Question 1

Which of the following is least helpful in balancing an equation?

Accepted Answer

A) Use a balance sheet to keep track of the number of elements. 
B) Try different coefficients and subscripts to balance the number of atoms. 
C) Begin with elements that appear only once on each side of the equation. 
D) Change only the coefficients to balance the number of atoms. 
A) Use a balance sheet to keep track of the number of elements. 
B) Try different coefficients and subscripts to balance the number of atoms. 
C) Begin with elements that appear only once on each side of the equation. 
D) Change only the coefficients to balance the number of atoms.

Question 2

What is the theoretical yield of vanadium,in moles,that can be produced by the reaction of 1.0 mole of V2O5 with 4.0 moles of calcium based on the following chemical equation? V2O5(s)+ 5Ca(l)→ 2V(l)+ 5CaO(s)

Accepted Answer

A) 1.0 mol 
B) 1.6 mol 
C) 2.0 mol 
D) 0.80 mol 
E) 3.2 mol 
A) 1.0 mol 
B) 1.6 mol 
C) 2.0 mol 
D) 0.80 mol 
E) 3.2 mol

Question 3

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

Accepted Answer

A) True 
 B)False

Question 4

What is the mass percent of oxygen in barium perchlorate?

Accepted Answer

A) 4.7% 
B) 8.5% 
C) 23.4% 
D) 38.1% 
E) 19.0% 
A) 4.7% 
B) 8.5% 
C) 23.4% 
D) 38.1% 
E) 19.0%

Question 5

What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? ___ Al4C3 + ___ H2O → ___ Al(OH)3 + ___ CH4

Accepted Answer

A) 3 
B) 4 
C) 6 
D) 12 
E) 24 
A) 3 
B) 4 
C) 6 
D) 12 
E) 24

Question 6

What is the molar mass of nicotine,C10H14N2?

Accepted Answer

A) 134 g/mol 
B) 148 g/mol 
C) 158 g/mol 
D) 210 g/mol 
E) 162 g/mol 
A) 134 g/mol 
B) 148 g/mol 
C) 158 g/mol 
D) 210 g/mol 
E) 162 g/mol

Question 7

What is the theoretical yield of aluminum that can be produced by the reaction of 60.0 g of aluminum oxide with 30.0 g of carbon according to the following chemical equation? Al2O3 + 3C → 2Al + 3CO

Accepted Answer

A) 15.9 g 
B) 31.8 g 
C) 44.9 g 
D) 63.6 g 
E) 67.4 g 
A) 15.9 g 
B) 31.8 g 
C) 44.9 g 
D) 63.6 g 
E) 67.4 g

Question 8

Calculate the mass of 3.00 moles of CF2Cl2.

Accepted Answer

A) 3.00 g 
B) 174 g 
C) 363 g 
D) 1.81 × 1024 g 
E) 40.3 
A) 3.00 g 
B) 174 g 
C) 363 g 
D) 1.81 × 1024 g 
E) 40.3

Question 9

The molecular formula is a whole number multiple of the empirical formula.

Accepted Answer

A) True 
 B)False

Question 10

What is the coefficient of O2 when the following equation is properly balanced with the smallest set of whole numbers? __ C2H4 + __ O2 → __ CO2 + __ H2O

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 6 
A) 1 
B) 2 
C) 3 
D) 4 
E) 6

Question 11

What is the mass of 7.80 × 1018 carbon atoms? (NA = 6.022 × 1023 mol-1)

Accepted Answer

A) 1.30 × 10-5 g 
B) 6.43 × 103 g 
C) 7.80 × 1018 g 
D) 1.56 × 10-4 g 
E) 12.01 g 
A) 1.30 × 10-5 g 
B) 6.43 × 103 g 
C) 7.80 × 1018 g 
D) 1.56 × 10-4 g 
E) 12.01 g

Question 12

What is the empirical formula for a 100-g sample containing 87.42 g of nitrogen and 12.58 g of hydrogen?

Accepted Answer

A) NH 
B) N2H 
C) NH2 
D) NH3 
E) N7H 
A) NH 
B) N2H 
C) NH2 
D) NH3 
E) N7H

Question 13

When octane (C8H18)is burned in a particular internal combustion engine,the yield of products (carbon dioxide and water)is 93%.What mass of carbon dioxide will be produced in this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?

Accepted Answer

A) 13 g 
B) 12 g 
C) 21 g 
D) 54 g 
E) 43 g 
A) 13 g 
B) 12 g 
C) 21 g 
D) 54 g 
E) 43 g

Question 14

What mass of sodium carbonate is required for complete reaction with 8.35 g of nitric acid to produce sodium nitrate,carbon dioxide,and water?

Accepted Answer

A) 28.1 g 
B) 14.04 g 
C) 4.96 g 
D) 7.02 g 
E) 400.0 g 
A) 28.1 g 
B) 14.04 g 
C) 4.96 g 
D) 7.02 g 
E) 400.0 g

Question 15

What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? ___ PCl3(l)+ ___ H2O(l)→ ___ H3PO3(aq)+ ___ HCl(aq)

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 5 
E) None of these answers is correct. 
A) 1 
B) 2 
C) 3 
D) 5 
E) None of these answers is correct.

Question 16

How many grams are contained in a 0.183 mol sample of ammonium phosphate?

Accepted Answer

A) 1.23 × 10-3 g 
B) 617 g 
C) 20.7 g 
D) 27.3 g 
E) 815.1 g 
A) 1.23 × 10-3 g 
B) 617 g 
C) 20.7 g 
D) 27.3 g 
E) 815.1 g

Question 17

The molecular formula is a whole number multiple of the empirical formula.

Accepted Answer

A) True 
 B)False

Question 18

The first step in the Ostwald process for producing nitric acid is as follows: 4NH3(g)+ 5O2(g)→ 4NO(g)+ 6H2O(g).
If the reaction of 15.0 g of ammonia with 15.0 g of oxygen gas yields 8.70 g of nitric oxide,what is the percent yield of this reaction?

Accepted Answer

A) 29.0% 
B) 32.9% 
C) 49.5% 
D) 61.8% 
E) 77.3% 
A) 29.0% 
B) 32.9% 
C) 49.5% 
D) 61.8% 
E) 77.3%

Question 19

Which of the following substances contains the greatest mass of carbon?

Accepted Answer

A) 100 g CH4 
B) 100 g C2H4 
C) 100 g CCl4 
D) 100 g CH2Cl2 
E) 100 g CO2 
A) 100 g CH4 
B) 100 g C2H4 
C) 100 g CCl4 
D) 100 g CH2Cl2 
E) 100 g CO2

Question 20

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.

Accepted Answer

A) Chlorine is the limiting reactant; 1.14 g of potassium remain. 
B) Potassium is the limiting reactant; 2.00 g of chlorine remain. 
C) Potassium is the limiting reactant; 2.47 g of chlorine remain. 
D) Chlorine is the limiting reactant; 3.07 g of potassium remain. 
E) Potassium is the limiting reactant; 4.50 g of chlorine remain. 
A) Chlorine is the limiting reactant; 1.14 g of potassium remain. 
B) Potassium is the limiting reactant; 2.00 g of chlorine remain. 
C) Potassium is the limiting reactant; 2.47 g of chlorine remain. 
D) Chlorine is the limiting reactant; 3.07 g of potassium remain. 
E) Potassium is the limiting reactant; 4.50 g of chlorine remain.

Exam 3: Stoichiometry Ratios of Combination

Which of the following is least helpful in balancing an equation?

What is the theoretical yield of vanadium,in moles,that can be produced by the reaction of 1.0 mole of V2O5 with 4.0 moles of calcium based on the following chemical equation? V2O5(s)+ 5Ca(l)→ 2V(l)+ 5CaO(s)

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

What is the mass percent of oxygen in barium perchlorate?

What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? ___ Al4C3 + ___ H2O → ___ Al(OH)3 + ___ CH4

What is the molar mass of nicotine,C10H14N2?

What is the theoretical yield of aluminum that can be produced by the reaction of 60.0 g of aluminum oxide with 30.0 g of carbon according to the following chemical equation? Al2O3 + 3C → 2Al + 3CO

Calculate the mass of 3.00 moles of CF2Cl2.

The molecular formula is a whole number multiple of the empirical formula.

What is the coefficient of O2 when the following equation is properly balanced with the smallest set of whole numbers? __ C2H4 + __ O2 → __ CO2 + __ H2O

What is the mass of 7.80 × 1018 carbon atoms? (NA = 6.022 × 1023 mol-1)

What is the empirical formula for a 100-g sample containing 87.42 g of nitrogen and 12.58 g of hydrogen?

When octane (C8H18)is burned in a particular internal combustion engine,the yield of products (carbon dioxide and water)is 93%.What mass of carbon dioxide will be produced in this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?

What mass of sodium carbonate is required for complete reaction with 8.35 g of nitric acid to produce sodium nitrate,carbon dioxide,and water?

What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? ___ PCl3(l)+ ___ H2O(l)→ ___ H3PO3(aq)+ ___ HCl(aq)

How many grams are contained in a 0.183 mol sample of ammonium phosphate?

The molecular formula is a whole number multiple of the empirical formula.

The first step in the Ostwald process for producing nitric acid is as follows: 4NH3(g)+ 5O2(g)→ 4NO(g)+ 6H2O(g). If the reaction of 15.0 g of ammonia with 15.0 g of oxygen gas yields 8.70 g of nitric oxide,what is the percent yield of this reaction?

Which of the following substances contains the greatest mass of carbon?

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.

Chemistry: the Central Science

Atoms Molecules and Ions

Reactions in Aqueous Solutions

Thermochemistry

Quantum Theory and the Electronic Structure of Atoms

Electron Configuration and the Periodic Table

Chemical Bonding I Basic Concepts

Chemical Bonding Ii Molecular Geometry and Bonding Theories

Gases

Intermolecular Forces and the Physical Properties of Liquids and Solids

Modern Materials

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Entropy Free Energy and Equilibrium

Electrochemistry

Nuclear Chemistry

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Nonmetallic Elements and Their Compounds

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Filters

What is the theoretical yield of vanadium,in moles,that can be produced by the reaction of 1.0 mole of V₂O₅ with 4.0 moles of calcium based on the following chemical equation? V₂O₅(s)+ 5Ca(l)→ 2V(l)+ 5CaO(s)

What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? _ Al₄C₃ + _ H₂O → _ Al(OH)₃ + _ CH₄

What is the molar mass of nicotine,C₁₀H₁₄N₂?

What is the theoretical yield of aluminum that can be produced by the reaction of 60.0 g of aluminum oxide with 30.0 g of carbon according to the following chemical equation? Al₂O₃ + 3C → 2Al + 3CO

Calculate the mass of 3.00 moles of CF₂Cl₂.

What is the coefficient of O2 when the following equation is properly balanced with the smallest set of whole numbers? C₂H₄ + O₂ → CO₂ + H₂O

What is the mass of 7.80 × 10¹⁸ carbon atoms? (N_A = 6.022 × 10²³ mol^-1)

When octane (C₈H₁₈)is burned in a particular internal combustion engine,the yield of products (carbon dioxide and water)is 93%.What mass of carbon dioxide will be produced in this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?

What is the coefficient of H₂O when the following equation is properly balanced with the smallest set of whole numbers? _ PCl₃(l)+ _ H₂O(l)→ _ H₃PO₃(aq)+ _ HCl(aq)

The first step in the Ostwald process for producing nitric acid is as follows: 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g). If the reaction of 15.0 g of ammonia with 15.0 g of oxygen gas yields 8.70 g of nitric oxide,what is the percent yield of this reaction?