Question 1

How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH3? 4NH3(g) + 5O2(g) F1F1F1S1F1F1F10 4NO(g) + 6H2O(g)

Accepted Answer

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

Question 2

Calculate the molar mass of rubidium carbonate, Rb2CO3.

Accepted Answer

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 
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 3

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

Accepted Answer

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

Question 4

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?

Accepted Answer

A)  H2N7O8Cl18 
B)  H2N2O2Cl 
C)  HN3O4Cl9 
D)  H4NOCl 
E)  H4NOCl2 
A)  H2N7O8Cl18 
B)  H2N2O2Cl 
C)  HN3O4Cl9 
D)  H4NOCl 
E)  H4NOCl2

Question 5

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.

Accepted Answer

A)  9.490 × 1025 Cr atoms 
B)  2.248 × 1024 Cr atoms 
C)  1.124 × 1024 Cr atoms 
D)  3.227 × 1023 Cr atoms 
E)  1.613 × 1023 Cr atoms 
A)  9.490 × 1025 Cr atoms 
B)  2.248 × 1024 Cr atoms 
C)  1.124 × 1024 Cr atoms 
D)  3.227 × 1023 Cr atoms 
E)  1.613 × 1023 Cr atoms

Question 6

Balance the following equation for the combustion of butane, a hydrocarbon used in gas lighters:
C4H10(g) + O2(g) F1F1F1S1F1F1F10 CO2(g) + H2O(l)

Accepted Answer

2C₄H₁₀(g) + 1

Question 7

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?

Accepted Answer

A)  2.0 × 1022 
B)  2.2 × 1022 
C)  5.8 × 1023 
D)  1.7 × 1025 
E)  1.8 × 1025 
A)  2.0 × 1022 
B)  2.2 × 1022 
C)  5.8 × 1023 
D)  1.7 × 1025 
E)  1.8 × 1025

Question 8

The insecticide DDT was formerly in widespread use, but now it is severely restricted owing to its adverse environmental effects. It is prepared as follows:
C2HCl3O + 2C6H5Cl F1F1F1S1F1F1F10 C14H9Cl5 + H2O
chloral chlorobenzene DDT
If 10.00 g of chloral were reacted with 10.00 g of chlorobenzene
a. what is the maximum amount (mol) of DDT which could be formed?
b. what is the limiting reagent?
c. what is the % yield, if 12.15 g of DDT is produced?

Accepted Answer

a. 0.0444 mol DDT
b.

Question 9

One mole of O2 has a mass of 16.0 g.

Accepted Answer

A) True 
 B)False

Question 10

In 0.20 mole of phosphoric acid, H3PO4
a. how many H atoms are there?
b. what is the total number of atoms?
c. how many moles of O atoms are there?

Accepted Answer

a. 3.61 × 10²³ H atoms

Question 11

Ammonia, NH3, is produced industrially from nitrogen and hydrogen as follows:
N2(g) + 3H2(g) F1F1F1S1F1F1F10 2NH3(g)
What mass, of which starting material, will remain when 30.0 g of N2 and 10.0 g of H2 react until the limiting reagent is completely consumed?

Accepted Answer

3.52 g of

Question 12

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) F1F1F1S1F1F1F10 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 
A)  1070 g 
B)  535 g 
C)  267 g 
D)  178 g 
E)  108 g

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.

Accepted Answer

A) True 
 B)False

Question 14

Magnesium (used in the manufacture of light alloys) reacts with iron(III) chloride to form magnesium chloride and iron. 3Mg(s) + 2FeCl3(s) F1F1F1S1F1F1F10 3MgCl2(s) + 2Fe(s)
A mixture of 41.0 g of magnesium (   = 24.31 g/mol) and 175 g of iron(III) chloride (   = 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.

Accepted Answer

A)  Limiting reactant is Mg; 67 g of FeCl3 remain. 
B)  Limiting reactant is Mg; 134 g of FeCl3 remain. 
C)  Limiting reactant is Mg; 104 g of FeCl3 remain. 
D)  Limiting reactant is FeCl3; 2 g of Mg remain. 
E)  Limiting reactant is FeCl3; 87 g of Mg remain. 
A)  Limiting reactant is Mg; 67 g of FeCl3 remain. 
B)  Limiting reactant is Mg; 134 g of FeCl3 remain. 
C)  Limiting reactant is Mg; 104 g of FeCl3 remain. 
D)  Limiting reactant is FeCl3; 2 g of Mg remain. 
E)  Limiting reactant is FeCl3; 87 g of Mg remain.

Question 15

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

Accepted Answer

A)  4.00 × 102 g 
B)  25.0 g 
C)  17.0 g 
D)  4.00 × 10-2 g 
E)  2.50 × 10-3 g 
A)  4.00 × 102 g 
B)  25.0 g 
C)  17.0 g 
D)  4.00 × 10-2 g 
E)  2.50 × 10-3 g

Question 16

For a sample consisting of 2.50 g of methane, CH4, calculate
a. the number of moles of methane present.
b. the total number of atoms present.

Accepted Answer

a. 0.156 m

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

Gaseous methanol (CH4O) reacts with oxygen gas to produce carbon dioxide gas and liquid water. Write a balanced equation for this process.

Accepted Answer

2CH₄O(g) +

Question 19

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?

Accepted Answer

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

Question 20

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?

Accepted Answer

A)  C2H3O4 
B)  C3H4O2 
C)  C4H3O2 
D)  C5H12O4 
E)  C2H2O 
A)  C2H3O4 
B)  C3H4O2 
C)  C4H3O2 
D)  C5H12O4 
E)  C2H2O

Exam 3: Stoichiometry of Formulas and Equations

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)

Calculate the molar mass of rubidium carbonate, Rb2CO3.

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

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?

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.

Balance the following equation for the combustion of butane, a hydrocarbon used in gas lighters: C4H10(g) + O2(g)  CO2(g) + H2O(l)

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?

One mole of O2 has a mass of 16.0 g.

In 0.20 mole of phosphoric acid, H3PO4 a. how many H atoms are there? b. what is the total number of atoms? c. how many moles of O atoms are there?

Ammonia, NH3, is produced industrially from nitrogen and hydrogen as follows: N2(g) + 3H2(g)  2NH3(g) What mass, of which starting material, will remain when 30.0 g of N2 and 10.0 g of H2 react until the limiting reagent is completely consumed?

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?

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.

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

For a sample consisting of 2.50 g of methane, CH4, calculate a. the number of moles of methane present. b. the total number of atoms present.

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

Gaseous methanol (CH4O) reacts with oxygen gas to produce carbon dioxide gas and liquid water. Write a balanced equation for this process.

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?

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?

Keys to the Study of Chemistry

The Components of Matter

The 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: Bonding, Structure, and Reactivity

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 the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

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)

Calculate the molar mass of rubidium carbonate, Rb₂CO₃.

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

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.

Balance the following equation for the combustion of butane, a hydrocarbon used in gas lighters: C₄H₁₀(g) + O₂(g)  CO₂(g) + H₂O(l)

One mole of O₂ has a mass of 16.0 g.

In 0.20 mole of phosphoric acid, H₃PO₄ a. how many H atoms are there? b. what is the total number of atoms? c. how many moles of O atoms are there?

Ammonia, NH₃, is produced industrially from nitrogen and hydrogen as follows: N₂(g) + 3H₂(g)  2NH₃(g) What mass, of which starting material, will remain when 30.0 g of N₂ and 10.0 g of H₂react until the limiting reagent is completely consumed?

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?

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.

For a sample consisting of 2.50 g of methane, CH₄, calculate a. the number of moles of methane present. b. the total number of atoms present.

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

Gaseous methanol (CH₄O) reacts with oxygen gas to produce carbon dioxide gas and liquid water. Write a balanced equation for this process.

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 CO₂and 0.226 g H₂O. What is its empirical formula?