Deck 5: Stoichiometry: Quantitative Information About Chemical Reactions

Question 1

2 Al(s)+ 6 HCl(aq)→ 2 AlCl₃(aq)+ 3 H₂(g) According to the equation above,what mass of aluminum is needed to completely react with 2.98 mol of hydrochloric acid?

A) 241 g
B) 36.3 g
C) 26.8 g
D) 2.98 g
E) 80.4 g

Answer 1

26.8 g

Question 2

Sulfur dioxide will react with water to form sulfurous acid (see balanced equation below). SO₂(g)+ H₂O(l)→ H₂SO₃(l)
What mass of sulfur dioxide is needed to prepare 37.11 g of H₂SO₃(l)?

A) 28.96 g
B) 47.55 g
C) 0.5793 g
D) 0.4521 g
E) 37.11 g

Answer 2

28.96 g

Question 3

If 5.00 g Br₂ and 1.10 g NH₃ react according to the equation below,what is the maximum mass of ammonium bromide produced? 3 Br₂( )+ 8 NH₃(g)→ 6 NH₄Br(s)+ N₂(g)

A) 3.06 g
B) 6.13 g
C) 12.9 g
D) 4.74 g
E) 8.43 g

Answer 3

4.74 g

Question 4

One step in the isolation of pure rhodium metal (Rh)is the precipitation of rhodium(III)hydroxide from a solution containing rhodium(III)sulfate according to the following balanced chemical equation: Rh₂(SO₄)₃(aq)+ 6NaOH(aq)→ 2Rh(OH)₃(s)+ 3Na₂SO₄(aq)
If 3.10 g of rhodium(III)sulfate reacts with excess sodium hydroxide,what mass of rhodium(III)hydroxide may be produced?

A) 1.93 g
B) 6.20 g
C) 3.10 g
D) 0.483 g
E) 3.86 g

Question 5

When strongly heated,boric acid breaks down to boric oxide and water.What mass of boric oxide is formed from the decomposition of 15.0 g of boric acid,B(OH)₃? 2 B(OH)₃(s)→ B₂O₃(s)+ 3 H₂O(g)

A) 7.50 g
B) 15.0 g
C) 8.44 g
D) 16.9 g
E) 33.8 g

Question 6

Nitric oxide is made from the oxidation of ammonia.What mass of nitric oxide can be made from the reaction of 8.00 g NH₃ with 17.0 g O₂? 4 NH₃(g)+ 5 O₂(g)→ 4 NO(g)+ 6 H₂O(g)

A) 4.54 g
B) 12.8 g
C) 14.1 g
D) 15.9 g
E) 25.0 g

Question 7

The complete combustion of 0.31 moles of propane,C₃H₈,will

A) consume 0.31 mol O₂ and produce 0.31 mol CO₂.
B) consume 0.31 mol O₂ and produce 0.62 mol CO₂.
C) consume 1.6 mol O₂ and produce 0.93 mol CO₂.
D) consume 1.6 mol O₂ and produce 4.7 mol CO₂.
E) consume 1.6 mol O₂ and produce 1.2 mol CO₂.

Question 8

Calculate the number of moles of O₂ required to react with phosphorus to produce 5.20 g of P₄O₆.(Molar mass P₄O₆ = 219.9 g/mol)

A) 0.0236 mol
B) 0.163 mol
C) 0.0709 mol
D) 0.0473 mol
E) 0.142 mol

Question 9

If the complete combustion of an unknown mass of ethylene produces 16.0 g CO₂,what mass of ethylene is combusted? C₂H₄(g)+ 3 O₂(g)→ 2 CO₂(g)+ 2 H₂O(g)

A) 0.182 g
B) 0.364 g
C) 5.10 g
D) 8.00 g
E) 12.6 g

Question 10

Pure copper may be produced by the reaction of copper(I)sulfide with oxygen gas as follows: Cu₂S(s)+ O₂(g)→ 2Cu(s)+ SO₂(g)
What mass of copper(I)sulfide is required in order to prepare 0.750 kg of copper metal?

A) 0.750 kg
B) 0.375 kg
C) 0.564 kg
D) 1.88 kg
E) 0.939 kg

Question 11

How many moles of sodium bromide can be produced from the reaction of 1.03 moles of sodium with 0.650 moles of bromine gas? 2 Na(s)+ Br₂(g)→ 2 NaBr(s)

A) 0.650 mol
B) 1.03 mol
C) 1.30 mol
D) 2.06 mol
E) 0.515 mol

Question 12

Magnesium reacts with iodine gas at high temperatures to form magnesium iodide.What mass of magnesium iodide,MgI₂,can be produced from the reaction of 5.15 g Mg and 50.0 g I₂?

A) 29.5 g
B) 44.9 g
C) 54.8 g
D) 55.2 g
E) 58.9 g

Question 13

What mass of iron can be produced from the reaction of 175 kg Fe₂O₃ with 385 kg CO? Fe₂O₃(s)+ 3 CO(g)→ 2 Fe(s)+ 3 CO₂(g)

A) 2.19 kg
B) 30.6 kg
C) 61.2 kg
D) 122 kg
E) 512 kg

Question 14

How many grams of dioxygen are required to completely burn 4.7 g of C₂H₅OH?

A) 11 g
B) 16 g
C) 3.3 g
D) 45 g
E) 57 g

Question 15

The compound P₄S₃ is used in matches.It reacts with oxygen to produce P₄O₁₀ and SO₂.The unbalanced chemical equation is shown below. P₄S₃(s)+ O₂(g)→ P₄O₁₀(s)+ SO₂(g)
What mass of SO₂ is produced from the combustion of 0.401 g P₄S₃?

A) 0.134 g
B) 1.20 g
C) 0.0389 g
D) 0.117 g
E) 0.350 g

Question 16

How many moles of Mg₃P₂(s)can be produced from the reaction of 0.14 mol Mg(s)with 0.020 mol P₄(s)? 6 Mg(s)+ P₄(s)→ 2 Mg₃P₂(s)

A) 0.047 mol
B) 0.14 mol
C) 0.42 mol
D) 0.020 mol
E) 0.040 mol

Question 17

If 56.0 g of O₂ is mixed with 56.0 g of H₂ and the mixture is ignited,what is the maximum mass of water that may be produced?

A) 504 g
B) 63.0 g
C) 56.0 g
D) 112 g
E) 99.6 g

Question 18

Potassium hydrogen carbonate decomposes according to the reaction below: 2 KHCO₃(s)→ K₂CO₃(s)+ CO₂(g)+ H₂O(l)
How many moles of potassium carbonate are produced if 421 g of potassium hydrogen carbonate is heated?

A) 2.10 mol
B) 3.05 mol
C) 17.8 mol
D) 211 mol
E) 4.21 mol

Question 19

Hydrogen peroxide decomposes into oxygen and water.What mass of oxygen is formed from the decomposition of 125 g of hydrogen peroxide (H₂O₂)?

A) 58.8 g
B) 66.4 g
C) 107 g
D) 118 g
E) 125 g

Question 20

Aspirin (C₉H₈O₄)is produced by the reaction of salicylic acid (M = 138.1 g/mol)and acetic anhydride (M = 102.1 g/mol). C₇H₆O₃(s)+ C₄H₆O₃( )→ C₉H₈O₄(s)+ C₂H₄O₂( )
If you react 2.00 g C₇H₆O₃ with 1.60 g C₄H₆O₃,what mass of aspirin (M = 180.2 g/mol)can theoretically be obtained?

A) 0.40 g
B) 2.61 g
C) 2.82 g
D) 1.53 g
E) 3.60 g

Question 21

Nitric oxide,NO,is made from the oxidation of NH₃ as follows: 4NH₃ + 5O₂ → 4NO + 6H₂O If 9.0-g of NH₃ gives 12.0 g of NO,what is the percent yield of NO?

A) 87 %
B) 47 %
C) 13 %
D) 76 %
E) 25 %

Question 22

Consider the fermentation reaction of glucose: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂
A 1)00-mol sample of C₆H₁₂O₆ was placed in a vat with 100 g of yeast.If 38.5 g of C₂H₅OH was obtained,what was the percent yield of C₂H₅OH?

A) 41.8 %
B) 20.9 %
C) 38.5 %
D) 100 %
E) none of these

Question 23

A compound consists of only C and F.It contains 24% C by mass.What is the empirical formula of the compound?

A) CF₂
B) CF₃
C) CF₄
D) C₂F
E) CF

Question 24

A 1.295 g sample of a hydrocarbon is burned in an excess of dioxygen,producing 3.553 g CO₂ and water.What mass of hydrogen is contained in the original sample?

A) 0.3255 g
B) 2.258 g
C) 4.848 g
D) 1.288 g
E) 0.6475 g

Question 25

Of the following,the only empirical formula is

A) C₆H₁₂.
B) C₄H₈.
C) C₃H₁₄.
D) H₂O₂.
E) O₃.

Question 26

The reaction of 11.9 g of CHCl₃ with excess chlorine produced 10.3 g of CCl₄,carbon tetrachloride: 2CHCl₃ + 2Cl₂ → 2CCl₄ + 2HCl
What is the percent yield?

A) 86.6 %
B) 100 %
C) 67.2 %
D) 33.6 %
E) 44.8 %

Question 27

Pure copper may be produced by the reaction of copper(I)sulfide with oxygen gas as follows: Cu₂S(s)+ O₂(g)→ 2Cu(s)+ SO₂(g)
If the reaction of 0.760 kg of copper(I)sulfide with excess oxygen produces 0.310 kg of copper metal,what is the percent yield?

A) 102 %
B) 39.9 %
C) 40.8 %
D) 204 %
E) 51.1 %

Question 28

The empirical formula of styrene is CH.An experimental determination of the molar mass of styrene yields the value of 104 g/mol.What is the molecular formula of styrene?

A) C₅H₁₀
B) C₂
C) C₈H₈
D) C₃H₈
E) C₆H₉

Question 29

Sulfur trioxide (SO₃)is produced from the oxidation of SO₂ as follows: 2 SO₂ + O₂ → 2 SO₃ A 23-g sample of SO₂ gives 18 g of SO₃.Calculate the percent yield of sulfur trioxide,SO₃.

A) 10 %
B) 63 %
C) 15 %
D) 29 %
E) 100 %

Question 30

A 2.288 g sample of a hydrocarbon is burned in an excess of dioxygen,producing 6.277 g CO₂ and 5.139 g H₂O.What is the empirical formula of the hydrocarbon?

A) CH₄
B) CH₂
C) C₂H₃
D) CH₃
E) CH

Question 31

If 15.0 g of nitrogen (N₂)and 2.00 g of hydrogen (H₂)react to produce 1.38 g of ammonia (NH₃),according to the reaction below,what is the percent yield of the reaction? N₂(g)+ 3 H₂(g)→ 2 NH₃(g)

A) 7.57%
B) 12.2%
C) 8.12%
D) 15.1%
E) 8.17%

Question 32

A 5.95-g sample of AgNO₃ is reacted with excess BaCl₂ according to the equation 2AgNO₃(aq)+ BaCl₂(aq)→ 2AgCl(s)+ Ba(NO₃)₂(aq)
To give 3.57 g of AgCl.What is the percent yield of AgCl?

A) 47.4 %
B) 35.6 %
C) 71.1 %
D) 60.0 %
E) 100 %

Question 33

Sulfur hexafluoride is produced by reacting elemental sulfur with fluorine gas. S₈(s)+ 24 F₂(g)→ 8 SF₆(g)
What is the percent yield if 18.3 g SF₆ is isolated from the reaction of 10.0 g S₈ and 30.0 g F₂?

A) 40.2%
B) 45.8%
C) 47.6%
D) 54.6%
E) 61.0%

Question 34

The reaction of 0.779 g K with O₂ forms 1.417 g potassium superoxide,a substance used in self-contained breathing devices.Determine the formula for potassium superoxide.

A) KO₂
B) KO
C) K₂O₃
D) K₂O
E) KO₄

Question 35

Chlorine was passed over 1.06 g of heated titanium,and 3.40 g of a chloride-containing compound of titanium was obtained.What is the empirical formula of the obtained compound?

A) TiCl₂
B) TiCl₄
C) TiCl
D) TiCl₃
E) Ti₂Cl₃

Question 36

A 1.850 g mixture of SrCO₃ and SrO is heated.The SrCO₃ decomposes to SrO and CO₂.What was the mass percentage of SrCO₃ in the mixture if the mass after heating is 1.445 g?

A) 26.6%
B) 21.9%
C) 13.7%
D) 73.4%
E) 78.1%

Question 37

Under certain conditions the reaction of ammonia with excess oxygen will produce a 29.5% yield of NO.What mass of NH₃ must react with excess oxygen to yield 157 g NO? 4 NH₃(g)+ 5 O₂(g)→ 4 NO(g)+ 6 H₂O(g)

A) 89.1 g
B) 302 g
C) 263 g
D) 26.3 g
E) 938 g

Question 38

Aspirin is produced by the reaction of salicylic acid (M = 138.1 g/mol)and acetic anhydride (M = 102.1 g/mol). C₇H₆O₃(s)+ C₄H₆O₃( )→ C₉H₈O₄(s)+ C₂H₄O₂( )
If 2.04 g of C₉H₈O₄ (M = 180.2 g/mol)is produced from the reaction of 3.03 g C₇H₆O₃ and 4.01 g C₄H₆O₃,what is the percent yield?

A) 28.8%
B) 29.0%
C) 50.9%
D) 51.6%
E) 67.3%

Question 39

A certain compound has a molar mass of 210 g/mol.Which of the following is a possible empirical formula for this compound?

A) CH₂O
B) CHO
C) C₂H₂O₂
D) C₂HO
E) C₂H₂O

Question 40

Complete combustion of a 0.70-mol sample of a hydrocarbon,C_xH_y,gives 2.80 mol of CO₂ and 3.50 mol of H₂O.The molecular formula of the original hydrocarbon is

A) C₂H₈.
B) C₄H₁₀.
C) C₈H₁₄.
D) C₅H₅.
E) C₄H₆.

Question 41

What is the molarity of an NaI solution that contains 4.5 g of NaI in 21.0 mL of solution?

A) 1.4 M
B) 0.030 M
C) 0.0047 M
D) 0.00014 M
E) 0.21 M

Question 42

What is the pH of 4.1 × 10−³ M HCl(aq)?

A) -1.01
B) 2.39
C) 3.50
D) 1.01
E) 5.65

Question 43

A 1.078 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 2.451 g CO₂ and 1.003 g H₂O.What mass of oxygen is contained in the original sample?

A) 0.2970 g
B) 0.3531 g
C) 1.373 g
D) 1.447 g
E) 0.07480 g

Question 44

A mass of 0.4113 g of an unknown acid,HA,is titrated with sodium hydroxide,NaOH.If the acid reacts with 28.10 mL of 0.1055 M aqueous sodium hydroxide,what is the molar mass of the acid?

A) 2.965 × 10^-3 g/mol
B) 9.128 g/mol
C) 138.7 g/mol
D) 337.3 g/mol
E) 820.7 g/mol

Question 45

The combustion of 0.0272 mole of a hydrocarbon produces 1.9609 g H₂O and 3.5927 g CO₂.What is the molar mass of the hydrocarbon?

A) 16.0 g/mol
B) 30.1 g/mol
C) 44.1 g/mol
D) 72.2 g/mol
E) 92.1 g/mol

Question 46

A dilute solution is prepared by transferring 35.00 mL of a 0.6363 M stock solution to a 900.0 mL volumetric flask and diluting to mark.What is the molarity of this dilute solution?

A) 0.02474 M
B) 0.04949 M
C) 0.1636 M
D) 0.006186 M
E) 0.3182 M

Question 47

Zn reacts with hydrochloric acid. Zn(s)+ 2 HCl(aq)→ ZnCl₂(aq)+ H₂(g)
What volume of 3.05 M HCl(aq)will react with 25.0 g Zn(s)?

A) 0.251 L
B) 4.01 L
C) 0.125 L
D) 0.0627 L
E) 2.33 L

Question 48

In order to dilute 77.1 mL of 0.778 M HCl to 0.100 M,the volume of water that must be added is

A) 67.2 mL.
B) 9.91 mL.
C) 6 × 10² mL.
D) 1.01 × 10^-3 mL.
E) 5.23 × 10² mL.

Question 49

How many moles of sulfate ions are there in a 0.650-L solution of 0.312 M Al₂(SO₄)₃?

A) 0.203 mol
B) 0.608 mol
C) 6.25 mol
D) 0.0676 mol
E) 1.44 mol

Question 50

The pH of an aqueous sodium hydroxide solution is 12.83.What is the hydronium ion concentration of this solution?

A) 1.5 × 10^-13 M
B) 6.7 × 10^-2 M
C) 1.2 M
D) 6.7 × 10¹² M
E) 2.7 × 10^-6 M

Question 51

A 2.197 g sample of a compound containing only carbon,hydrogen,and oxygen is burned in an excess of dioxygen,producing 4.197 g CO₂ and 2.578 g H₂O.What is the empirical formula of the compound?

A) CHO
B) C₂H₆O
C) C₃H₆O
D) C₃H₄O
E) C₃H₈O₃

Question 52

Naphthalene,a hydrocarbon,has an approximate molar mass of 128 g/mole.If the combustion of 0.6400 g of naphthalene produces 0.3599 g of H₂O and 2.1977 g of CO₂,what is the molecular formula of this compound?

A) C₈H₃₂
B) C₉H₁₈
C) C₉H₂₀
D) C₁₀H₈
E) C₁₁H₇

Question 53

What volume of 1.27 M HCl is required to prepare 197.4 mL of 0.456 M HCl?

A) 5.5 × 10² mL
B) 3.41 × 10² mL
C) 70.9 mL
D) 0.0141 mL
E) 1.14 × 10² mL

Question 54

Soft drink bottles are made of polyethylene terephthalate (PET),a polymer composed of carbon,hydrogen,and oxygen.If 1.9022 g PET is burned in oxygen it produces 0.6585 g H₂O and 4.0216 g CO₂.What is the empirical formula of PET?

A) CHO
B) CH₇O₅
C) C₅H₇O
D) C₈H₁₀O
E) C₁₀H₈O₅

Question 55

The pH of a vinegar solution is 4.15.What is the H₃O⁺ concentration of the solution?

A) 7.1 × 10^-5 M
B) 1.6 × 10^-2 M
C) 0.62 M
D) 1.4 M
E) 1.4 × 10⁴ M

Question 56

An aqueous nitric acid solution has a pH of 2.15.What mass of nitric acid,HNO₃,is present in 20.0 L of this solution?

A) 0.11 g
B) 0.022 g
C) 3.7 g
D) 6.8 g
E) 8.9 g

Question 57

What mass of Na₂CO₃ is present in 0.700 L of a 0.396 M Na₂CO₃ solution?

A) 29.4 g
B) 74.2 g
C) 42.0 g
D) 187 g
E) 60.0 g

Question 58

What minimum mass of cobalt (II)nitrate must be added to 60.0 mL of a 0.0999 M phosphate solution in order to completely precipitate all of the phosphate as solid cobalt (II)phosphate? 2PO₄^3-(aq)+ 3Co(NO₃)₂(aq)→ Co₃(PO₄)₂(s)+ 6NO₃^-(aq)

A) 1.10 g
B) 3.29 g
C) 0.731 g
D) 0.366 g
E) 1.64 g

Question 59

Polyethylene is a polymer consisting of only carbon and hydrogen.If 2.300 g of the polymer is burned in oxygen it produces 2.955 g of H₂O and 7.217 g of CO₂.Determine the empirical formula of polyethylene.

A) CH
B) CH₂
C) C₂H₃
D) C₅H₈
E) C₇H₈

Question 60

What volume of 0.742 M Na₂CO₃ solution contains 44.9 g of Na₂CO₃?

A) 0.314 L
B) 6.41 × 10³ L
C) 0.571 L
D) 3.53 × 10³ L
E) 1.75 L

Question 61

Which of the following is true about the actual yield of a product?

A) It is almost always less than the theoretical yield.
B) It is always equal to the theoretical yield of the reaction.
C) It is always greater than the theoretical yield.
D) It is obtained from a stoichiometry calculation.
E) It is equal to the molar mass of the product.

Question 62

The reaction of 5.07 g N₂ with 0.722 g H₂ produces 1.27 g NH₃.The percent yield of this reaction is ________.

Question 63

Phosphorus trichloride,PCl₃,can be produced from the reaction below:
P₄(s)+ 6 Cl₂(g)→ 4 PCl₃(g)
If 1.00 g of phosphorus,P₄,reacts with 1.00 g of chlorine,Cl₂,which reactant is the limiting reactant and what mass of product may be produced?

Question 64

In combustion analysis,the gases produced by the combustion of a hydrocarbon are passed through a tube containing finely divided sodium hydroxide supported on asbestos.The purpose of the sodium hydroxide is to absorb ________ produced by the combustion reaction.

Question 65

The following equation: A = ε × × C (where is path length and C is concentration)is known as the _____-Lambert law.

Question 66

The percent yield of a chemical reaction is calculated by dividing the actual yield by the ________ yield and multiplying by 100%.

Question 67

The pH of purified water (or of a neutral solution)is _____.

Question 68

Calibration of a spectrophotometer using a series of green dye containing solutions provides a set of data which follows the Beer-Lambert Law,with a trendline of y = 1.398 × 10³x (y-axis = absorbance,x-axis = molar concentration).What is the molar concentration of a solution with an absorbance of 0.8427?

A) 0.6028 M
B) 0.8427 M
C) 1.187 M
D) 0.7153 M
E) 0.1573

Question 69

A solution of sodium oxalate (Na₂C₂O₄)in acidic solution is titrated with a solution of potassium permanganate (KMnO₄)according to the following balanced chemical equation: 2KMnO₄(aq)+ 8H₂SO₄(aq)+ 5Na₂C₂O₄(aq)→ 2MnSO₄(aq)+ 8H₂O(l)+ 10CO₂(g)+ 5Na₂SO₄(aq)+ K₂SO₄(aq)
What volume of 0.0206 M KMnO₄ is required to titrate 0.176 g of Na₂C₂O₄ dissolved in 50.0 mL of solution?

A) 3.42 mL
B) 8.54 mL
C) 25.5 mL
D) 63.8 mL
E) 50.0 mL

Question 70

The reaction of HCl with NaOH is represented by the equation HCl(aq)+ NaOH(aq)→ NaCl(aq)+ H₂O(l)
What volume of 0.614 M HCl is required to titrate 18.8 mL of 0.619 M NaOH?

A) 7.15 mL
B) 1.63 mL
C) 19.0 mL
D) 18.8 mL
E) 18.6 mL

Question 71

The numbers preceding the formulas in chemical equations are referred to as the _____ coefficients.

Question 72

An unknown diprotic acid (H₂A)requires 31.81 mL of 0.109 M NaOH to completely neutralize a 0.685 g sample.Calculate the approximate molar mass of the acid.

A) 577 g/mol
B) 395 g/mol
C) 198 g/mol
D) 99 g/mol
E) 288 g/mol

Question 73

Molarity is defined as the _____.

A) number of mole equivalents per liter of solution
B) amount of solute per liter of solution
C) mass of a constituent divided by the volume of the mixture
D) ratio of one substance with the mass of the total mixture
E) amount of a constituent divided by the total amount of all constituents in a mixture

Question 74

If 0.1800 g of impure soda ash (Na₂CO₃)is titrated with 15.66 mL of 0.1082 M HCl,what is the percent purity of the soda ash? Na₂CO₃(aq)+ 2 HCl(aq)→ 2 NaCl(aq)+ H₂O( )+ CO₂(g)

A) 17.96%
B) 49.89%
C) 50.11%
D) 94.13%
E) 99.77%

Question 75

A 30.00-mL sample of a weak monoprotic acid is titrated with 0.0915 M NaOH.At the endpoint,it is found that 45.98 mL of titrant was used.What was the concentration of the weak acid?

A) 0.140 M
B) 4.21 M
C) 0.0915 M
D) 6.63 × 10^-5 M
E) 0.0597 M

Question 76

An impure sample of benzoic acid (C₆H₅COOH,122.12 g/mol)is titrated with 0.5360 M NaOH.A 1.888-g sample requires 20.50 mL of titrant to reach the endpoint.What is the percent by mass of benzoic acid in the sample? C₆H₅COOH(aq)+ NaOH(aq)→ NaC₆H₅COO(aq)+ H₂O(l)

A) 0.008998 %
B) 1.099 %
C) 100.0 %
D) 8.998 %
E) 71.06 %

Question 77

Which of the following is the correct representation for absorbance of a sample?

A) A = -log T
B) A = log (-T)
C) A = 10^T
D) A = 10^-T
E) A = 10^-1/T