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Online Study Guide - Stoichiometry - Chem 1


Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 1. 
Which branch of chemistry deals with the mass relationships of elements in compounds and the mass relationships among reactants and products in chemical reactions?
a.
qualitative analysis
c.
chemical kinetics
b.
entropy
d.
stoichiometry
 

 2. 
A balanced chemical equation allows one to determine the
a.
mole ratio of any two substances in the reaction.
b.
energy released in the reaction.
c.
electron configuration of all elements in the reaction.
d.
mechanism involved in the reaction.
 

 3. 
To balance a chemical equation, it may be necessary to adjust the
a.
coefficients.
c.
formulas of the products.
b.
subscripts.
d.
number of products.
 

 4. 
A chemical equation is balanced when the
a.
coefficients of the reactants equal the coefficients of the products.
b.
same number of each kind of atom appears in the reactants and in the products.
c.
products and reactants are the same chemicals.
d.
subscripts of the reactants equal the subscripts of the products.
 

 5. 
Which equation is not balanced?
a.
stoich_files/i0060000.jpg
c.
stoich_files/i0060001.jpg
b.
stoich_files/i0060002.jpg
d.
stoich_files/i0060003.jpg
 

 6. 
Which coefficients correctly balance the formula stoich_files/i0070000.jpg?
a.
1,2,2
c.
2,1,1
b.
1,1,2
d.
2,2,2
 

 7. 
When the formula equation stoich_files/i0080000.jpg is correctly balanced the coefficient of Fe is number
a.
3.
c.
7.
b.
2.
d.
9.
 

 8. 
Given the equation stoich_files/i0090000.jpg, the starting mass of A, and its molar mass, and you are asked to determine the moles of C produced, your first step in solving the problem is the multiply the given mass of A by
a.
stoich_files/i0090001.jpg
c.
stoich_files/i0090002.jpg
b.
stoich_files/i0090003.jpg
d.
stoich_files/i0090004.jpg
 

 9. 
The units of molar mass are
a.
g/mol.
c.
amu/mol.
b.
mol/g.
d.
amu/g.
 

 10. 
In the reaction represented by the equation N2 + 3H2 ® 2NH3, what is the mole ratio of nitrogen to ammonia?
a.
1:1
c.
1:3
b.
1:2
d.
2:3
 

 11. 
In the reaction represented by the equation 2Al2O3 ® 4Al + 3O2, what is the mole ratio of aluminum to oxygen?
a.
10:6
c.
2:3
b.
3:4
d.
4:3
 

 12. 
The Haber process for producing ammonia commercially is represented by the equation N2(g) + 3H2(g) ® 2NH3(g). To completely convert 9.0 mol hydrogen gas to ammonia gas, how many moles of nitrogen gas are required?
a.
1.0 mol
c.
3.0 mol
b.
2.0 mol
d.
6.0 mol
 

 13. 
In the equation 2KClO3 ® 2KCl + 3O2, how many moles of oxygen are produced when 3.0 mol of KClO3 decompose completely?
a.
1.0 mol
c.
3.0 mol
b.
2.5 mol
d.
4.5 mol
 

 14. 
For the reaction represented by the equation C + 2H2 ® CH4, how many moles of hydrogen are required to produce 10 mol of methane, CH4?
a.
2 mol
c.
10 mol
b.
4 mol
d.
20 mol
 

 15. 
For the reaction represented by the equation 2H2 + O2® 2H2O, how many moles of water can be produced from 6.0 mol of oxygen?
a.
2.0 mol
c.
12 mol
b.
6.0 mol
d.
18 mol
 

 16. 
For the reaction represented by the equation N2 + 3H2 ® 2NH3, how many moles of nitrogen are required to produce 18 mol of ammonia?
a.
9.0 mol
c.
27 mol
b.
18 mol
d.
36 mol
 

 17. 
For the reaction represented by the equation AgNO3 + NaCl ® NaNO3 + AgCl, how many moles of silver chloride, AgCl, are produced from 7.0 mol of silver nitrate AgNO3?
a.
1.0 mol
c.
7.0 mol
b.
2.3 mol
d.
21 mol
 
 
Use the table below to answer the following questions.

Element
Symbol
Atomic Mass
Bromine
Br
79.90
Calcium
Ca
40.08
Carbon
C
12.01
Chlorine
Cl
35.45
Cobalt
Co
58.93
Copper
Cu
63.55
Fluorine
F
19.00
Hydrogen
H
1.01
Iodine
I
126.90
Iron
Fe
55.85
Lead
Pb
207.2
Magnesium
Mg
24.30
Mercury
Hg
200.59
Nitrogen
N
14.01
Oxygen
O
15.00
Potassium
K
39.10
Sodium
Na
22.99
Sulfur
S
32.01
 

 18. 
For the reaction represented by the equation 2H2 + O2 ® 2H2O, how many grams of water are produced from 6.00 mol of hydrogen?
a.
2.00 g
c.
54.0 g
b.
6.00 g
d.
108 g
 

 19. 
For the reaction represented by the equation 2Na + 2H2O ® 2NaOH + H2, how many grams of sodium hydroxide are produced from 3.0 mol of sodium with an excess of water?
a.
40. g
c.
120 g
b.
80. g
d.
240 g
 

 20. 
For the reaction represented by the equation SO3 + H2O ® H2SO4, how many grams of sulfur trioxide are required to produce 4.00 mol of sulfuric acid in an excess of water?
a.
80.0 g
c.
240. g
b.
160. g
d.
320. g
 

 21. 
For the reaction represented by the equation 2Fe + O2 ® 2FeO, how many grams of iron(II) oxide are produced from 8.00 mol of iron in an excess of oxygen?
a.
71.8 g
c.
712 g
b.
575 g
d.
1310 g
 

 22. 
For the reaction represented by the equation 2Na + Cl2 ® 2NaCl, how many grams of chlorine gas are required to react completely with 2.00 mol of sodium?
a.
35.5 g
c.
141.8 g
b.
70.9 g
d.
212.7 g
 

 23. 
For the reaction represented by the equation 2HNO3 + Mg(OH)2 ® Mg(NO3)2 + 2H2O, how many grams of magnesium nitrate are produced from 8.00 mol of nitric acid, HNO3, and an excess of Mg(OH)2?
a.
148 g
c.
593 g
b.
445 g
d.
818 g
 

 24. 
For the reaction represented by the equation CH4 + 2O2 ® CO2 + 2H2O, how many moles of carbon dioxide are produced from the combustion of 100. g of methane?
a.
6.23 mol
c.
12.5 mol
b.
10.8 mol
d.
25 mol
 

 25. 
For the reaction represented by the equation Pb(NO3)2 + 2KI ® PbI2 + 2KNO3, how many moles of lead(II) iodide are produced from 300. g of potassium iodide and an excess of Pb(NO3)2?
a.
0.904 mol
c.
3.61 mol
b.
1.81 mol
d.
11.0 mol
 

 26. 
For the reaction represented by the equation Cl2 + 2KBr ® 2KCl + Br2, how many moles of potassium chloride are produced from 119 g of potassium bromide?
a.
0.119 mol
c.
0.581 mol
b.
0.236 mol
d.
1.00 mol
 

 27. 
For the reaction represented by the equation 3Fe + 4H2O ® Fe3O4 + 4H2, how many moles of iron(III) oxide are produced from 500. g of iron in an excess of H2O?
a.
1.04 mol
c.
8.95 mol
b.
2.98 mol
d.
12.98 mol
 

 28. 
For the reaction represented by the equation 2KlO3 ® 2KCl + 3O2, how many moles of potassium chlorate are required to produce 250. g of oxygen?
a.
2.00 mol
c.
4.97 mol
b.
4.32 mol
d.
5.21 mol
 

 29. 
Ozone, O3, is produced by the reaction represented by the following equation:
stoich_files/i0310000.jpg
What mass of ozone will form from the reaction of 2.0 g of NO2 in a car's exhaust and excess oxygen?
a.
1.1 g O3
c.
2.1 g O3
b.
1.8 g O3
d.
4.2 g O3
 

 30. 
For the reaction represented by the equation Cl2 + 2KBr ® 2KCl + Br2, how many grams of potassium chloride can be produced from 300. g each of chlorine and potassium bromide?
a.
98.7 g
c.
188 g
b.
111 g
d.
451 g
 

 31. 
How many moles of carbon dioxide is produced when 10.4 mol of propane gas is burned in excess oxygen?
a.
0.288 mol
c.
31.2 mol
b.
3.46 mol
d.
52.0 mol
 

 32. 
How many grams of water are produced when 2.50 mol oxygen reacts with hydrogen?
a.
0.277 g
c.
45.0 g
b.
22.5 g
d.
90.0 g
 

 33. 
What is the mass of potassium chloride when 2.50 g of potassium reacts with excess of chlorine gas?
a.
4.77 g
c.
9.52 g
b.
8.57 g
d.
728 g
 

 34. 
How many moles of carbon dioxide are produced when 8.30 mol of ethanol reacts with excess of oxygen?
a.
0.241 mol
c.
16.6 mol
b.
4.15 mol
d.
24.9 mol
 

 35. 
Calculate the mass of citric acid when 2.60 mol of sucrose gas reacts with oxygen.
a.
0.769 g
c.
999 g
b.
1.30 g
d.
499 g
 
 
8 KClO3  +  C12H22O11  stoich_files/i0380000.jpg 8 KCl  +  12 CO2  +  11 H2O
 

 36. 
Using the above reaction, if 3.0 moles of potassium chlorate are used, how many moles of water would be produced?
a.
2.2
c.
502
b.
4.1
d.
0.0020
 

 37. 
Using the above reaction, how many moles of potassium chlorate are required to produce 18.0 g of water?
a.
89.0     
c.
54.1
b.
0.726
d.
6.72
 

 38. 
Ammonia (NH3) is used to make fertilizer.  If you have 2.00 x 10 3g of N2 how many grams of ammonia can be produced?
                                    N2     +     3H2     stoich_files/i0410000.jpg      2NH3
a.
2430     
c.
143
b.
4870
d.
285
 

 39. 
Write the reaction for the combustion of C4H6, balance the equation, and determine the coefficient of H2O.
a.
3
c.
2
b.
6
d.
11
 

 40. 
How many atoms of Cu are in 4.00 moles?  
a.
254     
c.
2.41 x 1024     
b.
0.00393
d.
6.64 x 10-24
 

 41. 
How many grams of CH3Br could be made from 10.0 g of CH3OH and excess PBr3?
                        3 CH3OH     +     PBr3     stoich_files/i0440000.jpg     3 CH3Br     +     P(OH)3
a.
23.4
c.
4.27
b.
0.0428
d.
0.234
 

 42. 
How many moles are in 1.2 X 1024 molecules of water?
a.
0.503     
c.
7.72 x 1047
b.
1.38 x 10-48
d.
1.99
 

 43. 
Mole ratios for a reaction are obtained from what?
a.
Avogadro’s number
c.
balanced chemical equation
b.
subscripts
d.
charges
 

 44. 
How many moles of carbon dioxide is produced when 10.4 mol of propane gas is burned in excess oxygen?
a.
0.288 mol
c.
31.2 mol
b.
3.46 mol
d.
52.0 mol
 

 45. 
How many grams of water are produced when 2.50 mol oxygen reacts with hydrogen?
a.
0.277 g     
c.
45.0 g
b.
22.5 g
d.
90.0 g
 

 46. 
Calculate the number of moles in 250.0g of potassium chlorate (KClO3).
a.
3.35
c.
8.25
b.
2.76
d.
2.04
 

 47. 
How many grams of CCl4 are in 4.00 moles?  The formula mass of carbon tetrachloride is 153.8 g/mol.
a.
0.026
c.
2.41 x 1024
b.
615
d.
4.15 x 10-25
 

 48. 
How many grams of ZnCl2 are produced from 75.00 g of ZnO in the reaction
      ZnO +  2HCl ®  ZnCl2 +  H2O ?
a.
44.79
c.
125.6
b.
0.0223
d.
0.00796
 

 49. 
In the equation HCl + KOH ® KCl  +  H2O, how many grams of water are produced if 3.000 moles of HCl are used?
a.
0.166
c.
54.06
b.
6.01
d.
0.0185
 

 50. 
One in a series of reactions that inflates airbags in automobiles is the decomposition of sodium azide (NaN3).
                                    2 NaN3 (s)     ®     2 Na (s)     +     3 N2 (g)
       Determine the mass of N2 produced if 1.00 x 102 g NaN3 is decomposed.
a.
21.5
c.
0.00215
b.
464
d.
64.64
 



 
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