Question 1

What is the molar mass of acetaminophen, C8H9NO2?

Accepted Answer

A) 43 g/mol 
B) 76 g/mol 
C) 151 g/mol 
D) 162 g/mol 
E) 125 g/mol 
A) 43 g/mol 
B) 76 g/mol 
C) 151 g/mol 
D) 162 g/mol 
E) 125 g/mol

Question 2

A chemistry student determined the empirical formula for tungsten oxide (WxOy).To do so, he heated tungsten with oxygen in a crucible.The data that he recorded are shown below:   What is the empirical formula of tungsten oxide?

Accepted Answer

Question 3

The mass of 1.63 * 1021 silicon atoms is

Accepted Answer

A) (2.71 * 10-23 g.) 
B) (4.58 * 1022 g.) 
C) 28.08 g. 
D) 1.04 * 104 g. 
E) (7.60 * 10-2 g.) 
A) (2.71 * 10-23 g.) 
B) (4.58 * 1022 g.) 
C) 28.08 g. 
D) 1.04 * 104 g. 
E) (7.60 * 10-2 g.)

Question 4

How many moles of iron are present in an iron cylinder that weighs 25 g?

Accepted Answer

The answer of How many moles of iron are present...

Question 5

Common gases used in laboratories are generally obtained from pressurized metal gas cylinders, but for small amounts of occasionally-used gases, it is sometimes easier just to prepare them chemically.For example, oxygen gas can be prepared by heating KMnO4(s)according to the following chemical reaction:
2KMnO4(s)$\rarr$ K2MnO4(s)+ MnO2(s)+ O2(g)
How many grams of KMnO4 would you need to produce 0.27 moles of O2, assuming 100% conversion? The molar mass of KMnO4 is 158.034 g/mol.

Accepted Answer

Question 6

What mass of sodium nitrate would be produced from the complete reaction of 1.00 mol of lead nitrate?
2 NaCl + Pb(NO3 )2 $\rarr$ 2 NaNO3 + PbCl2

Accepted Answer

Question 7

The element oxygen consists of three naturally occuring isotopes: 16O, 17O, and 18O.The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes?

Accepted Answer

A) More than 50% of all O atoms are 17O. 
B) Almost all O atoms are 18O. 
C) Almost all O atoms are 17O. 
D) The isotopes all have the same abundance, i.e.33.3%. 
E) The abundances of 17O and 18O are very small. 
A) More than 50% of all O atoms are 17O. 
B) Almost all O atoms are 18O. 
C) Almost all O atoms are 17O. 
D) The isotopes all have the same abundance, i.e.33.3%. 
E) The abundances of 17O and 18O are very small.

Question 8

When 22.0 g NaCl and 21.0 g H2SO4 are mixed and react according to the equation below, which is the limiting reagent? 
2NaCl + H2SO4 $\rarr$Na2SO4 + 2HCl

Accepted Answer

A) NaCl 
B) H2SO4 
C) Na2SO4 
D) HCl 
E) No reagent is limiting. 
A) NaCl 
B) H2SO4 
C) Na2SO4 
D) HCl 
E) No reagent is limiting.

Question 9

What is the mass of 0.20 mole of C2H6O (ethanol)?

Accepted Answer

A) 230 g 
B) 46 g 
C) 23 g 
D) 4.6 g 
E) None of these. 
A) 230 g 
B) 46 g 
C) 23 g 
D) 4.6 g 
E) None of these.

Question 10

Washing soda is a hydrate of sodium carbonate.Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H.What is the formula for washing soda?

Accepted Answer

A) Na2CO3.2H2O 
B) Na2CO3.4H2O 
C) Na2CO3.6H2O 
D) Na2CO3.8H2O 
E) Na2CO3.H2O 
A) Na2CO3.2H2O 
B) Na2CO3.4H2O 
C) Na2CO3.6H2O 
D) Na2CO3.8H2O 
E) Na2CO3.H2O

Question 11

How many moles of aluminum are present in an Al cylinder with a mass of 15 g?

Accepted Answer

The answer of How many moles of aluminum are present...

Question 12

How many atoms are in 4.39 g of CO2?

Accepted Answer

A) 1.80 * 1023 atoms 
B) 6.01 * 1022 atoms 
C) 1.16 * 1026 atoms 
D) 6.04 * 1024 atoms 
E) 1.81 * 1025 atoms 
A) 1.80 * 1023 atoms 
B) 6.01 * 1022 atoms 
C) 1.16 * 1026 atoms 
D) 6.04 * 1024 atoms 
E) 1.81 * 1025 atoms

Question 13

Balance the following equation using the smallest set of whole numbers, then add together the coefficients.Do not forget to count coefficients of one.The sum of the coefficients is ___ CH4 + ___ Cl2 $\rarr$ ___ CCl4 + ___ HCl

Accepted Answer

A) 4. 
B) 6. 
C) 8. 
D) 10. 
E) 12. 
A) 4. 
B) 6. 
C) 8. 
D) 10. 
E) 12.

Question 14

Nickel has a lower atomic mass than cobalt, even though it has a higher atomic number.One possible explanation is that one of the average atomic masses was miscalculated.In the case of cobalt, there is only one isotope: 100% 59Co at a mass of 58.9332 amu.For nickel, however, there are five isotopes as given in the table.   A.Using the data in the table, calculate the average atomic mass for nickel.
B.Is the atomic mass for nickel in your periodic table correct?
C.Regardless of your answer to part B, how else could you explain the observation that the atomic mass of nickel is less than the mass of cobalt, even though it has the higher atomic number?

Accepted Answer

A.58.70 amu
B.yes
C.Cobalt has 27 proton

Question 15

How many grams of sulfur are there in 6.0 g of Fe2(SO4)3?

Accepted Answer

A) 2.40 g 
B) 0.48 g 
C) 6.00 g 
D) 0.92 g 
E) 1.44 g 
A) 2.40 g 
B) 0.48 g 
C) 6.00 g 
D) 0.92 g 
E) 1.44 g

Question 16

Balance the following chemical equation:
NH3 + H2SO4 $\rarr$(NH4)2SO4

Accepted Answer

Question 17

What is the theoretical yield of PI3 if 48.0 g of I2 are reacted with an excess of phosphorus according to the following chemical equation?
2P(s)+ 3I2(s)$\rarr$2PI3(s)

Accepted Answer

Question 18

Balance the following equation using the smallest set of whole numbers, then add together the coefficients.Do not forget to count coefficients of one.The sum of the coefficients is ___ Al + ___ H2SO4 $\rarr$ ___ Al2(SO4)3 + ___ H2

Accepted Answer

A) 3. 
B) 5. 
C) 6. 
D) 9. 
E) 12. 
A) 3. 
B) 5. 
C) 6. 
D) 9. 
E) 12.

Question 19

Acetylene gas, HCCH(g), can be generated in the laboratory by adding calcium carbide to excess water, as shown in the following reaction
CaC2(s)+ H2O(l)$\rarr$HCCH(g)+ CaO(s)
How many grams of CaC2 would be required to generate 0.20 moles of HCCH(g)?

Accepted Answer

13 g of Ca

Question 20

Which one of the following chemical reactions is balanced?

Accepted Answer

A) HCl + KMnO4 $\rarr$ Cl2 + MnO2 + H2O + KCl 
B) HCl + KMnO4 $\rarr$ Cl2 + MnO2 + 2H2O + KCl 
C) 2HCl + 2KMnO4 $\rarr$ Cl2 + MnO2 + 2H2O + 2KCl 
D) 6HCl + 2KMnO4 $\rarr$ 2Cl2 + 2MnO2 + 4H2O + 2KCl 
E) 8HCl + 2KMnO4 $\rarr$ 3Cl2 + 2MnO2 + 4H2O + 2KCl 
A) HCl + KMnO4 $\rarr$ Cl2 + MnO2 + H2O + KCl 
B) HCl + KMnO4 $\rarr$ Cl2 + MnO2 + 2H2O + KCl 
C) 2HCl + 2KMnO4 $\rarr$ Cl2 + MnO2 + 2H2O + 2KCl 
D) 6HCl + 2KMnO4 $\rarr$ 2Cl2 + 2MnO2 + 4H2O + 2KCl 
E) 8HCl + 2KMnO4 $\rarr$ 3Cl2 + 2MnO2 + 4H2O + 2KCl

Exam 3: Mass Relationships in Chemical Reactions

What is the molar mass of acetaminophen, C8H9NO2?

A chemistry student determined the empirical formula for tungsten oxide (WxOy).To do so, he heated tungsten with oxygen in a crucible.The data that he recorded are shown below: What is the empirical formula of tungsten oxide?

The mass of 1.63 * 1021 silicon atoms is

How many moles of iron are present in an iron cylinder that weighs 25 g?

What mass of sodium nitrate would be produced from the complete reaction of 1.00 mol of lead nitrate? 2 NaCl + Pb(NO3 )2 →\rarr→ 2 NaNO3 + PbCl2

The element oxygen consists of three naturally occuring isotopes: 16O, 17O, and 18O.The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes?

When 22.0 g NaCl and 21.0 g H2SO4 are mixed and react according to the equation below, which is the limiting reagent? 2NaCl + H2SO4 →\rarr→ Na2SO4 + 2HCl

What is the mass of 0.20 mole of C2H6O (ethanol)?

Washing soda is a hydrate of sodium carbonate.Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H.What is the formula for washing soda?

How many moles of aluminum are present in an Al cylinder with a mass of 15 g?

How many atoms are in 4.39 g of CO2?

Balance the following equation using the smallest set of whole numbers, then add together the coefficients.Do not forget to count coefficients of one.The sum of the coefficients is ___ CH4 + ___ Cl2 →\rarr→ ___ CCl4 + ___ HCl

How many grams of sulfur are there in 6.0 g of Fe2(SO4)3?

Balance the following chemical equation: NH3 + H2SO4 →\rarr→ (NH4)2SO4

What is the theoretical yield of PI3 if 48.0 g of I2 are reacted with an excess of phosphorus according to the following chemical equation? 2P(s)+ 3I2(s) →\rarr→ 2PI3(s)

Balance the following equation using the smallest set of whole numbers, then add together the coefficients.Do not forget to count coefficients of one.The sum of the coefficients is ___ Al + ___ H2SO4 →\rarr→ ___ Al2(SO4)3 + ___ H2

Acetylene gas, HCCH(g), can be generated in the laboratory by adding calcium carbide to excess water, as shown in the following reaction CaC2(s)+ H2O(l) →\rarr→ HCCH(g)+ CaO(s) How many grams of CaC2 would be required to generate 0.20 moles of HCCH(g)?

Which one of the following chemical reactions is balanced?

Chemistry: The Study of Change

Atoms, Molecules, and Ions

Reactions in Aqueous Solution

Gases

Thermo-Chemistry

Quantum Theory and the Electronic Structure of Atoms

Periodic Relationships Among the Elements

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Chemistry in the Atmosphere

Entropy, Free Energy, and Equilibrium

Electrochemistry

Metallurgy and the Chemistry of Metals

Nonmetallic Elements and Their Compounds

Transition Metal Chemistry and Coordination Compounds

Nuclear Chemistry

Organic Chemistry

Synthetic and Natural Organic Polymers

Filters

What is the molar mass of acetaminophen, C₈H₉NO₂?

A chemistry student determined the empirical formula for tungsten oxide (W_xO_y).To do so, he heated tungsten with oxygen in a crucible.The data that he recorded are shown below: What is the empirical formula of tungsten oxide?

The mass of 1.63 * 10²¹ silicon atoms is

What mass of sodium nitrate would be produced from the complete reaction of 1.00 mol of lead nitrate? 2 NaCl + Pb(NO₃)₂ $\rarr$ 2 NaNO₃ + PbCl₂

The element oxygen consists of three naturally occuring isotopes: ¹⁶O, ¹⁷O, and ¹⁸O.The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes?

When 22.0 g NaCl and 21.0 g H₂SO₄ are mixed and react according to the equation below, which is the limiting reagent? 2NaCl + H₂SO₄ $\rarr$ Na₂SO₄ + 2HCl

What is the mass of 0.20 mole of C₂H₆O (ethanol)?

How many atoms are in 4.39 g of CO₂?

Balance the following equation using the smallest set of whole numbers, then add together the coefficients.Do not forget to count coefficients of one.The sum of the coefficients is _ CH₄ + _ Cl₂ $\rarr$ _ CCl₄ + _ HCl

How many grams of sulfur are there in 6.0 g of Fe₂(SO₄)₃?

Balance the following chemical equation: NH₃ + H₂SO₄ $\rarr$ (NH₄)₂SO₄

What is the theoretical yield of PI₃ if 48.0 g of I₂ are reacted with an excess of phosphorus according to the following chemical equation? 2P(s)+ 3I₂(s) $\rarr$ 2PI₃(s)

Balance the following equation using the smallest set of whole numbers, then add together the coefficients.Do not forget to count coefficients of one.The sum of the coefficients is _ Al + _ H₂SO₄ $\rarr$ _ Al₂(SO₄)₃ + _ H₂

Acetylene gas, HCCH(g), can be generated in the laboratory by adding calcium carbide to excess water, as shown in the following reaction CaC₂(s)+ H₂O(l) $\rarr$ HCCH(g)+ CaO(s) How many grams of CaC₂ would be required to generate 0.20 moles of HCCH(g)?