Ch. 8 & 18 aqueous reactions                          test     [70 points]                   honors Chem

 

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

 

                                                                                                Signature:  ___________________

 

1. Use the following hypothetical experimental data and the below graph to estimate the concentration of vit C (in mg / mL) of a fruit.  [10 points]

 

[vit C]  (mg / mL)

# drops of I2

0

1

0.125

4

0.25

8

0.50

16

1.0

31

Fruit

20

 

 2.  What is the oxidation number of __.  [10 points]

a.  Mn in KMnO4 is  ______

 

b.  Sulfur in the sulfate ion is ____

 

c.  C in CH3OH is __

 

d.  Nitrogen in nitrogen gas is  ____

 

e.  Nitrogen in barium nitrate is  ____

 

3.  Identify the atom (in the molecule) that are involved in oxidation and reduction (in the both the reactant and product) in the following redox reactions; include the oxidation number near the atom that is oxidized or reduced.  [12 points]

 

  1.  CH3OH   +   O2   à   CO2   +   H2O

 

 

Oxidized:  _______________________

 

Reduced:  _______________________

 

MnO4 -    +  Zn  +  H+  à  H2O  +  Mn2+  +  Zn2+

 

 

Oxidized:  _______________________

 

Reduced:  _______________________

 

4. Write the net ionic equation for the following reactants; if there is no reaction, then write “no reaction”.    [15 points]

a.  mix aqueous solutions of calcium nitrate and potassium phosphate

 

b. mix aqueous solutions of sodium carbonate and lithium hydroxide

 

c.  add solid zinc into an aqueous solution of hydrogen chloride

 

d.  the combustion of CH4

 

e. mix aqueous solutions of sodium sulfate and barium nitrate

 

5. Identify the type(s) of reactions using the below list of possible reactions.   [10 points]

 

double replacement reaction                            single replacement reaction

combustion reaction                                        redox reaction

acid / base reaction                                          synthesis reaction

precipitation reaction                                       decomposition reaction

 

a. C6H12O6  +  O2  à  CO2  +  H2O is  ______________________________

 

b. Cu  +  HNO3  à  Cu(NO3)2  +  NO2  +  H2O is  _____________________

 

c. Zn  +  HBr  à  ZnBr2  +  H2  is  _________________________________

d.  mixing aqueous solution of hydrogen nitrate and potassium hydroxide is  _______________________

 

e.  mixing aqueous solutions of magnesium nitrate and sodium carbonate is ________________________

 

 6. Describe an experimental protocol, based on solubility rules, to differentiate between an aqueous solution of __; include an interpretation of your observations.   [10 points]

a. Sodium sulfate versus sodium sulfide

 

b.  Magnesium nitrate versus barium nitrate

 

7. What is the solubility rule for hydroxides; include all exceptions.   [3 points]