Question 1

How many Mg atoms are present in 170 g of Mg?

Accepted Answer

The answer of How many Mg atoms are present in...

Question 2

Calculate the mass of sodium chlorate that must decompose to form 6.5 g of oxygen.
2NaClO3(s)$\rarr$ 2NaCl(s)+ 3O2(g)

Accepted Answer

Question 3

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 4

A sample of unknown ore was analyzed and found to contain 12.7% Al, 19.7% N, and 67.6% O.What is the empirical formula of this ore?

Accepted Answer

The answer of A sample of unknown ore was analyzed...

Question 5

How many Br atoms are in 2.50 g of Br?

Accepted Answer

A) 1.88x1022 Br atoms 
B) 1.51 x 1024 Br atoms 
C) 7.54 x 1021 Br atoms 
D) 6.02 x 1023 Br atoms 
E) 9.42 x 1021 Br atoms 
A) 1.88x1022 Br atoms 
B) 1.51 x 1024 Br atoms 
C) 7.54 x 1021 Br atoms 
D) 6.02 x 1023 Br atoms 
E) 9.42 x 1021 Br atoms

Question 6

How many moles of H are in 4.56 moles of NH2NH2?

Accepted Answer

A) 4.52 moles H 
B) 4.56 moles H 
C) 9.12 moles H 
D) 18.39 moles H 
E) 18.24 moles H 
A) 4.52 moles H 
B) 4.56 moles H 
C) 9.12 moles H 
D) 18.39 moles H 
E) 18.24 moles H

Question 7

The Hall process for the production of aluminum involves the reaction of aluminum oxide with elemental carbon to give aluminum metal and carbon monoxide.If the percent yield of this reaction is 82% and aluminum ore is 71% by mass aluminum oxide, what mass of aluminum ore must be mined in order to produce 1.0 × 103 kg (1 metric ton)of aluminum metal by the Hall process?

Accepted Answer

A) 1.1 × 103 kg 
B) 1.6 × 103 kg 
C) 1.8 × 103 kg 
D) 2.2 × 103 kg 
E) 3.3 × 103 kg 
A) 1.1 × 103 kg 
B) 1.6 × 103 kg 
C) 1.8 × 103 kg 
D) 2.2 × 103 kg 
E) 3.3 × 103 kg

Question 8

Liquid hexane, C6H14, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 10.0 mL of hexane? (density of hexane = 0.660 g/mL)

Accepted Answer

A) 2.45 g 
B) 3.71 g 
C) 23.3 g 
D) 35.3 g 
E) 46.6 g 
A) 2.45 g 
B) 3.71 g 
C) 23.3 g 
D) 35.3 g 
E) 46.6 g

Question 9

What is the theoretical yield of vanadium that can be produced by the reaction of 40.0 g of V2O5 with 40.0 g of calcium based on the following chemical reaction? V2O5(s)+ 5Ca(l)$\rarr$ 2V(l)+ 5CaO(s)

Accepted Answer

A) 5.6 g 
B) 11.2 
C) 20.3 g 
D) 22.4 g 
E) 40.0 g 
A) 5.6 g 
B) 11.2 
C) 20.3 g 
D) 22.4 g 
E) 40.0 g

Question 10

When a 0.952 g sample of an organic compound containing C, H, and O is burned completely in oxygen, 1.35 g of CO2 and 0.826 g of H2O are produced.What is the empirical formula of the compound?

Accepted Answer

Question 11

An unknown compound with a molar mass of 223.94 g/mol consists of 32.18% C, 4.50% H, and 63.32% Cl.Find the molecular formula for the compound.

Accepted Answer

A) CHCl 
B) C6H10Cl4 
C) C3H5Cl2 
D) C9H15Cl6 
E) C6H10Cl2 
A) CHCl 
B) C6H10Cl4 
C) C3H5Cl2 
D) C9H15Cl6 
E) C6H10Cl2

Question 12

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 13

Liquid heptane, C7H16, burns in oxygen gas to yield carbon dioxide and water.What mass of water is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Accepted Answer

A) 1.85 g 
B) 2.70 g 
C) 14.8 g 
D) 21.6 g 
E) 31.6 g 
A) 1.85 g 
B) 2.70 g 
C) 14.8 g 
D) 21.6 g 
E) 31.6 g

Question 14

Pressurized metal gas cylinders are generally used to store commonly used gases in the laboratory.At times, it can be easier to chemically prepare occasionally used gases..For example, nitrogen monoxide, NO(g), can be prepared in the lab by the following chemical reaction:
3Cu(s)+ 8HNO3(aq)$\rarr$2NO(g)+ 3Cu(NO3)2(aq)+ 4H2O(l)
If 15 g of copper metal was added to an aqueous solution containing 6.0 moles of HNO3, how many moles of NO(g)would be produced, assuming a 75% yield.

Accepted Answer

Question 15

How many grams of Cl2 can be prepared from the reaction of 16.0 g of MnO2 and 30.0 g of HCl according to the following chemical equation? 
MnO2 + 4HCl $\rarr$MnCl2 + Cl2 + 2H2O

Accepted Answer

A) 0.82 g 
B) 5.8 g 
C) 13.0 g 
D) 14.6 g 
E) 58.4 g 
A) 0.82 g 
B) 5.8 g 
C) 13.0 g 
D) 14.6 g 
E) 58.4 g

Question 16

How many sulfur atoms are present in 25.6 g of Al2(S2O3)3?

Accepted Answer

A) 0.393 
B) 6.00 
C) 3.95 × 1022 
D) 7.90 × 1022 
E) 2.37 × 1023 
A) 0.393 
B) 6.00 
C) 3.95 × 1022 
D) 7.90 × 1022 
E) 2.37 × 1023

Question 17

An organic thiol compound is 38.66% C, 9.73% H, and 51.61% S by mass.What is the empirical formula of this compound?

Accepted Answer

A) C2H6S 
B) C3H8S 
C) C4H10S 
D) C4H12S 
E) C5H14S 
A) C2H6S 
B) C3H8S 
C) C4H10S 
D) C4H12S 
E) C5H14S

Question 18

A 0.8715 g sample of sorbic acid, a compound first obtained from the berries of a certain ash tree, is burned completely in oxygen to give 2.053 g of carbon dioxide and 0.5601 g of water.The empirical formula of sorbic acid is

Accepted Answer

A) CH2O 
B) C3H4O 
C) CH4O3 
D) C3H4O2 
E) C2H4O2 
A) CH2O 
B) C3H4O 
C) CH4O3 
D) C3H4O2 
E) C2H4O2

Question 19

Liquid heptane, C7H16, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane? (density of heptane = 0.6838 g/mL)

Accepted Answer

A) 5.57 g 
B) 8.14 g 
C) 30.6 g 
D) 61.3 g 
E) 89.6 g 
A) 5.57 g 
B) 8.14 g 
C) 30.6 g 
D) 61.3 g 
E) 89.6 g

Question 20

An atom of helium has a mass about four times greater than that of an atom of hydrogen.Which choice makes the correct comparison of the relative numbers of helium and hydrogen atoms in equal masses of the two elements?

Accepted Answer

A) There are about four times as many helium atoms as hydrogen atoms. 
B) There are about two times as many helium atoms as hydrogen atoms. 
C) The number of helium and hydrogen atoms is the same. 
D) There are about half as many helium atoms as hydrogen atoms. 
E) There are about one-fourth as many helium atoms as hydrogen atoms. 
A) There are about four times as many helium atoms as hydrogen atoms. 
B) There are about two times as many helium atoms as hydrogen atoms. 
C) The number of helium and hydrogen atoms is the same. 
D) There are about half as many helium atoms as hydrogen atoms. 
E) There are about one-fourth as many helium atoms as hydrogen atoms.

Exam 3: Mass Relationships in Chemical Reactions

How many Mg atoms are present in 170 g of Mg?

Calculate the mass of sodium chlorate that must decompose to form 6.5 g of oxygen. 2NaClO3(s) →\rarr→ 2NaCl(s)+ 3O2(g)

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)

A sample of unknown ore was analyzed and found to contain 12.7% Al, 19.7% N, and 67.6% O.What is the empirical formula of this ore?

How many Br atoms are in 2.50 g of Br?

How many moles of H are in 4.56 moles of NH2NH2?

Liquid hexane, C6H14, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 10.0 mL of hexane? (density of hexane = 0.660 g/mL)

What is the theoretical yield of vanadium that can be produced by the reaction of 40.0 g of V2O5 with 40.0 g of calcium based on the following chemical reaction? V2O5(s)+ 5Ca(l) →\rarr→ 2V(l)+ 5CaO(s)

When a 0.952 g sample of an organic compound containing C, H, and O is burned completely in oxygen, 1.35 g of CO2 and 0.826 g of H2O are produced.What is the empirical formula of the compound?

An unknown compound with a molar mass of 223.94 g/mol consists of 32.18% C, 4.50% H, and 63.32% Cl.Find the molecular formula for the compound.

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

Liquid heptane, C7H16, burns in oxygen gas to yield carbon dioxide and water.What mass of water is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

How many grams of Cl2 can be prepared from the reaction of 16.0 g of MnO2 and 30.0 g of HCl according to the following chemical equation? MnO2 + 4HCl →\rarr→ MnCl2 + Cl2 + 2H2O

How many sulfur atoms are present in 25.6 g of Al2(S2O3)3?

An organic thiol compound is 38.66% C, 9.73% H, and 51.61% S by mass.What is the empirical formula of this compound?

A 0.8715 g sample of sorbic acid, a compound first obtained from the berries of a certain ash tree, is burned completely in oxygen to give 2.053 g of carbon dioxide and 0.5601 g of water.The empirical formula of sorbic acid is

Liquid heptane, C7H16, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane? (density of heptane = 0.6838 g/mL)

An atom of helium has a mass about four times greater than that of an atom of hydrogen.Which choice makes the correct comparison of the relative numbers of helium and hydrogen atoms in equal masses of the two elements?

Chemistry: the Study of Change

Atoms, Molecules, and Ions

Reactions in Aqueous Solutions

Gases

Thermochemistry

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

Entropy Free Energy and Equilibrium

Electrochemistry

Nuclear Chemistry

Chemistry in the Atmosphere

Metallurgy and the Chemistry of Metals

Nonmetallic Elements and Their Compounds

Transition Metal Chemistry and Coordination Compounds

Organic Chemistry

Synthetic and Natural Organic Polymers

Filters

Calculate the mass of sodium chlorate that must decompose to form 6.5 g of oxygen. 2NaClO₃(s) $\rarr$ 2NaCl(s)+ 3O₂(g)

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)

How many moles of H are in 4.56 moles of NH₂NH₂?

Liquid hexane, C₆H₁₄, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 10.0 mL of hexane? (density of hexane = 0.660 g/mL)

What is the theoretical yield of vanadium that can be produced by the reaction of 40.0 g of V₂O₅ with 40.0 g of calcium based on the following chemical reaction? V₂O₅(s)+ 5Ca(l) $\rarr$ 2V(l)+ 5CaO(s)

When a 0.952 g sample of an organic compound containing C, H, and O is burned completely in oxygen, 1.35 g of CO₂ and 0.826 g of H₂O are produced.What is the empirical formula of the compound?

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What mass of water is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

How many grams of Cl₂ can be prepared from the reaction of 16.0 g of MnO₂ and 30.0 g of HCl according to the following chemical equation? MnO₂ + 4HCl $\rarr$ MnCl₂ + Cl₂ + 2H₂O

How many sulfur atoms are present in 25.6 g of Al₂(S₂O₃)₃?

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane? (density of heptane = 0.6838 g/mL)