Ch. 8 & 18  chemical reactions                       test     [60 points]                   honors Chem

For problems involving calculations, show your work in an organized manner, include any relevant equation (or formula and conversion factor(s)), put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.              

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.

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1.  Indentify the type(s) of reactions; use the following choices:   [10 points]

• acid-base
• combustion
• decomposition
• double replacement
• precipitation
• redox
• single replacement 
• synthesis 

a.  AgNO₃  +  Sn  à  Sn(NO₃)₂  +  Ag                      Rx type(s)  =

b.  HNO₃  +  NaOH  à  H₂O  +  NaNO₃                  Rx type(s)  =

c.  CH₃OH  +  O₂  à  CO₂  +  H₂O                            Rx type(s) =   

d.  O₂  +  H₂  à  H₂O                                                 Rx type(s) =

e.  CH₃NH₂  à  C  +  H₂  +  N₂                                 Rx type(s) =

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

a.  carbon in carbon tetrachloride

b.  Cr in Na₂Cr₂O₇

c.  S in sulfate

d.  phosphorus in phosphate

e.  Fe in Fe(NO₃)₂

3.  Write the net ionic equation.  Need not write a balanced chemical equation, but the chemical formula has to be correct; if there is no reaction, then write “no reaction”.   [15 points]

a.  mix aqueous solutions of sodium bicarbonate and nitric acid (i.e. hydrogen nitrate)

b.  add copper metal to a solution of hydrochloric acid

c.  mix aqueous solutions of calcium nitrate and potassium carbonate

d.  the combustion of methane, CH₄

e.  mix aqueous solutions of barium chloride and lithium iodide

4.  Identify the species that is oxidized and species that is reduced in the following reactions.  [10 points]

a.  C₂H₆  +  O₂  à  CO₂  +  H₂O

b.  (hydrogen peroxide)  H₂O₂  à  H₂O  +  O₂

c.  Zn(NO₃)₂  +  Cu  à  Cu(NO₃)₂  +  Zn

d.  N₂  +  H₂  à  NH₃

e.  HI  +  Cl₂  à  I₂  +  HCl

5.   An unknown sample contains only 1 of the below chemicals:

BaCl₂                           Na₂CO₃

Ba(OH)₂                      NaI

                                    NaOH

                                                Na₂ SO₄

Based on the following sequential experimental observations, what is / are the possible compound(s) in the sample (after each sequential observation) ?  The addition of  ___ to the sample  ___.     [15 points]

a.  K₂ SO₄ . . . does not produce a precipitate

b.  Zn(NO₃)₂ . . . produces a precipitate

c.  CaCl₂   . . . does not produce a precipitate.