Question 1

Which bond or interaction would be difficult to disrupt when compounds are put into water?

Accepted Answer

A) covalent bond 
B) hydrogen bond 
C) van der Waals interaction 
D) ionic bond 
E) either covalent bonds or ionic bonds

Question 2

-What causes the shape of the molecule shown above?

Accepted Answer

A) the configuration of the 2 p orbitals in the carbon atom 
B) the configuration of the 1 s orbital in the carbon atom 
C) the configuration of the sp hybrid orbitals of the electrons shared between the carbon and hydrogen atoms 
D) the packing of the carbon and hydrogen atoms in a crystal lattice 
E) hydrogen bonding configurations between the carbon and hydrogen atoms

Question 3

Why is each element unique and different from other elements in chemical properties?

Accepted Answer

A) Each element has a unique atomic mass. 
B) Each element has a unique atomic weight. 
C) Each element has a unique number of protons in its nucleus. 
D) Each element has a unique number of neutrons in its nucleus. 
E) Each element has different radioactive properties.

Question 4

Which of the following correctly describes chemical equilibrium?

Accepted Answer

A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products. 
B) Concentrations of products are higher than the concentrations of the reactants. 
C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products. 
D) Reactions stop only when all reactants have been converted to products. 
E) There are equal concentrations of reactants and products, and the reactions have stopped.

Question 5

A covalent bond is likely to be polar when

Accepted Answer

A) one of the atoms sharing electrons is much more electronegative than the other atom. 
B) the two atoms sharing electrons are equally electronegative. 
C) oxygen is one of the two atoms sharing electrons. 
D) one of the atoms has absorbed more energy than the other atom. 
E) the two atoms sharing electrons are different elements.

Question 6

The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?

Accepted Answer

A) It has 8 electrons in its outer electron shell. 
B) It is inert. 
C) It has an atomic mass of 10 daltons. 
D) It has 8 electrons in its outer electron shell and it is inert. 
E) It has 8 electrons in its outer electron shell, it is inert, and it has an atomic mass of 10 daltons.

Question 7

were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed?

Accepted Answer

A) S-H 
B) H-S-H 
C)   
D)   
E)

Question 8

Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why?

Accepted Answer

A) The atomic mass does not include the mass of electrons. 
B) Some carbon atoms in nature have an extra proton. 
C) Some carbon atoms in nature have more neutrons. 
D) Some carbon atoms in nature have a different valence electron distribution. 
E) Some carbon atoms in nature have undergone radioactive decay.

Question 9

Use the following figure to answer the questions below.
 
-In the figure above, how many electrons does nitrogen have in its valence shell?

Accepted Answer

A) 2 
B) 5 
C) 7 
D) 8 
E) 14

Question 10

The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?

Accepted Answer

A) MgCl 
B) MgCl₂ 
C) Mg₂Cl 
D) Mg₂Cl₂ 
E) MgCl₃

Question 11

Use the following information to answer the questions below.
You are investigating how chemical reactions occur. You place two reactants together and measure the concentration of product at regular intervals. After a time, the amount of product becomes stable.
-Which of the following statements correctly describes any chemical reaction that has reached equilibrium?

Accepted Answer

A) The concentrations of products and reactants are equal. 
B) The reaction is now irreversible. 
C) Both forward and reverse reactions have halted. 
D) The rates of the forward and reverse reactions are equal. 
E) No reactants remain.

Question 12

In what way are elements in the same column of the periodic table the same?

Accepted Answer

A) They have the same number of protons. 
B) They have the same number of neutrons. 
C) They have the same number of electrons. 
D) They have the same number of electrons in their valence shell. 
E) They have the same number of electron shells.

Question 13

A group of molecular biologists is trying to synthesize a new artificial compound to mimic the effects of a known hormone that influences sexual behaviour. They have turned to you for advice. Which of the following compounds is most likely to mimic the effects of the hormone?

Accepted Answer

A) a compound with the same number of carbon atoms as the hormone 
B) a compound with the same molecular mass (measured in daltons)as the hormone 
C) a compound with the same three-dimensional shape as part of the hormone 
D) a compound with the same number of orbital electrons as the hormone 
E) a compound with the same number of hydrogen and nitrogen atoms as the hormone

Question 14

Which one of the atoms shown would be most likely to form an anion with a charge of -1?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 15

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?

Accepted Answer

A) nitrogen 
B) calcium 
C) iodine 
D) sodium 
E) phosphorus

Question 16

Use the following information to answer the questions below.
You are investigating how chemical reactions occur. You place two reactants together and measure the concentration of product at regular intervals. After a time, the amount of product becomes stable.
-Which statement is true of all atoms that are anions?

Accepted Answer

A) The atom has more electrons than protons. 
B) The atom has more protons than electrons. 
C) The atom has fewer protons than does a neutral atom of the same element. 
D) The atom has more neutrons than protons. 
E) The net charge is 1-.

Question 17

The precise weight of a mole of some pure elements like silicon (Si)can vary slightly from the standard atomic mass, or even from sample to sample. Why?

Accepted Answer

A) The element may undergo radioactive decay. 
B) The element may react with itself and gain or lose subatomic particles. 
C) The atoms of the element form chemical bonds with each other, and that changes the weight of the element. 
D) The element may have multiple stable isotopes, and the isotopic composition may vary from sample to sample. 
E) The amount of energy absorbed by the element affects the mass of its electrons, and thus the atomic mass can vary slightly.

Question 18

What results from an unequal sharing of electrons between atoms?

Accepted Answer

A) a nonpolar covalent bond 
B) a polar covalent bond 
C) an ionic bond 
D) a hydrogen bond 
E) a hydrophobic interaction

Question 19

Which of the following pairs of atoms would be most likely to form an ionic bond?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 20

Use the following figure to answer the questions below.
 
-Which drawing in the figure above depicts the electron configuration of an atom capable of forming three covalent bonds with other atoms?

Accepted Answer

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

Exam 2: The Chemical Context of Life