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 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

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) 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)

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

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

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) 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)

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

Exam 3: Stoichiometry of Formulas and Equations

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?

(Multiple Choice)

4.8/5

(30)

Question 21

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.

(True/False)

4.8/5

(36)

Question 22

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

(True/False)

4.9/5

(36)

Question 23

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

(Multiple Choice)

4.7/5

(37)

Question 24

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

(True/False)

4.8/5

(39)

Question 25

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.

(Multiple Choice)

4.8/5

(39)

Question 26

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?

(Multiple Choice)

4.8/5

(40)

Question 27

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.

(Multiple Choice)

4.9/5

(40)

Question 28

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

(Multiple Choice)

4.9/5

(29)

Question 29

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

(True/False)

4.7/5

(34)

Question 30

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.

(Multiple Choice)

4.9/5

(30)

Question 31

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?

(Multiple Choice)

4.9/5

(45)

Question 32

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

(Multiple Choice)

4.9/5

(35)

Question 33

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

(Multiple Choice)

4.7/5

(38)

Question 34

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

(Multiple Choice)

4.8/5

(32)

Question 35

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

(True/False)

4.7/5

(42)

Question 36

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.

(Multiple Choice)

4.8/5

(34)

Question 37

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

(True/False)

4.7/5

(35)

Question 38

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

(Multiple Choice)

4.8/5

(38)

Question 39

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?

(Multiple Choice)

4.7/5

(30)

Question 40

Showing 21 - 40 of 72

Exam 3: Stoichiometry of Formulas and Equations

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.

The formula CH3O0.5 is an example of an empirical formula.

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

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

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.

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?

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.

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

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

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.

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?

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

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

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

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

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.

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

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

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?

Keys to the Study of Chemistry: Definitions, Units, and Problem Solving

The Components of Matter

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and Reaction Direction

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

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.

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

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

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.

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?

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.

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?

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

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.

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

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