CHEM 121
Fall 2010
Your Name:______________
Quiz 6 – Reactions (Due Monday Nov 29th)
15 pts + 3 extra credit pts
1. Balance the following reactions:
a. Li2CO3(aq) + Mg(NO3)2(aq)  LiNO3(aq) + MgCO3(s)
b. MnO2(s) + Al(s)  Al2O3(s) + Mn(s)
c. NO2(g) + O2(g)  N2O5(g)
2. Determine if the reactions in question 1 are single replacement, double replacement,
combination or decomposition.
a. ______________________
b. ______________________
c. ______________________
3. Write the total ionic and net ionic equations for reactions 3a – c. Remember that
only species that are written as aqueous dissociate.
a. CaF2(g) + H2SO4(aq)  CaSO4(s) + 2 HF(g)
Total ionic:
Net ionic:
b. 4 NaClO3(aq)  3 NaClO4(s) + NaCl(aq)
Total ionic:
Net ionic:
4. Determine the oxidation number of each atom in the following compounds or ions.
a. Al2O3
b. Cr2O72c. (NH4)2SO4
5. Determine which what atom was reduced and oxidized in each of the following
equations:
a. 4 NaClO3(aq)  3 NaClO4(s) + NaCl(aq)
b. 2 Mg(ClO3)2(s)  2 MgCl2(s) + 3 O2(g)
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6. From the following equation determine how many moles lithium hydroxide (LiOH) are
necessary to produce 1 mol of lithium sulfate (Li2SO4).
H2SO4(aq) + 2 LiOH(aq)  Li2SO4(aq) + 2 H2O(l)
7. Again using the equation from problem 6, answer the following questions. If 5.3 g of
H2SO4 and 3.75 g of LiOH were used, which one is the limiting reagent. For
questions a. and b. show how much of Li2SO4 in grams can be produced:
a. Starting from compound H2SO4:
b. Starting from compound LiOH:
c. Which compound is your limiting reagent?
8. After performing the reaction in question 6 using the amounts given to you in
question 7, you isolate 4.67g of the product Li2SO4. Answer the following questions:
a. What is your theoretical yield of Li2SO4?
b. What is your percent yield of Li2SO4?
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