Download Chemistry 21 A - El Camino College

CHEMISTRY 21A
Instructor: Dr. Dragan Marinkovic
Assignment #6
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Student Name / registration number
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Date
1. a) oxidation is:
b) reduction is:
2. The Law of Conservation of Matter states that:
3. The types of nonredox reactions are:
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4. The types of redox reactions are:
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5. Combustion belongs to _________________________ type of reactions.
6. Rusting of iron is (circle the correct answers – there may be more than one correct answer):
a) decomposition reaction
b) combustion reaction
c) single replacement reaction
d) nonredox reaction
e) redox reaction
f) combination reaction
7. What is stoichiometry?
CHEMISTRY 21A
Instructor: Dr. Dragan Marinkovic
Assignment #6
9. a) endothermic reaction is ___________________________________________________________________
b) exothermic reaction is ___________________________________________________________________
10. The percentage yield is _____________________________________________________________________
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Follow this series of questions. When you can answer "yes" to a question, then stop!
1) Does your reaction have oxygen as one of it's reactants and carbon dioxide and water as products? If yes, then it's a combustion
reaction
2) Does your reaction have two (or more) chemicals combining to form one chemical? If yes, then it's a synthesis reaction
3) Does your reaction have one large molecule falling apart to make several small ones? If yes, then it's a decomposition reaction
4) Does your reaction have any molecules that contain only one element? If yes, then it's a single displacement reaction
5) Does your reaction have water as one of the products? If yes, then it's an acid-base reaction
6) If you haven't answered "yes" to any of the questions above, then you've got a double displacement reaction
11. List what type the following reactions are:
a) NaOH + KNO3 --> NaNO3 + KOH
b) CH4 + 2O2 --> CO2 + 2H2O
c) 2Fe + 6NaBr --> 2FeBr3 + 6Na
d) CaSO4 + Mg(OH)2 --> Ca(OH)2 + MgSO4
e) NH4OH + HBr --> H2O + NH4Br
f) Pb + O2 --> PbO2
g) Na2CO3 --> Na2O + CO2
12. Balance the following equations:
a) KClO3(s) → KCl((s) + O2(g)
b) C2H6(g) + O2(g) → CO2(g) + H2O(l)
c) Mg(s) + O2(g) → MgO(s)
d) nitrogen + oxygen → dinitrogen pentoxide
e) CaH2(s) + H2O(l) → Ca(OH)2(s) + H2(g)
f) Al(s) + Fe2O3(s) → Al2O3(s) + Fe(s)
g) aluminum + bromine → aluminum bromide
h) HgNO3(aq) + NaCl(aq) → Hg2Cl2(s) + NaNO3(aq)
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CHEMISTRY 21A
Instructor: Dr. Dragan Marinkovic
Assignment #6
13. Assign oxidation numbers to each element in the following equations and identify the oxidizing and reducing
agents:
a) H2(g) + Cl2(g) → 2HCl(g)
b) H2O(g) + CH4(g) → CO(g) + 3H2(g)
c) CuO(s) + H2(g) → Cu(s) + H2O(g)
d) B2O3(s) + 3Mg(s) → 2B(s) + 3MgO(s)
e) Fe2O3(s) + CO(g) → 2FeO(s) + CO2(g)
f) Cr2O72-(aq) + 2H+(aq) + 3Mn2+(aq) → 2Cr3+(aq) + 3MnO2(s) + H2O(l)
14. Consider all of the following compounds to be water soluble and write the formulas of the ions that would be formed if
the compoundes were disolved in water.
a) LiNO3
b) Na2HPO4
c) Ca(ClO3)2
d) KOH
e) MgBr2
f) (NH4)2SO4
15. In aqueous solutions
a) positive ions are called ____________________________________________
b) negative ions are called ____________________________________________
16. Reactions represented in the following equations take place in water solutions. Write each reaction in total ionic form,
then identify spectator ions and write equations in net ionic form. Solids that do not disolve are designated by (s), gasses
that do not dissolve by (g). In addition, water (H2O) does not dissociate, ie it stays in molecular form.
a) CuSO4(aq) + Zn(s) → Cu(s) + ZnSO4(aq)
b) AgNO3(aq) + NaOH(aq) → AgOH(s) + NaNO3(aq)
c) BaCO3(s) + 2HCl(aq) → BaCl2(aq) + CO2(g) + H2O(l)
d) 2HNO3(aq) + Ca(OH)2(aq) → Ca(NO3)2(aq) + 2H2O(l)
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CHEMISTRY 21A
Instructor: Dr. Dragan Marinkovic
Assignment #6
17. The human body cools itself by the evaporation of perspiration. Is the evaporation process endothermic or
exothermic?
Explain.
18. Antacids are used to neutralize stomach acid. The active ingerdiend of most antacids is calcium carbonate. How many
grams of CaCO3 is necessary to neutralize 0.25 g of HCl? How many moles of carbon dioxide will be generated? Balance
the given reaction before doing calculations.
CaCO3(s) + HClIaq) → CaCl2 + CO2(g) + H2O(l)
19. A 2.0 g sample of calcium metal was reacted with (excess) of oxygen. The weight of isolated calcium oxide was 2.26 g.
What was the percentage yield of the reaction? Balance the given reaction before doing calculations.
Ca(s) + O2(g) → CaO(s)
20. Sucrose, white sugar (C12H22O11), provides 4 calories (cal) per gram. How many calories will be proivided from one mol
of sucrose?
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