Question 1

Balance the equation B2O3(s) + NaOH(aq) $\rightarrow$Na3BO3(aq) + H2O(l)

Accepted Answer

B₂O₃(s) + 6N...

Question 2

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. 
N2(g)  + 3H2(g)   →\rightarrow→  2NH3(g) 
How many grams of nitrogen are needed to produce 325 grams of ammonia?

Accepted Answer

A)   1070 g
B)   535 g
C)   267 g
D)   178 g
E)   108 g F) A) and C)
G) B) and E)

Question 3

Hydrochloric acid is widely used as a laboratory reagent in refining ore for the production of tin and tantalum, and as a catalyst in organic reactions. Calculate the number of moles of HCl in 62.85 mL of 0.453 M hydrochloric acid.

Accepted Answer

A)   28.5 mol
B)   1.04 mol
C)   0.139 mol
D)   0.0285 mol
E)   0.00721 molF) None of the above
G) C) and D)

Question 4

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Accepted Answer

A)   Gd2O3
B)   Gd3O2
C)   Gd3O4
D)   Gd4O3
E)   GdOF) A) and B)
G) B) and E)

Question 5

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Accepted Answer

A)   HNO
B)   H2NO2
C)   HN6O16
D)   HN16O7
E)   H2NO3F) None of the above
G) All of the above

Question 6

Aluminum will react with bromine to form aluminum bromide (used as an acid catalyst in organic synthesis) . 
Al(s)  + Br2(l)   →\rightarrow→ Al2Br6(s)  [unbalanced]
How many moles of Al are needed to form 2.43 mol of Al2Br6?

Accepted Answer

A)   7.29 mol
B)   4.86 mol
C)   2.43 mol
D)   1.62 mol
E)   1.22 mol F) A) and B)
G) C) and D)

Question 7

Aluminum oxide, Al2O3, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al2O3.

Accepted Answer

A)   2.377 mol
B)   2.146 mol
C)   1.105 mol
D)   0.4660 mol
E)   0.4207 molF) A) and E)
G) B) and E)

Question 8

One mole of methane (CH4) contains a total of 3 * 1024 atoms.

Accepted Answer

A) True 
 B)False

Question 9

A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula.

Accepted Answer

A)   CrSi3
B)   Cr2Si3
C)   Cr3Si
D)   Cr3Si2
E)   Cr2SF) C) and D)
G) A) and B)

Question 10

The iodine "clock reaction" involves the following sequence of reactions occurring in a reaction mixture in a single beaker. 
1. IO3¯(aq)  + 5I¯(aq)  + 6H+(aq)   →\rightarrow→ 3I2(aq)  + 3H2O(l) 
2. I2(aq)  + 2S2O32¯(aq)   →\rightarrow→  2I¯(aq)  + S4O62¯(aq) 
The molecular iodine (I2)  formed in reaction 1 is immediately used up in reaction 2, so that no iodine accumulates. What is the overall reaction occurring in this experiment?

Accepted Answer

A)   IO3¯(aq)  + 3I¯(aq)  + 2S2O32¯(aq)  + 6H+(aq)   →\rightarrow→  2I2(aq)  + S4O62¯(aq)  + 3H2O(l) 
B)   IO3¯(aq)  + 4S2O32¯(aq)  + 6H+(aq)   →\rightarrow→  I¯(aq)  + 2S4O62¯(aq)  + 3H2O(l) 
C)   IO3¯(aq)  + 6S2O32¯(aq)  + 6H+(aq)   →\rightarrow→  I¯(aq)  + 3S4O62¯(aq)  + 3H2O(l) 
D)   IO3¯(aq)  + I2(aq)  + 8S2O32¯(aq)  + 6H+(aq)   →\rightarrow→  3I¯(aq)  + 4S4O62¯(aq)  + 3H2O(l) 
E)   IO3¯(aq)  + 2I2(aq)  + 6S2O32¯(aq)  + 6H+(aq)   →\rightarrow→  5I¯(aq)  + 3S4O62¯(aq)  + 3H2O(l)  F) C) and E)
G) B) and D)

Question 11

Calculate the molarity of a 23.55-mL solution which contains 28.24 mg of sodium sulfate (used in dyeing and printing textiles, м = 139.04 g/mol) .

Accepted Answer

A)   8.625 M
B)   1.199 M
C)   0.8339 M
D)   0.2031 M
E)   0.008625 MF) B) and C)
G) C) and E)

Question 12

Sodium chlorate is used as an oxidizer in the manufacture of dyes, explosives and matches. Calculate the mass of solute needed to prepare 1.575 L of 0.00250 M NaClO3 (м = 106.45 g/mol) .

Accepted Answer

A)   419 g
B)   169 g
C)   0.419 g
D)   0.169 g
E)   0.00394 gF) All of the above
G) A) and C)

Question 13

Aqueous potassium iodate (KIO3)  and potassium iodide (KI)  react in the presence of dilute hydrochloric acid (HCl) , as shown below. 
KIO3(aq)  + 5KI(aq)  + 6HCl(aq)   →\rightarrow→  3I2(aq)  + 6KCl(aq)  + 3H2O(l) 
What mass of iodine (I2)  is formed when 15.0 mL of 0.0050 M KIO3 solution reacts with 30.0 mL of 0.010 M KI solution in the presence of excess HCl?

Accepted Answer

A)   0.023 g I2
B)   0.029 g I2
C)   0.057 g I2
D)   0.046 g I2
E)   0.076 g I2 F) B) and C)
G) All of the above

Question 14

Which of the following samples contains the greatest total number atoms?

Accepted Answer

A)   50.0 g of Li2O
B)   75.0 g of CaO
C)   200.0 g of Fe2O3
D)   50.0 g of CO2
E)   100.0 g of SO3F) None of the above
G) A) and B)

Question 15

Consider the balanced equation for the combustion of propane, C3H8
C3H8(g) + 5O2(g) $\rightarrow$3CO2(g) + 4H2O(l)
If propane reacts with oxygen as above
A) what is the limiting reagent in a mixture containing 5.00 g of C3H8 and 10.0 g of O2?
B) what mass of CO2 is formed when 1.00 g of C3H8 reacts completely?

Accepted Answer

a. Oxygen ...

Question 16

Balance the following equation: 
Ca3(PO4) 2(s)  + SiO2(s)  + C(s)   →\rightarrow→  CaSiO3(s)  + CO(g)  + P4(s)

Accepted Answer

A)   Ca3(PO4) 2(s)  + 3SiO2(s)  + 8C(s)   →\rightarrow→  3CaSiO3(s)  + 8CO(g)  + P4(s) 
B)   Ca3(PO4) 2(s)  + 3SiO2(s)  + 14C(s)   →\rightarrow→  3CaSiO3(s)  + 14CO(g)  + P4(s) 
C)   Ca3(PO4) 2(s)  + 3SiO2(s)  + 8C(s)   →\rightarrow→  3CaSiO3(s)  + 8CO(g)  + 2P4(s) 
D)   2Ca3(PO4) 2(s)  + 6SiO2(s)  + 10C(s)   →\rightarrow→ 6CaSiO3(s)  + 10CO(g)  + P4(s) 
E)   2Ca3(PO4) 2(s)  + 6SiO2(s)  + 10C(s)   →\rightarrow→  6CaSiO3(s)  + 10CO(g)  + 4P4(s)  F) B) and C)
G) A) and E)

Question 17

Copper(II)  sulfate pentahydrate, CuSO4·5H2O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO4·5H2O.

Accepted Answer

A)   249.7 g
B)   144.0 g
C)   96.00 g
D)   80.00 g
E)   64.00 gF) C) and D)
G) A) and B)

Question 18

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Accepted Answer

A)   BrF
B)   BrF2
C)   Br2F3
D)   Br3F
E)   BrF3F) C) and E)
G) None of the above

Question 19

In a blast furnace, elemental iron is produced from a mixture of coke (C) , iron ore (Fe3O4)  and other reactants. An important reaction sequence is: 
2C(s)  + O2(g)   →\rightarrow→ 2CO(g) 
Fe3O4(s)  + 4CO(g)   →\rightarrow→  3Fe(l)  + 4CO2(g) 
How many moles of iron can be formed in this sequence when 1.00 mol of carbon, as coke, is consumed?

Accepted Answer

A)   6.00 mol Fe
B)   3.00 mol Fe
C)   1.33 mol Fe
D)   1.25 mol Fe
E)   0.750 mol Fe F) B) and E)
G) None of the above

Question 20

Potassium chlorate (used in fireworks, flares and safety matches)  forms oxygen and potassium chloride when heated. KClO3(s)   →\rightarrow→  KCl(s)  + O2(g)  [unbalanced]
How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Accepted Answer

A)   223 g
B)   99.1 g
C)   10.3 g
D)   6.86 g
E)   4.60 g F) C) and D)
G) B) and E)

Exam 3: Stoichiometry of Formulas and Equations

A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula.

Correct Answer
verified

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Correct Answer
verified

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Correct Answer
verified

Sodium chlorate is used as an oxidizer in the manufacture of dyes, explosives and matches. Calculate the mass of solute needed to prepare 1.575 L of 0.00250 M NaClO₃ (м = 106.45 g/mol) .

Correct Answer
verified

Calculate the molarity of a 23.55-mL solution which contains 28.24 mg of sodium sulfate (used in dyeing and printing textiles, м = 139.04 g/mol) .

Correct Answer
verified

Aluminum oxide, Al₂O₃, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al₂O₃.

Correct Answer
verified

Balance the following equation: Ca₃(PO₄) ₂(s) + SiO₂(s) + C(s) $\rightarrow$ CaSiO₃(s) + CO(g) + P₄(s)

Correct Answer
verified

Copper(II) sulfate pentahydrate, CuSO₄·5H₂O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO₄·5H₂O.

Correct Answer
verified

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g) How many grams of nitrogen are needed to produce 325 grams of ammonia?

Correct Answer
verified

Aluminum will react with bromine to form aluminum bromide (used as an acid catalyst in organic synthesis) . Al(s) + Br₂(l) $\rightarrow$ Al₂Br₆(s) [unbalanced] How many moles of Al are needed to form 2.43 mol of Al₂Br₆?

Correct Answer
verified

Potassium chlorate (used in fireworks, flares and safety matches) forms oxygen and potassium chloride when heated. KClO₃(s) $\rightarrow$ KCl(s) + O₂(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct Answer
verified

Hydrochloric acid is widely used as a laboratory reagent in refining ore for the production of tin and tantalum, and as a catalyst in organic reactions. Calculate the number of moles of HCl in 62.85 mL of 0.453 M hydrochloric acid.

Correct Answer
verified

One mole of methane (CH₄) contains a total of 3 * 10²⁴ atoms.

Correct Answer
verified

Correct Answer
verified

A compound of bromine and fluorine is used to make UF₆, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct Answer
verified

Which of the following samples contains the greatest total number atoms?

Correct Answer
verified

Correct Answer
verified

Balance the equation B₂O₃(s) + NaOH(aq) $\rightarrow$ Na₃BO₃(aq) + H₂O(l)

Correct Answer
verified
B₂O₃(s) + 6N...
View Answer

Correct Answer
verified

Correct Answer
verified
a. Oxygen ...
View Answer

Exam 3: Stoichiometry of Formulas and Equations

A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Sodium chlorate is used as an oxidizer in the manufacture of dyes, explosives and matches. Calculate the mass of solute needed to prepare 1.575 L of 0.00250 M NaClO3 (м = 106.45 g/mol) .

Correct AnswerverifiedShow Answer

Calculate the molarity of a 23.55-mL solution which contains 28.24 mg of sodium sulfate (used in dyeing and printing textiles, м = 139.04 g/mol) .

Correct AnswerverifiedShow Answer

Aluminum oxide, Al2O3, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al2O3.

Correct AnswerverifiedShow Answer

Balance the following equation: Ca3(PO4) 2(s) + SiO2(s) + C(s) →\rightarrow→ CaSiO3(s) + CO(g) + P4(s)

Correct AnswerverifiedShow Answer

Copper(II) sulfate pentahydrate, CuSO4·5H2O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO4·5H2O.

Correct AnswerverifiedShow Answer

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N2(g) + 3H2(g) →\rightarrow→ 2NH3(g) How many grams of nitrogen are needed to produce 325 grams of ammonia?

Correct AnswerverifiedShow Answer

Aluminum will react with bromine to form aluminum bromide (used as an acid catalyst in organic synthesis) . Al(s) + Br2(l) →\rightarrow→ Al2Br6(s) [unbalanced] How many moles of Al are needed to form 2.43 mol of Al2Br6?

Correct AnswerverifiedShow Answer

Potassium chlorate (used in fireworks, flares and safety matches) forms oxygen and potassium chloride when heated. KClO3(s) →\rightarrow→ KCl(s) + O2(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct AnswerverifiedShow Answer

Hydrochloric acid is widely used as a laboratory reagent in refining ore for the production of tin and tantalum, and as a catalyst in organic reactions. Calculate the number of moles of HCl in 62.85 mL of 0.453 M hydrochloric acid.

Correct AnswerverifiedShow Answer

One mole of methane (CH4) contains a total of 3 * 1024 atoms.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Which of the following samples contains the greatest total number atoms?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Balance the equation B2O3(s) + NaOH(aq) →\rightarrow→ Na3BO3(aq) + H2O(l)

Correct AnswerverifiedB2O3(s) + 6N...View AnswerShow Answer

Correct AnswerverifiedShow Answer

Correct Answerverifieda. Oxygen ...View AnswerShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Sodium chlorate is used as an oxidizer in the manufacture of dyes, explosives and matches. Calculate the mass of solute needed to prepare 1.575 L of 0.00250 M NaClO₃ (м = 106.45 g/mol) .

Correct Answer
verified

Correct Answer
verified

Aluminum oxide, Al₂O₃, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al₂O₃.

Correct Answer
verified

Balance the following equation: Ca₃(PO₄) ₂(s) + SiO₂(s) + C(s) $\rightarrow$ CaSiO₃(s) + CO(g) + P₄(s)

Correct Answer
verified

Copper(II) sulfate pentahydrate, CuSO₄·5H₂O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO₄·5H₂O.

Correct Answer
verified

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g) How many grams of nitrogen are needed to produce 325 grams of ammonia?

Correct Answer
verified

Aluminum will react with bromine to form aluminum bromide (used as an acid catalyst in organic synthesis) . Al(s) + Br₂(l) $\rightarrow$ Al₂Br₆(s) [unbalanced] How many moles of Al are needed to form 2.43 mol of Al₂Br₆?

Correct Answer
verified

Potassium chlorate (used in fireworks, flares and safety matches) forms oxygen and potassium chloride when heated. KClO₃(s) $\rightarrow$ KCl(s) + O₂(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct Answer
verified

Correct Answer
verified

One mole of methane (CH₄) contains a total of 3 * 10²⁴ atoms.

Correct Answer
verified

Correct Answer
verified

A compound of bromine and fluorine is used to make UF₆, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Balance the equation B₂O₃(s) + NaOH(aq) $\rightarrow$ Na₃BO₃(aq) + H₂O(l)

Correct Answer
verified
B₂O₃(s) + 6N...
View Answer

Correct Answer
verified

Correct Answer
verified
a. Oxygen ...
View Answer