Deck 3: Stoichiometry of Formulas and Equations

Question 1

Which of the following samples has the most moles of the compound?

A)50.0 g of Li ₂O
B)75.0 g of CaO
C)200.0 g of Fe ₂O ₃
D)50.0 g of CO ₂
E)100.0 g of SO ₃

Answer 1

50.0 g of Li ₂O

Question 2

The formula CH₃O_0.5 is an example of an empirical formula.

Answer 2

False

Question 3

Sodium bromate is used in a mixture which dissolves gold from its ores. Calculate the mass in grams of 4.68 mol of sodium bromate.

A)706 g
B)482 g
C)383 g
D)32.2 g
E)0.0310 g

Answer 3

706 g

Question 4

Calculate the molar mass of tetraphosphorus decaoxide, P₄O₁₀, a corrosive substance which can be used as a drying agent.

A)469.73 g/mol
B)283.89 g/mol
C)190.97 g/mol
D)139.88 g/mol
E)94.97 g/mol

Question 5

Calculate the molar mass of (NH₄)₃AsO₄.

A)417.80 g/mol
B)193.03 g/mol
C)165.02 g/mol
D)156.96 g/mol
E)108.96 g/mol

Question 6

Calculate the molar mass of rubidium carbonate, Rb₂CO₃.

A)340.43 g/mol
B)255.00 g/mol
C)230.94 g/mol
D)145.47 g/mol
E)113.48 g/mol

Question 7

Aluminum sulfate, Al₂(SO₄)₃, is used in tanning leather, purifying water, and manufacture of antiperspirants. Calculate its molar mass.

A)450.06 g/mol
B)342.15 g/mol
C)315.15 g/mol
D)278.02 g/mol
E)74.98 g/mol

Question 8

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

Question 9

Calculate the molar mass of Ca(BO₂)₂·6H₂O.

A)273.87 g/mol
B)233.79 g/mol
C)183.79 g/mol
D)174.89 g/mol
E)143.71 g/mol

Question 10

Constitutional (structural) isomers have the same molecular formula but different structural formulas.

Question 11

Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

A)43.3 g
B)62.3 g
C)74.5 g
D)92.9 g
E)107 g

Question 12

Calculate the number of moles in 17.8 g of the antacid magnesium hydroxide, Mg(OH)₂.

A)3.28 mol
B)2.32 mol
C)0.431 mol
D)0.305 mol
E)0.200 mol

Question 13

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO₂ and H₂O, respectively, which are collected in the absorbers.

Question 14

Constitutional (structural) isomers have the same empirical formula but different molecular formulas.

Question 15

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.

A)118.15 g/mol
B)99.15 g/mol
C)78.07 g/mol
D)59.08 g/mol
E)50.01 g/mol

Question 16

Phosphorus pentachloride, PCl₅, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl₅.

A)5.38 mol
B)3.55 mol
C)0.583 mol
D)0.282 mol
E)0.186 mol

Question 17

What is the mass in grams of 0.250 mol of the common antacid calcium carbonate?

A)4.00 × 10 ² g
B)25.0 g
C)17.0 g
D)4.00 × 10 ⁻² g
E)2.50 × 10 ⁻³ g

Question 18

Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na₂SO₄.

A)1.244 × 10 ²³ O atoms
B)4.976 × 10 ²³ O atoms
C)2.409 × 10 ²⁴ O atoms
D)2.915 × 10 ²⁴ O atoms
E)1.166 × 10 ²⁵ O atoms

Question 19

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.

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

Question 20

In combustion analysis, the oxygen content of a substance is equal to the total oxygen in the CO₂ and H₂O collected in the absorbers.

Question 21

Analysis of a carbohydrate showed that it consisted of 40.0 % C, 6.71 % H, and 53.3 % O by mass. Its molecular mass was found to be between 140 and 160 amu. What is the molecular formula of this compound?

A)C ₄H ₈O ₆
B)C ₅H ₁₀O ₅
C)C ₅H ₁₂O ₅
D)C ₆H ₁₂O ₄
E)None of these choices are correct.

Question 22

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

A)Gd ₂O ₃
B)Gd ₃O ₂
C)Gd ₃O ₄
D)Gd ₄O ₃
E)GdO

Question 23

Household sugar, sucrose, has the molecular formula C₁₂H₂₂O₁₁. What is the percent of carbon in sucrose, by mass?

A)26.7%
B)33.3%
C)41.4%
D)42.1%
E)52.8%

Question 24

Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO₃)₂.

A)107 g
B)90.8 g
C)87.0 g
D)83.4 g
E)62.6 g

Question 25

Determine the percent composition of potassium dichromate, K₂Cr₂O₇.

A)17.5% K, 46.6% Cr, 35.9% O
B)29.8% K, 39.7% Cr, 30.5% O
C)36.5% K, 48.6% Cr, 14.9% O
D)37.2% K, 24.7% Cr, 38.1% O
E)None of these choices are correct.

Question 26

The number of hydrogen atoms in 0.050 mol of C₃H₈O₃ is

A)3.0 × 10 ²² H atoms.
B)1.2 × 10 ²³ H atoms.
C)2.4 × 10 ²³ H atoms.
D)4.8 × 10 ²³ H atoms.
E)None of these choices are correct.

Question 27

Calculate the mass in grams of 8.35 × 10²² molecules of CBr₄.

A)0.0217 g
B)0.139 g
C)7.21 g
D)12.7 g
E)46.0 g

Question 28

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

A)CrSi ₃
B)Cr ₂Si ₃
C)Cr ₃Si
D)Cr ₃Si ₂
E)Cr ₂S

Question 29

A normal breath takes in about 1.0 L of air. Assuming that air has an average molar mass of 28.8 g, and that its density is 0.97 g/L, how many molecules of air do you take in with each breath?

A)2.0 × 10 ²²
B)2.2 × 10 ²²
C)5.8 × 10 ²³
D)1.7 × 10 ²⁵
E)1.8 × 10 ²⁵

Question 30

How many atoms are in a drop of mercury that has a diameter of 1.0 mm? (Volume of a sphere is 4πr³/3; density of mercury = 13.6 g/cm³)

A)2.1 × 10 ¹⁹
B)1.7 × 10 ²⁰
C)2.1 × 10 ²²
D)1.7 × 10 ²³
E)None of these choices are correct.

Question 31

Sulfur trioxide can react with atmospheric water vapor to form sulfuric acid that falls as acid rain. Calculate the mass in grams of 3.65 × 10²⁰ molecules of SO₃.

A)6.06 × 10 ⁻⁴ g
B)2.91 × 10 ⁻² g
C)4.85 × 10 ⁻² g
D)20.6 g
E)1650 g

Question 32

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.

A)BrF
B)BrF ₂
C)Br ₂F ₃
D)Br ₃F
E)BrF ₃

Question 33

Potassium dichromate, K₂Cr₂O₇, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K₂Cr₂O₇.

A)9.490 × 10 ²⁵ Cr atoms
B)2.248 × 10 ²⁴ Cr atoms
C)1.124 × 10 ²⁴ Cr atoms
D)3.227 × 10 ²³ Cr atoms
E)1.613 × 10 ²³ Cr atoms

Question 34

How many protons are there in a molecule of adrenaline (C₉H₁₃NO₃), a neurotransmitter and hormone?

A)22
B)26
C)43
D)98
E)183

Question 35

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.

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

Question 36

A single atom of hydrogen has a mass of 1.0 amu, while a mole of hydrogen atoms has a mass of 1.0 g. Select the correct conversion factor between atomic mass units and grams.

A)1 amu = 1 g exactly
B)1 amu = 6.0 × 10 ²³ g
C)1 g = 6.0 × 10 ²³ amu
D)1 g = 1.7 × 10 ⁻²⁴ amu
E)None of these choices are correct.

Question 37

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

A)HNO
B)H ₂NO ₂
C)HN ₆O ₁₆
D)HN ₁₆O ₇
E)H ₂NO ₃

Question 38

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass O. If its molar mass is between 94 and 98 g/mol, what is its molecular formula?

A)NH ₂O ₅
B)N ₂H ₄O ₄
C)N ₃H ₃O ₃
D)N ₄H ₈O ₂
E)N ₂H ₂O ₄

Question 39

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

A)50.0 g of Li ₂O
B)75.0 g of CaO
C)200.0 g of Fe ₂O ₃
D)50.0 g of CO ₂
E)100.0 g of SO ₃

Question 40

Alkanes are compounds of carbon and hydrogen with the general formula C_nH₂n₊₂. An alkane component of gasoline has a molar mass of between 125 and 130 g/mol. What is the value of n for this alkane?

A)4
B)9
C)10
D)13
E)14

Question 41

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO₂ and 0.226 g H₂O. What is its empirical formula?

A)C ₂H ₃O ₄
B)C ₃H ₄O ₂
C)C ₄H ₃O ₂
D)C ₅H ₁₂O ₄
E)C ₂H ₂O

Question 42

Balance the following equation: B₂O₃(s) + HF(l) → BF₃(g) + H₂O(l)

A)B ₂O ₃( s)+ 6HF( l)→ 2BF ₃( g)+ 3H ₂O( l)
B)B ₂O ₃( s)+ H ₆F ₆( l)→ B ₂F ₆( g)+ H ₆O ₃( l)
C)B ₂O ₃( s)+ 2HF( l)→ 2BF ₃( g)+ H ₂O( l)
D)B ₂O ₃( s)+ 3HF( l)→ 2BF ₃( g)+ 3H ₂O( l)
E)B ₂O ₃( s)+ 6HF( l)→ 2BF ₃( g)+ 6H ₂O( l)

Question 43

Ammonia will react with fluorine to produce dinitrogen tetrafluoride and hydrogen fluoride (used in production of aluminum, in uranium processing, and in frosting of light bulbs). 2NH₃(g) + 5F₂(g) → N₂F₄(g) + 6HF(g)
How many moles of NH₃ are needed to react completely with 13.6 mol of F₂?

A)34.0 mol
B)27.2 mol
C)6.80 mol
D)5.44 mol
E)2.27 mol

Question 44

Balance the following equation: C₈H₁₈O₃(l) + O₂(g) → H₂O(g) + CO₂(g)

A)C ₈H ₁₈O ₃( l)+ 8O ₂( g)→ 9H ₂O( g)+ 8CO ₂( g)
B)C ₈H ₁₈O ₃( l)+ 11O ₂( g)→ 9H ₂O( g)+ 8CO ₂( g)
C)2C ₈H ₁₈O ₃( l)+ 22O ₂( g)→ 9H ₂O( g)+ 16CO ₂( g)
D)C ₈H ₁₈O ₃( l)+ 13O ₂( g)→ 18H ₂O( g)+ 8CO ₂( g)
E)2C ₈H ₁8O ₃( l)+ 17O ₂( g)→ 18H ₂O( g)+ 16CO ₂( g)

Question 45

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

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

Question 46

Balance the following equation: UO₂(s) + HF(l) → UF₄(s) + H₂O(l)

A)UO ₂( s)+ 2HF( l)→ UF ₄( s)+ H ₂O( l)
B)UO ₂( s)+ 4HF( l)→ UF ₄( s)+ 2H ₂O( l)
C)UO ₂ ( s)+ H ₄F ₄( l)→ UF ₄ ( s)+ H ₄O ₂( l)
D)UO ₂( s)+ 4HF( l)→ UF ₄( s)+ 4H ₂O( l)
E)UO ₂( s)+ 8HF( l)→ 2UF ₄( s)+ 4H ₂O( l)

Question 47

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO₂ and 0.226 g H₂O. If its molar mass is between 158 and 167 g/mol, what is its molecular formula?

A)C ₄H ₆O ₇
B)C ₆H ₈O ₅
C)C ₇H ₁₂O ₄
D)C ₄H ₃O ₂
E)C ₈H ₆O ₄

Question 48

Sulfur dioxide reacts with chlorine to produce thionyl chloride (used as a drying agent for inorganic halides) and dichlorine oxide (used as a bleach for wood, pulp, and textiles). SO₂(g) + 2Cl₂(g) → SOCl₂(g) + Cl₂O(g)
If 0.400 mol of Cl₂ reacts with excess SO₂, how many moles of Cl₂O are formed?

A)0.800 mol
B)0.400 mol
C)0.200 mol
D)0.100 mol
E)0.0500 mol

Question 49

How many molecules of molecular oxygen react with four molecules of NH₃ to form four molecules of nitrogen monoxide and six molecules of water?

A)2
B)10
C)3
D)4
E)5

Question 50

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

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

Question 51

Lead(II) sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form lead(II) sulfate and water. How many grams of hydrogen peroxide are needed to react completely with 265 g of lead(II) sulfide?

A)151 g
B)123 g
C)50.3 g
D)37.7 g
E)9.41 g

Question 52

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) → 2NH₃(g)
How many grams of nitrogen are needed to produce 325 grams of ammonia?

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

Question 53

Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decaoxide and water. PH₃(g) + O₂(g) → P₄O₁₀(s) + H₂O(g) [unbalanced]
Calculate the mass of P₄O₁₀(s) formed when 225 g of PH₃ reacts with excess oxygen.

A)1880 g
B)940. g
C)900. g
D)470 g
E)56.3 g

Question 54

In the combustion analysis of 0.1127 g of glucose (C₆H₁₂O₆), what mass, in grams, of CO₂ would be produced?

A)0.0451 g
B)0.0825 g
C)0.1652 g
D)0.4132 g
E)1.466 g

Question 55

Aluminum metal reacts with chlorine gas to form solid aluminum trichloride, AlCl₃. What mass of chlorine gas is needed to react completely with 163 g of aluminum?

A)214 g
B)245 g
C)321 g
D)489 g
E)643 g

Question 56

Balance the following equation for the combustion of benzene: C₆H₆(l) + O₂(g) → H₂O(g) + CO₂(g)

A)C ₆H ₆( l)+ 9O ₂( g)→ 3H ₂O( g)+ 6CO ₂( g)
B)C ₆H ₆( l)+ 9O ₂( g)→ 6H ₂O( g)+ 6CO ₂( g)
C)2C ₆H ₆(l)+ 15O ₂(g)→ 6H ₂O(g)+ 12CO ₂( g)
D)C ₆H ₆( l)+ 15O ₂( g)→ 3H ₂O( g)+ 6CO ₂( g)
E)2C ₆H ₆( l)+ 9O ₂( g)→ 6H ₂O( g)+ 12CO ₂( g)

Question 57

How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH₃? 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g)

A)469.7 g
B)300.6 g
C)250.0 g
D)3.406 g
E)2.180 g

Question 58

Hydroxylamine hydrochloride is a powerful reducing agent which is used as a polymerization catalyst. It contains 5.80 mass % H, 20.16 mass % N, 23.02 mass % O, and 51.02 mass % Cl. What is its empirical formula?

A)H ₂N ₇O ₈Cl ₁₈
B)H ₂N ₂O ₂Cl
C)HN ₃O ₄C _l9
D)H ₄NOCl
E)H ₄NOCl ₂

Question 59

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

A)Ca ₃(PO ₄)2( s)+ 3SiO ₂( s)+ 8C( s)→ 3CaSiO ₃( s)+ 8CO( g)+ P4( s)
B)Ca ₃(PO ₄)2( s)+ 3SiO ₂( s)+ 14C(s)→ 3CaSiO ₃( s)+ 14CO( g)+ P ₄( s)
C)Ca ₃(PO ₄)2( s)+ 3SiO ₂( s)+ 8C( s)→ 3CaSiO ₃( s)+ 8CO( g)+ 2P ₄( s)
D)2Ca ₃(PO ₄)2( s)+ 6SiO ₂( s)+ 10C( s)→ 6CaSiO ₃( s)+ 10CO( g)+ P ₄( s)
E)2Ca ₃(PO ₄)2( s)+ 6SiO ₂( s)+ 10C( s)→ 6CaSiO ₃( s)+ 10CO( g)+ 4P ₄( s)

Question 60

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3SCl₂(l) + 4NaF(s) → SF₄(g) + S₂Cl₂(l) + 4NaCl(s)

A)1940 g
B)1510 g
C)754 g
D)205 g
E)51.3 g

Question 61

Aluminum reacts with oxygen to produce aluminum oxide which can be used as an adsorbent, desiccant, or catalyst for organic reactions. 4Al(s) + 3O₂(g) → 2Al₂O₃(s)
A mixture of 82.49 g of aluminum (ℳ = 26.98 g/mol) and 117.65 g of oxygen (ℳ= 32.00 g/mol) is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete.

A)Oxygen is the limiting reactant; 19.81 g of aluminum remain.
B)Oxygen is the limiting reactant; 35.16 g of aluminum remain.
C)Aluminum is the limiting reactant; 16.70 g of oxygen remain.
D)Aluminum is the limiting reactant; 35.16 g of oxygen remain.
E)Aluminum is the limiting reactant; 44.24 g of oxygen remain.

Question 62

The iodine "clock reaction" involves the following sequence of reactions occurring in a reaction mixture in a single beaker. IO₃(aq) + 5I^-(aq) + 6H⁺(aq) → 3I₂(aq) + 3H₂O(l)
I₂(aq) + 2S₂O₃^2-(aq) → 2I^-(aq) + S₄O₆^2-(aq)
The molecular iodine (I₂) formed in reaction 1 is immediately used up in reaction 2, so that no iodine accumulates. In one experiment, a student made up a reaction mixture which initially contained 0.0020 mol of iodate ions (IO₃⁻). If the iodate ions reacted completely, how many moles of thiosulfate ions (S₂O₃²⁻) were needed in reaction 2, in order to react completely with the iodine (I₂) produced in reaction 1?

A)0.0020 mol
B)0.012 mol
C)0.0040 mol
D)0.0010 mol
E)0.0060 mol

Question 63

An important reaction sequence in the industrial production of nitric acid is the following: N₂(g) + 3H₂(g) → 2NH₃(g)
4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l)
Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

A)12.5 mol O ₂
B)20.0 mol O ₂
C)25.0 mol O ₂
D)50.0 mol O ₂
E)100. mol O ₂

Question 64

Methanol (CH₄O) is converted to bromomethane (CH₃Br) as follows: CH₄O + HBr → CH₃Br + H₂O
If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr, what is the percentage yield?

A)40.9%
B)82.6%
C)100%
D)121%
E)245%

Question 65

Tetraphosphorus hexaoxide ( ℳ = 219.9 g/mol) is formed by the reaction of phosphorus with oxygen gas. P₄(s) + 3O₂(g) → P₄O₆(s)
If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P₄O₆, what is the percent yield for the reaction?

A)57.5%
B)48.8%
C)38.0%
D)32.4%
E)16.3%

Question 66

What is the percent yield for the reaction PCl₃(g) + Cl₂(g) → PCl₅(g)
If 119.3 g of PCl₅ (ℳ = 208.2 g/mol) are formed when 61.3 g of Cl₂ (ℳ = 70.91 g/mol) react with excess PCl₃?

A)195%
B)85.0%
C)66.3%
D)51.4%
E)43.7%

Question 67

Magnesium (used in the manufacture of light alloys) reacts with iron(III) chloride to form magnesium chloride and iron. 3Mg(s) + 2FeCl₃(s) → 3MgCl₂(s) + 2Fe(s)
A mixture of 41.0 g of magnesium (ℳ = 24.31 g/mol) and 175 g of iron(III) chloride (ℳ= 162.2 g/mol) is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete.

A)Limiting reactant is Mg; 67 g of FeCl ₃ remain.
B)Limiting reactant is Mg; 134 g of FeCl ₃ remain.
C)Limiting reactant is Mg; 104 g of FeCl ₃ remain.
D)Limiting reactant is FeCl ₃; 2 g of Mg remain.
E)Limiting reactant is FeCl ₃; 87 g of Mg remain.

Question 68

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) → 3I₂(aq) + 3H₂O(l)
2.I₂(aq) + 2S₂O₃²⁻(aq) → 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?

A)IO ₃ ⁻( aq)+ 3I ⁻( aq)+ 2S ₂O3 ₂ ⁻ aq)+ 6H+( aq)→ 2I ₂( aq)+ S ₄O6 ₂ ⁻( aq)+ 3H ₂O( l)
B)IO ₃( aq)+ 4S ₂O3 ₂ ⁻( aq)+ 6H+( aq)→ I ⁻( aq)+ 2S ₄O6 ₂ ⁻( aq)+ 3H ₂O( l)
C)IO ₃⁻ aq)+ 6S ₂O3 ₂ ⁻ aq)+ 6H+( aq)→ I ^-( aq)+ 3S ₄O6 ₂ ⁻ aq)+ 3H ₂O( l)
D)IO3 ⁻( aq)+ I2( aq)+ 8S2O32 ⁻( aq)+ 6H+( aq)→ 3I-( aq)+ 4S4O62 ⁻( aq)+ 3H2O( l)
E)IO3( aq)+ 2I2( aq)+ 6S2O32 ⁻(aq)+ 6H+( aq)→ 5I ^-( aq)+ 3S4O62−( aq)+ 3H2O( l)

Question 69

Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride.

A)Potassium is the limiting reactant; 2.47 g of chlorine remain.
B)Potassium is the limiting reactant; 7.23 g of chlorine remain.
C)Chlorine is the limiting reactant; 4.64 g of potassium remain.
D)Chlorine is the limiting reactant; 2.70 g of potassium remain.
E)No limiting reagent: the reactants are present in the correct stoichiometric ratio.

Question 70

Magnesium reacts with iron(III) chloride to form magnesium chloride (which can be used in fireproofing wood and in disinfectants) and iron. 3Mg(s) + 2FeCl₃(s) → 3MgCl₂(s) + 2Fe(s)
A mixture of 41.0 g of magnesium (ℳ = 24.31 g/mol) and 175 g of iron(III) chloride (ℳ = 162.2 g/mol) is allowed to react. What mass of magnesium chloride (ℳ = 95.21 g/mol) is formed?

A)68.5 g MgCl ₂
B)77.0 g MgCl ₂
C)71.4 g MgCl ₂
D)107 g MgCl ₂
E)154 g MgCl ₂

Question 71

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) → 2CO(g)
Fe₃O₄(s) + 4CO(g) → 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?

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

Question 72

Aluminum oxide (used as an adsorbent or a catalyst for organic reactions) forms when aluminum reacts with oxygen. 4Al(s) + 3O₂(g) → 2Al₂O₃(s)
A mixture of 82.49 g of aluminum (ℳ= 26.98 g/mol) and 117.65 g of oxygen (ℳ = 32.00 g/mol) is allowed to react. What mass of aluminum oxide (ℳ = 101.96 g/mol) can be formed?

A)155.8 g
B)200.2 g
C)249.9 g
D)311.7 g
E)374.9 g