Question 1

The system of atomic mass units is based on

Accepted Answer

A)  assigning 12C as weighing exactly 12 u & comparing other elements to it.
B)  measuring the true mass of each subatomic particle.
C)  comparing the differences in protons and electrons.
D)  viewing how atoms are affected by electromagnetic fields.E) A) and D)
F) A) and C)

Question 2

How many moles of hydrogen molecules (H2) would be required to produce two moles of hydrogen peroxide (H2O2) ?

Accepted Answer

A)  1
B)  2
C)  3
D)  4E) None of the above
F) A) and C)

Question 3

Which of the following uses the unit of "u" or "amu"?

Accepted Answer

A)  atomic weights of atoms
B)  relative masses of atoms
C)  molecular weights of molecules
D)  more than one response is correctE) A) and B)
F) None of the above

Question 4

An isotope of a given element has a mass number equal to twice the atomic number.  This neutral isotope contains twelve electrons.  This isotope is _____ .

Accepted Answer

A)  magnesium-12.
B)  magnesium-24.
C)  chromium-24.
D)  chromium-12.E) A) and B)
F) A) and C)

Question 5

What is meant when the symbol C-12 (or 12C) is used?

Accepted Answer

A)  the carbon atom weighs 12 grams
B)  the carbon atom weighs 12 pounds
C)  the carbon atom weighs 12 amu
D)  the melting point of carbon is 12°CE) All of the above
F) A) and B)

Question 6

The pure substance, water, contains both hydrogen molecules and oxygen molecules.

Accepted Answer

A) True 
 B)False

Question 7

How many carbon atoms are contained in 5.50 g of ethane, C2H6?

Accepted Answer

A)  2.75 × 10 − 22
B)  3.29 × 1024
C)  1.10 × 1023
D)  2.21 × 1023E) B) and D)
F) All of the above

Question 8

​ Why are the atomic weights of elements defined as the relative masses of average atoms of the elements?

Accepted Answer

​ The mass number of an isotope is the sum of the number of protons and neutrons in the nucleus of the atoms of the isotope. Also, both protons and neutrons have masses of 1 u. Since the masses of electrons are quite small, the atomic weights of isotopes are almost equal to their mass numbers. Therefore, the atomic weights of elements can be defined as the relative masses of average atoms of the elements.

Question 9

One mole of H2O contains 2.0 grams of hydrogen.

Accepted Answer

A) True 
 B)False

Question 10

An MRI instrument cause the hydrogens in your body to line up because they are exposed to a very strong magnetic field.

Accepted Answer

A) True 
 B)False

Question 11

The weight % of S in K2SO4 is _____ .

Accepted Answer

A)  14.2%
B)  18.4%
C)  54.4%
D)  22.4%E) A) and B)
F) C) and D)

Question 12

What is the number of hydrogen atoms in a 18.016 gram sample of water?

Accepted Answer

A)  2.000
B)  6.022 × 1023
C)  18.02
D)  1.204 × 1024E) A) and C)
F) A) and D) D

Question 13

H2O2 contains equal parts by weight of hydrogen and oxygen.

Accepted Answer

A) True 
 B)False

Question 14

How many electrons are in a neutral atom of carbon-13 (13C) ?

Accepted Answer

A)  6
B)  18
C)  12
D)  no way to tellE) C) and D)
F) B) and C)

Question 15

What is the molar mass of Ba3(PO4) 2?

Accepted Answer

A)  232.30 g\mol
B)  327.27 g\mol
C)  369.63 g\mol
D)  601.92 g\molE) A) and C)
F) All of the above D

Question 16

Determine the number of electrons and protons in the element Tc.

Accepted Answer

A)  43 protons, 43 electrons
B)  43 protons, 56 electrons
C)  56 protons, 43 electrons
D)  99 protons, 43 electronsE) A) and B)
F) A) and C)

Question 17

How many neutrons are found in the nucleus of a boron-11 (11B) atom?

Accepted Answer

A)  11
B)  6
C)  5
D)  4E) All of the above
F) B) and D)

Question 18

The _____ _____ of an atom is the number equal to the number of protons in the nucleus of an atom and is represented by Z.

Accepted Answer

A)  neutron number
B)  mass number
C)  Mass number
D)  atomic numberE) A) and D)
F) C) and D)

Question 19

What is the meaning of the two (2) in ethyl alcohol, C2H5OH?

Accepted Answer

A)  all alcohol molecules contain two carbon atoms
B)  there are two carbon atoms per molecule of ethyl alcohol
C)  carbon is diatomic
D)  all of these are correct statementsE) A) and B)
F) B) and C)

Question 20

Determine the molecular weight of hydrogen peroxide, H2O2, in u (or amu) .

Accepted Answer

A)  17.01
B)  18.02
C)  34.02
D)  33.01E) C) and D)
F) B) and D)

Exam 2: Atoms and Molecules

The system of atomic mass units is based on

Correct Answer
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How many moles of hydrogen molecules (H₂) would be required to produce two moles of hydrogen peroxide (H₂O₂) ?

Correct Answer
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Which of the following uses the unit of "u" or "amu"?

Correct Answer
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An isotope of a given element has a mass number equal to twice the atomic number. This neutral isotope contains twelve electrons. This isotope is _____ .

Correct Answer
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What is meant when the symbol C-12 (or ¹²C) is used?

Correct Answer
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The pure substance, water, contains both hydrogen molecules and oxygen molecules.

Correct Answer
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How many carbon atoms are contained in 5.50 g of ethane, C₂H₆?

Correct Answer
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Why are the atomic weights of elements defined as the relative masses of average atoms of the elements?

One mole of H₂O contains 2.0 grams of hydrogen.

Correct Answer
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An MRI instrument cause the hydrogens in your body to line up because they are exposed to a very strong magnetic field.

Correct Answer
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The weight % of S in K₂SO₄ is _____ .

Correct Answer
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What is the number of hydrogen atoms in a 18.016 gram sample of water?

Correct Answer
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D

H₂O₂ contains equal parts by weight of hydrogen and oxygen.

Correct Answer
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How many electrons are in a neutral atom of carbon-13 (¹³C) ?

Correct Answer
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What is the molar mass of Ba₃(PO₄) ₂?

Correct Answer
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D

Determine the number of electrons and protons in the element Tc.

Correct Answer
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How many neutrons are found in the nucleus of a boron-11 (¹¹B) atom?

Correct Answer
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The _ _ of an atom is the number equal to the number of protons in the nucleus of an atom and is represented by Z.

Correct Answer
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What is the meaning of the two (2) in ethyl alcohol, C₂H₅OH?

Correct Answer
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Determine the molecular weight of hydrogen peroxide, H₂O₂, in u (or amu) .

Correct Answer
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Exam 2: Atoms and Molecules

The system of atomic mass units is based on

Correct AnswerverifiedShow Answer

How many moles of hydrogen molecules (H2) would be required to produce two moles of hydrogen peroxide (H2O2) ?

Correct AnswerverifiedShow Answer

Which of the following uses the unit of "u" or "amu"?

Correct AnswerverifiedShow Answer

An isotope of a given element has a mass number equal to twice the atomic number. This neutral isotope contains twelve electrons. This isotope is _____ .

Correct AnswerverifiedShow Answer

What is meant when the symbol C-12 (or 12C) is used?

Correct AnswerverifiedShow Answer

The pure substance, water, contains both hydrogen molecules and oxygen molecules.

Correct AnswerverifiedShow Answer

How many carbon atoms are contained in 5.50 g of ethane, C2H6?

Correct AnswerverifiedShow Answer

​ Why are the atomic weights of elements defined as the relative masses of average atoms of the elements?

One mole of H2O contains 2.0 grams of hydrogen.

Correct AnswerverifiedShow Answer

An MRI instrument cause the hydrogens in your body to line up because they are exposed to a very strong magnetic field.

Correct AnswerverifiedShow Answer

The weight % of S in K2SO4 is _____ .

Correct AnswerverifiedShow Answer

What is the number of hydrogen atoms in a 18.016 gram sample of water?

Correct AnswerverifiedD

H2O2 contains equal parts by weight of hydrogen and oxygen.

Correct AnswerverifiedShow Answer

How many electrons are in a neutral atom of carbon-13 (13C) ?

Correct AnswerverifiedShow Answer

What is the molar mass of Ba3(PO4) 2?

Correct AnswerverifiedD

Determine the number of electrons and protons in the element Tc.

Correct AnswerverifiedShow Answer

How many neutrons are found in the nucleus of a boron-11 (11B) atom?

Correct AnswerverifiedShow Answer

The _____ _____ of an atom is the number equal to the number of protons in the nucleus of an atom and is represented by Z.

Correct AnswerverifiedShow Answer

What is the meaning of the two (2) in ethyl alcohol, C2H5OH?

Correct AnswerverifiedShow Answer

Determine the molecular weight of hydrogen peroxide, H2O2, in u (or amu) .

Correct AnswerverifiedShow Answer

Correct Answer
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How many moles of hydrogen molecules (H₂) would be required to produce two moles of hydrogen peroxide (H₂O₂) ?

Correct Answer
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Correct Answer
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Correct Answer
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What is meant when the symbol C-12 (or ¹²C) is used?

Correct Answer
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Correct Answer
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How many carbon atoms are contained in 5.50 g of ethane, C₂H₆?

Correct Answer
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Why are the atomic weights of elements defined as the relative masses of average atoms of the elements?

One mole of H₂O contains 2.0 grams of hydrogen.

Correct Answer
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Correct Answer
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The weight % of S in K₂SO₄ is _____ .

Correct Answer
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Correct Answer
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D

H₂O₂ contains equal parts by weight of hydrogen and oxygen.

Correct Answer
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How many electrons are in a neutral atom of carbon-13 (¹³C) ?

Correct Answer
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What is the molar mass of Ba₃(PO₄) ₂?

Correct Answer
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D

Correct Answer
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How many neutrons are found in the nucleus of a boron-11 (¹¹B) atom?

Correct Answer
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The _ _ of an atom is the number equal to the number of protons in the nucleus of an atom and is represented by Z.

Correct Answer
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What is the meaning of the two (2) in ethyl alcohol, C₂H₅OH?

Correct Answer
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Determine the molecular weight of hydrogen peroxide, H₂O₂, in u (or amu) .

Correct Answer
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