Question 1

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

Question 2

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\mol 
A) 232.30 g\mol 
B) 327.27 g\mol 
C) 369.63 g\mol 
D) 601.92 g\mol D

Question 3

​ 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 4

H2O2 contains equal parts by weight of hydrogen and oxygen.

Accepted Answer

A) True 
 B)False

Question 5

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 statements 
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 statements

Question 6

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. 
A) magnesium-12. 
B) magnesium-24. 
C) chromium-24. 
D) chromium-12.

Question 7

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

Accepted Answer

A) 6 
B) 18 
C) 12 
D) no way to tell 
A) 6 
B) 18 
C) 12 
D) no way to tell

Question 8

The weight % of S in K2SO4 is _____ .

Accepted Answer

A) 14.2% 
B) 18.4% 
C) 54.4% 
D) 22.4% 
A) 14.2% 
B) 18.4% 
C) 54.4% 
D) 22.4%

Question 9

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 number 
A) neutron number 
B) mass number 
C) Mass number 
D) atomic number

Question 10

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. 
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.

Question 11

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

Accepted Answer

A) 17.01 
B) 18.02 
C) 34.02 
D) 33.01 
A) 17.01 
B) 18.02 
C) 34.02 
D) 33.01

Question 12

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

Accepted Answer

A) 11 
B) 6 
C) 5 
D) 4 
A) 11 
B) 6 
C) 5 
D) 4

Question 13

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 correct 
A) atomic weights of atoms 
B) relative masses of atoms 
C) molecular weights of molecules 
D) more than one response is correct

Question 14

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 × 1023 
A) 2.75 × 10 − 22 
B) 3.29 × 1024 
C) 1.10 × 1023 
D) 2.21 × 1023

Question 15

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 electrons 
A) 43 protons, 43 electrons 
B) 43 protons, 56 electrons 
C) 56 protons, 43 electrons 
D) 99 protons, 43 electrons

Question 16

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°C 
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°C

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

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 19

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) 4 
A) 1 
B) 2 
C) 3 
D) 4

Question 20

One mole of H2O contains 2.0 grams of hydrogen.

Accepted Answer

A) True 
 B)False

Exam 2: Atoms and Molecules

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

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

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

H2O2 contains equal parts by weight of hydrogen and oxygen.

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

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 _____ .

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

The weight % of S in K2SO4 is _____ .

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

The system of atomic mass units is based on

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

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

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

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

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

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

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

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

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

One mole of H2O contains 2.0 grams of hydrogen.

Matter, Measurements, and Calculations

Electronic Structure and the Periodic Law

Forces Between Particles

Chemical Reactions

The States of Matter

Solutions and Colloids

Reaction Rates and Equilibrium

Acids, Bases, and Salts

Radioactivity and Nuclear Processes

Organic Compounds: Alkanes

Unsaturated Hydrocarbons

Alcohols, Phenols, and Ethers

Aldehydes and Ketones

Carboxylic Acids and Esters

Amines and Amides

Carbohydrates

Lipids

Proteins

Enzymes

Nucleic Acids and Protein Synthesis

Nutrition and Energy for Life

Carbohydrate Metabolism

Lipid and Amino Acid Metabolism

Body Fluids

Filters

What is the molar mass of Ba₃(PO₄)₂?

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

H₂O₂ contains equal parts by weight of hydrogen and oxygen.

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

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

The weight % of S in K₂SO₄ is _____ .

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

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

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

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

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

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

One mole of H₂O contains 2.0 grams of hydrogen.