Question 1

The average atomic mass of B is 10.80 u. Boron has only two stable forms   (10.00 u) and   (11.00 u). What is the natural percent abundance of   ?

Accepted Answer

A)  80% 
B)  20% 
C)  1.0% 
D)  3.8% 
E)  75% 
A)  80% 
B)  20% 
C)  1.0% 
D)  3.8% 
E)  75%

Question 2

A sample of pure carbon weighing 1.48 g was burned in an excess of air. The mass of carbon dioxide, the sole product, was 5.42 g. In a second experiment, 11.62 g of carbon dioxide was obtained. What mass of carbon was burned in the second experiment?

Accepted Answer

A)  42.6 g 
B)  3.17 g 
C)  3.54 g 
D)  0.866 g 
E)  11.6 g 
A)  42.6 g 
B)  3.17 g 
C)  3.54 g 
D)  0.866 g 
E)  11.6 g

Question 3

A hypothetical element, E, has two stable isotopes: E-46 = 46.046 u 64.08% E-51 = 50.826 u 35.92%
What is the average atom weight of the element?

Accepted Answer

A)  47.76 u 
B)  48.44 u 
C)  49.11 u 
D)  48.50 u 
E)  47.44 u 
A)  47.76 u 
B)  48.44 u 
C)  49.11 u 
D)  48.50 u 
E)  47.44 u

Question 4

An element has 5 stable isotopes. The mass and percentage of each are: 89.9043 51.46%
90)9053 11.23%
91)9046 17.11%
93)9061 17.40%
95)9082 2.80%
The element is which of the following?

Accepted Answer

A)  Nb 
B)  Y 
C)  Sr 
D)  Zr 
E)  Rb 
A)  Nb 
B)  Y 
C)  Sr 
D)  Zr 
E)  Rb

Question 5

What is the mass number of the most abundant form of oxygen atom?

Accepted Answer

A)  15.9994 
B)  8 
C)  16 
D)  24 
E)  32 
A)  15.9994 
B)  8 
C)  16 
D)  24 
E)  32

Question 6

When a chemical reaction is carried out in a sealed container, the substances may change in color, temperature, or state, but no change in mass is detected. This is evidence of the:

Accepted Answer

A)  law of conservation of mass 
B)  law of constant composition 
C)  law of definite proportions 
D)  existence of electrons 
E)  existence of protons 
A)  law of conservation of mass 
B)  law of constant composition 
C)  law of definite proportions 
D)  existence of electrons 
E)  existence of protons

Question 7

A cubic centimeter of lead weighs 11.35 g. How many atoms are in the block?

Accepted Answer

A)  6.8 × 1024 atoms 
B)  2.4 × 1023 atoms 
C)  3.3 × 1022 atoms 
D)  5.3 × 1022 atoms 
E)  1.1 × 1025 atoms 
A)  6.8 × 1024 atoms 
B)  2.4 × 1023 atoms 
C)  3.3 × 1022 atoms 
D)  5.3 × 1022 atoms 
E)  1.1 × 1025 atoms

Question 8

A 1.4 g sample of calcium is reacted with 3.2 g of oxygen. The only product after the reaction is 1.96 g of CaO. How many grams of oxygen remains unreacted?

Accepted Answer

A)  0.56 g 
B)  0.224 g 
C)  2.64 g 
D)  0.264 g 
E)  0.203 g 
A)  0.56 g 
B)  0.224 g 
C)  2.64 g 
D)  0.264 g 
E)  0.203 g

Question 9

Which of these atoms has the greatest number of neutrons in its nucleus?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 10

Main group elements are those in groups ________.

Accepted Answer

A)  1 and 2 
B)  1, 2, and 13 to 18 
C)  13 to 18 
D)  1 and 18 
E)  3 to 12 
A)  1 and 2 
B)  1, 2, and 13 to 18 
C)  13 to 18 
D)  1 and 18 
E)  3 to 12

Question 11

What is the proper   notation for an ion having 35 protons, 36 electrons and 45 neutrons?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 12

How many arsenic atoms are in 5.21 g of arsenic?

Accepted Answer

A)  0.0695 atoms 
B)  9.51 × 1022 atoms 
C)  3.14 × 1024 atoms 
D)  2.10 × 1022 atoms 
E)  4.19 × 1022 atoms 
A)  0.0695 atoms 
B)  9.51 × 1022 atoms 
C)  3.14 × 1024 atoms 
D)  2.10 × 1022 atoms 
E)  4.19 × 1022 atoms

Question 13

Rubidium possesses two stable forms and has an average mass of 85.5. 85Rb has a mass of 84.9 and a percent abundance of 72.2%. What is the mass of the other form of Rb?

Accepted Answer

A)  86.1 u 
B)  85.7 u 
C)  88.3 u 
D)  87.1 u 
E)  89.4 u 
A)  86.1 u 
B)  85.7 u 
C)  88.3 u 
D)  87.1 u 
E)  89.4 u

Question 14

Write the symbol for the radioactive isotope phosphorus-32.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 15

Atoms combine in small, whole-numbered ratios.

Accepted Answer

A) True 
 B)False

Question 16

A new element is discovered. It has two isotopes. The relative abundance of the isotopes and their masses are 18% isotope 1, mass 350.0 u and 82% isotope 2, mass 352.0 u. What is the atomic mass of the element?

Accepted Answer

A)  351.6 
B)  351.0 
C)  350.4 
D)  352.0 
E)  350.0 
A)  351.6 
B)  351.0 
C)  350.4 
D)  352.0 
E)  350.0

Question 17

A cation has 28 neutrons and 21 electrons. If it has a +3 charge, what is its correct symbol?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 18

Silver possesses two stable isotopes: 107Ag (106.90 u) and 109Ag (108.90 u). If the average atomic mass of Ag is 107.87 u, what is the percent abundance of 107Ag?

Accepted Answer

A)  48.5% 
B)  50.0% 
C)  51.5% 
D)  46.3% 
E)  53.8% 
A)  48.5% 
B)  50.0% 
C)  51.5% 
D)  46.3% 
E)  53.8%

Question 19

What is the thickness in mm of the sheet 75.0 cm × 35.0 cm formed by 7.88 × 1023 atoms of lead? The density of lead is 11.35 g/cm3.

Accepted Answer

A)  9.10 
B)  0.0910 
C)  1.88 × 104 
D)  0.273 
E)  2.73 
A)  9.10 
B)  0.0910 
C)  1.88 × 104 
D)  0.273 
E)  2.73

Question 20

A solution contains 12.5% NaCl by mass. What mass of solution is required to obtain 1.0 × 1023 Na atoms?

Accepted Answer

A)  0.013 g 
B)  30 g 
C)  1.2 g 
D)  95 g 
E)  78 g 
A)  0.013 g 
B)  30 g 
C)  1.2 g 
D)  95 g 
E)  78 g

Exam 2: Atoms and the Atomic Theory

The average atomic mass of B is 10.80 u. Boron has only two stable forms (10.00 u) and (11.00 u). What is the natural percent abundance of ?

A sample of pure carbon weighing 1.48 g was burned in an excess of air. The mass of carbon dioxide, the sole product, was 5.42 g. In a second experiment, 11.62 g of carbon dioxide was obtained. What mass of carbon was burned in the second experiment?

A hypothetical element, E, has two stable isotopes: E-46 = 46.046 u 64.08% E-51 = 50.826 u 35.92% What is the average atom weight of the element?

An element has 5 stable isotopes. The mass and percentage of each are: 89.9043 51.46% 90)9053 11.23% 91)9046 17.11% 93)9061 17.40% 95)9082 2.80% The element is which of the following?

What is the mass number of the most abundant form of oxygen atom?

When a chemical reaction is carried out in a sealed container, the substances may change in color, temperature, or state, but no change in mass is detected. This is evidence of the:

A cubic centimeter of lead weighs 11.35 g. How many atoms are in the block?

A 1.4 g sample of calcium is reacted with 3.2 g of oxygen. The only product after the reaction is 1.96 g of CaO. How many grams of oxygen remains unreacted?

Which of these atoms has the greatest number of neutrons in its nucleus?

Main group elements are those in groups ________.

What is the proper notation for an ion having 35 protons, 36 electrons and 45 neutrons?

How many arsenic atoms are in 5.21 g of arsenic?

Rubidium possesses two stable forms and has an average mass of 85.5. 85Rb has a mass of 84.9 and a percent abundance of 72.2%. What is the mass of the other form of Rb?

Write the symbol for the radioactive isotope phosphorus-32.

Atoms combine in small, whole-numbered ratios.

A new element is discovered. It has two isotopes. The relative abundance of the isotopes and their masses are 18% isotope 1, mass 350.0 u and 82% isotope 2, mass 352.0 u. What is the atomic mass of the element?

A cation has 28 neutrons and 21 electrons. If it has a +3 charge, what is its correct symbol?

Silver possesses two stable isotopes: 107Ag (106.90 u) and 109Ag (108.90 u). If the average atomic mass of Ag is 107.87 u, what is the percent abundance of 107Ag?

What is the thickness in mm of the sheet 75.0 cm × 35.0 cm formed by 7.88 × 1023 atoms of lead? The density of lead is 11.35 g/cm3.

A solution contains 12.5% NaCl by mass. What mass of solution is required to obtain 1.0 × 1023 Na atoms?

Matter - Its Properties and Measurement

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Additional Aspects

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Chemical Kinetics

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

Electrochemistry

Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry 1-41

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

What is the thickness in mm of the sheet 75.0 cm × 35.0 cm formed by 7.88 × 10²³ atoms of lead? The density of lead is 11.35 g/cm3.

A solution contains 12.5% NaCl by mass. What mass of solution is required to obtain 1.0 × 10²³ Na atoms?