Chapter Two The Nature of Molecules and Properties of Water

Question 1

The volume of space around the nucleus where an electron is most likely to be found is known as which of the following?

Multiple choice question.

Energy level

Electron volume

Electron orbital

Electron shell

Reason: Electron shell is used synonymously with energy level.

Answer 1

Electron Orbital

Question 2

Different isotopes of an element behave the same way chemically not because they have the same number of
___
but because they have the same number of
____

Answer 2

neutrons, electrons

Question 3

A cation has a net ____
while an anion has a net
___ charge.

Answer 3

+ , -

Question 4

Isotopes differ in the number of
____

Answer 4

neutrons

Question 5

Regardless of their shape and position, electron orbitals can never contain more than
____ electrons

Answer 5

2

Question 6

Valence electrons and their interactions determine the
___ properties of an element

Answer 6

chemical

Question 7

In order for an electron to move to a more distal orbital which of the following must occur?

Multiple choice question.

Energy must be released.

The electron must move faster.

The atom must lose a neutron.

Energy must be added.

Answer 7

Energy must be added

Question 8

Choose all statements that describe atoms that have unfilled electron shells?

Multiple select question.

They can form chemical compounds.

They can form bonds with other atoms

They are chemically reactive.

They are located in the far-right column of the periodic table.

They are chemically inert.

Answer 8

Chemically reactive, form chemical compounds, form bonds with other atoms

Question 9

Atoms are chemically the most stable when which of the following occurs?

Multiple choice question.

Neutrons and electrons are in equal numbers.

They reside in the middle of the periodic table.

They have six electrons in their outermost shell.

Their outer shell is full.

Answer 9

their outer shell is full.

Question 10

Different isotopes of an element behave the same way chemically because they have the same Blank______.

Multiple choice question.

number of electrons

number of neutrons

overall charge

atomic mass

Answer 10

number of electrons, neutrons are what changes.

Question 11

The atomic number of an element refers to the number of Blank______ in the atoms of that element.

Multiple choice question.

protons

orbitals

neutrons

electrons

Answer 11

protons

Question 12

Atoms of different chemical elements can be differentiated based on the number of Blank______.

Multiple choice question.

protons in the nucleus

electrons in all shells

orbitals in the outermost shell

electrons in the outermost shell

neutrons in the nucleus

Answer 12

protons in the nucleus

Question 13

Elements possessing all eight electrons (two for helium) in their outer energy level are Blank______.

Multiple select question.

noble gases

highly reactive

radioactive

inert

isotopes

Answer 13

noble gasses, inert

Question 14

A substance that cannot be broken down into simpler substances by ordinary chemical means is called a(n)

Answer 14

element

Question 15

Which subatomic particles determine the atomic mass of an atom?

Multiple choice question.

Neutrons only

Protons and electrons

Protons only

Protons and neutrons

Answer 15

protons and neutrons

Question 16

Almost all the mass of an atom is located in the

Answer 16

nucleus

Question 17

How are ions formed?

Multiple choice question.

Ions are formed when atoms lose or gain one or more neutrons.

incorrect

Ions are formed when atoms lose or gain one or more protons.

Ions are formed when atoms lose or gain one or more electrons.

Answer 17

Ions are formed when atoms lose or gain one or more electrons.

Question 18

Which of the following are some possible harmful effects of radioactive isotopes in cells?

Multiple select question.

They can disrupt metabolism, because they have different chemical properties due to their radioactivity.

They can produce genetic mutations.

They can significantly raise the temperature due to their radioactivity.

They can lead to cell death in high doses.

Answer 18

genetic mutations, cell death

Question 19

The chemical behavior of an atom is determined by the number and configuration of its

Answer 19

electrons

Question 20

Atoms, in which the number of electrons does not equal the number of protons, are called

Answer 20

ions

Question 21

Chemical reactions that involve a transfer of electrons from one atom to another are called

Answer 21

redox

Question 22

Elements, such as zinc and iodine, which are found in very small amounts in living things, but play crucial roles in biological processes, are known as which of the following?

Multiple choice question.

Trace elements

Essential elements

Inorganic elements

Answer 22

trace elements

Question 23

Arrange the following states of water in order from most dense to least dense (start with most dense at the top).

Gas
Liquid
Solid

Answer 23

Liquid
Solid
Gas

Question 24

When NaCl is formed, Blank______.

Multiple choice question.

a sodium and a chlorine atom both gain an electron

a sodium atom loses an electron, while a chlorine atom gains an electron

a chlorine atom loses an electron, while a sodium atom gains an electron

a sodium and a chlorine atom both lose an electron

Answer 24

a sodium atom loses an electron, while a chlorine atom gains an electron

Question 25

True, discrete molecules form when atoms are connected by Blank______. Multiple choice question. either covalent or ionic bonds covalent bonds hydrogen bonds ionic bonds

Answer 25

Covalent Bonds

Question 26

Which of the following statements about nonpolar molecules are true? Multiple select question. They have regions of partial positive charge and regions of partial negative charge. Some can form hydrogen bonds with polar molecules. The distribution of electrical charge is uniform. They are electrically neutral.

Answer 26

Electrically neutral, and electrical charge is uniform

Question 27

____ bond is formed by when one or more electron pairs are unequally shared between two atoms.

Answer 27

polar

Question 28

The attraction of water to other polar substances is called

Answer 28

adhesion

Question 29

Which of the following explains why water rises inside a capillary glass tube? Multiple choice question. Water molecules are repelled from the glass surface, which forces them up the tube. Water molecules adhere to the surface of the glass. Liquid water is less dense than glass. Liquid water and glass have approximately the same density. Water expands as the pressure inside the tube is reduced.

Answer 29

Water molecules adhere to the surface of the glass.

Question 30

It takes a large amount of heat energy to break ____ bonds between water molecules; this explains why water has a very ___ heat of vaporization.

Answer 30

hydrogen, high

Question 31

Water tends to repel or exclude ___ molecules.

Answer 31

nonpolar

Question 32

Hydrophobic exclusion refers to which of the following? Multiple choice question. The tendency of non-polar molecules to arrange in a way that maximizes the disruption of hydrogen bonds between water molecules The tendency of water molecules to disrupt aggregates between non-polar molecules The tendency of non-polar molecules to clump together in water

Answer 32

The tendency of non-polar molecules to clump together in water

Question 33

Unlike ____ bonds, which produce a crystal lattice, covalent ____ bonds are formed between 2 individual atoms, giving rise to true, discrete molecules.

Answer 33

ionic, covalent

Question 34

True, discrete molecules form when atoms are connected by

Answer 34

covalent bonds

Question 35

Which of the following molecules are nonpolar? Multiple select question. N2 CH4 O2 H2

Answer 35

N2, CH4 (C-H bonds are nonpolar ), O2c

Question 36

Which of the following statements about polar molecules are true? Multiple select question. The distribution of electrical charge is not uniform. They are electrically neutral. They have the same number of protons and electrons. They have regions of partial positive charge or regions of partial negative charge, but not both.

Answer 36

They have the same number of protons and electrons. They are electrically neutral. The distribution of electrical charge is not uniform.

Question 37

A solution of a stronger acid will have a higher concentration of Blank______ ions and a lower concentration of Blank______ ions. Multiple choice question. H+; OH- OH-; H+ Cl-; Na+ Na+; Cl-

Answer 37

H* , OH-

Question 38

The stronger a base is, the Blank______ its concentration of hydrogen ions and the Blank______ its pH. Multiple choice question. higher; lower lower; lower lower; higher higher; higher

Answer 38

lower : higher

Question 39

A(n) ___ covalent bond involves an equal sharing of one or more pairs of electrons.

Answer 39

nonpolar

Question 40

The evaporation of water from body surfaces can significantly cool an organism. This is due to what property of water? Multiple choice question. The lower density of ice Water's high heat of vaporization Water's cohesive properties Water's solubility

Answer 40

Water's high heat of vaporization

Question 41

Select the polar molecule. Multiple choice question. CH4 Reason: Although C and H differ slightly in electronegativity, the difference is negligible and C-H bonds are considered nonpolar. O2 H2O H2

Answer 41

H2O

Question 42

__ covalent bond is formed by when one or more electron pairs are unequally shared between two atoms.

Answer 42

polar

Question 43

Why is solid water less dense than liquid water? Multiple choice question. As the movement of water molecules speeds up when liquid water changes to ice, hydrogen bonds form that space the molecules relatively far apart. As the movement of water molecules slows down when liquid water changes to ice, hydrogen bonds form that space the molecules relatively far apart. As the movement of water molecules slows down when liquid water changes to ice, hydrogen bonds break allowing the molecules to move closer together. As the movement of water molecules slows down when liquid water changes to ice, hydrogen bonds form that bring the molecules close together.

Answer 43

As the movement of water molecules slows down when liquid water changes to ice, hydrogen bonds form that space the molecules relatively far apart.

Question 44

When 1 g of sugar is dissolved in 500 mL of water, the sugar is called the ___ and water is called the ___

Answer 44

solute , solvent

Question 46

Which of the following best describes the entire alkaline range of the pH scale? Multiple choice question. pH values between 6 and 14. pH values between 8 and 14 pH values between 7 and 13 Any pH value above 7

Answer 46

Any pH value above 7

Question 47

Which of the following statements about the pH inside of cells are true? Multiple select question. Even small changes in pH can alter the shape of enzymes and other proteins. Altering the shape of enzymes or other proteins generally has no effect on their function. It is important for cells to maintain a fairly constant pH. Most enzymes in living systems are extremely sensitive to pH.

Answer 47

Even small changes in pH can alter the shape of enzymes and other proteins. It is important for cells to maintain a fairly constant pH.Most enzymes in living systems are extremely sensitive to pH.

Question 48

Which of the following molecules are nonpolar? Multiple select question. H2O CH4 N2 O2

Answer 48

CH4, N2,O2 equally shared

Question 49

____ is made of two or more atoms held together by chemical bonds in a stable association. The atoms may or may not belong to the same element.

Question 49

Match each type of bond or interaction with its description. covalent bond covalent bond Drop zone Sharing of electrons correct Toggle Button Unavailable. Sharing of electrons ionic bond ionic bond Drop zone Attraction between oppositely charged atoms correct Toggle Button Unavailable. Attraction between oppositely charged atoms hydrogen bond hydrogen bond Drop zone Attraction between a covalently bound H atom with a slight positive charge and another covalently bound atom with a slight negative charge correct Toggle Button Unavailable. Attraction between a covalently bound H atom with a slight positive charge and another covalently bound atom with a slight negative charge hydrophobic interaction hydrophobic interaction Drop zone Nonpolar regions of a molecule are forced together in order to minimize contact with water molecules correct Toggle Button Unavailable. Nonpolar regions of a molecule are forced together in order to minimize contact with water molecules van der Waals attraction van der Waals attraction Drop zone Weak attraction between atoms due to oppositely polarized electron clouds correct Toggle Button Unavailable. Weak attraction between atoms due to oppositely polarized electron clouds

Answer 49

ye

Question 50

Which bond is formed by an unequal sharing of one or more electron pairs? Multiple choice question. Ionic Nonpolar covalent Polar covalent

Answer 50

polar covalent

Question 51

In living systems, ionic compounds generally exist as Blank______. Multiple choice question. ionic crystals individual ions nonpolar atoms polar atoms

Answer 51

individual ions

Question 52

What is true of a molecule of gaseous hydrogen (H2)? Multiple choice question. It has one partial positive charge and one partial negative charge which are balanced. It has a partial positive charge. It has no net charge.

Answer 52

no net charge

Question 53

Because of the many hydrogen bonds that form between its molecules, water has a very high ____ This allows small insects to "walk on water."

Answer 53

surface tension

Question 54

The ___ of a substance is a measure of how rapidly its individual molecules are moving.

Answer 54

temperature

Question 55

The amount of energy required to change 1 g of a substance from a liquid to a gas is called which of the following? Multiple choice question. Condensation constant Vaporization energy Heat of vaporization Enthalpy

Answer 55

Heat of Vaporization

Question 56

When a sugar crystal is placed in water, every time a sucrose molecule dissociates from the crystal, water molecules surround it in a cloud forming a(n) ____ shell that prevents it from associating with other sucrose molecules.

Answer 56

hydration

Question 57

Hydrophobic substances tend to do which of the following? Multiple select question. Repel water Readily form hydrogen bonds with water Aggregate together when mixed with water in order to minimize contact with water Assume shapes that minimize contact with water

Answer 57

Repel water Aggregate together when mixed with water in order to minimize contact with water Assume shapes that minimize contact with water

Question 58

How does the partial charge of a polar covalent bond compare to the unit charge of an ion? Multiple choice question. A partial charges is about the same as a unit of charge. A partial charges is far smaller than a unit of charge. A partial charge is about twice larger than a unit of charge. A partial charges is far smaller than a unit of charge.

Answer 58

A partial charges is far smaller than a unit of charge.

Question 59

What is the charge of a hydroxide ion? Multiple choice question. -1 +2 -2 +1

Answer 59

-1

Question 60

When an acid is dissolved in water, how does it change the solution's pH? Multiple choice question. It decreases the solution's pH by removing protons from the solution. It increases the solution's pH by releasing protons in the solution. It increases the solution's pH by removing protons from the solution. It decreases the solution's pH by releasing protons in the solution.

Answer 60

It decreases the solution's pH by releasing protons in the solution.

Question 61

When an ion or a polar molecule, such as sucrose, dissolves in water, they are surrounded by multiple layers of water molecules, collectively called which of the following? Hydration shell Water cloud Hydroxyl shell Hydrogen bonding layers

Answer 61

Hydration shell

Question 62

The ____ charges produced by a polar covalent bond are much smaller than the unit charge of an ion.

Answer 62

partial

Question 63

A hydrogen ion, formed during the dissociation of water, has a charge of which of the following? Multiple choice question. -2 +1 -1

Answer 63

+1

Question 64

The key buffer in human blood is an acid-base pair consisting of ___ acid and ______ (a base).

Answer 64

carbonic,bicarbonate