations.  Based on the following information, identify the cations.  (10 points)

            a) a white precipitate forms with the addition of chloride.  This precipitate does not react with ammonia. 

            b) addition of chromate gives a yellow precipitate.

            c) addition of sulfide gives a black precipitate.

            d) removal of the white precipitate from part and testing the solution gives a white precipitate upon addition of sulfate.

            e) flame test gives green color

The two ions are: ___________ and ___________