Chapter Two The Nature of Molecules and Properties of Water Flashcards
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.
Electron Orbital
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
____
neutrons, electrons
A cation has a net ____
while an anion has a net
___ charge.
+ , -
Isotopes differ in the number of
____
neutrons
Regardless of their shape and position, electron orbitals can never contain more than
____ electrons
2
Valence electrons and their interactions determine the
___ properties of an element
chemical
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.
Energy must be added
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.
Chemically reactive, form chemical compounds, form bonds with other atoms
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.
their outer shell is full.
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
number of electrons, neutrons are what changes.
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
protons
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
protons in the nucleus
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
noble gasses, inert
A substance that cannot be broken down into simpler substances by ordinary chemical means is called a(n)
element
Which subatomic particles determine the atomic mass of an atom?
Multiple choice question.
Neutrons only
Protons and electrons
Protons only
Protons and neutrons
protons and neutrons
Almost all the mass of an atom is located in the
nucleus
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.
Ions are formed when atoms lose or gain one or more electrons.
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.
genetic mutations, cell death
The chemical behavior of an atom is determined by the number and configuration of its
electrons
Atoms, in which the number of electrons does not equal the number of protons, are called
ions
Chemical reactions that involve a transfer of electrons from one atom to another are called
redox
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
trace elements
Arrange the following states of water in order from most dense to least dense (start with most dense at the top).
Gas
Liquid
Solid
Liquid
Solid
Gas
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
a sodium atom loses an electron, while a chlorine atom gains an electron
True, discrete molecules form when atoms are connected by Blank______.
Multiple choice question.
either covalent or ionic bonds
covalent bonds
hydrogen bonds
ionic bonds
Covalent Bonds
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.
Electrically neutral, and electrical charge is uniform
____ bond is formed by when one or more electron pairs are unequally shared between two atoms.
polar
The attraction of water to other polar substances is called
adhesion
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.
Water molecules adhere to the surface of the glass.
It takes a large amount of heat energy to break
____ bonds between water molecules; this explains why water has a very
___ heat of vaporization.
hydrogen, high
Water tends to repel or exclude
___ molecules.
nonpolar
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
The tendency of non-polar molecules to clump together in water
Unlike
____ bonds, which produce a crystal lattice,
covalent
____ bonds are formed between 2 individual atoms, giving rise to true, discrete molecules.
ionic, covalent
True, discrete molecules form when atoms are connected by
covalent bonds
Which of the following molecules are nonpolar?
Multiple select question.
N2
CH4
O2
H2
N2, CH4 (C-H bonds are nonpolar ), O2c
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.
They have the same number of protons and electrons.
They are electrically neutral.
The distribution of electrical charge is not uniform.
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-
H* , OH-
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
lower : higher
A(n)
___ covalent bond involves an equal sharing of one or more pairs of electrons.
nonpolar
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
Water’s high heat of vaporization
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
H2O
__ covalent bond is formed by when one or more electron pairs are unequally shared between two atoms.
polar
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.
As the movement of water molecules slows down when liquid water changes to ice, hydrogen bonds form that space the molecules relatively far apart.
When 1 g of sugar is dissolved in 500 mL of water, the sugar is called the
___ and water is called the
___
solute , solvent
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
Any pH value above 7
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.
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.
Which of the following molecules are nonpolar?
Multiple select question.
H2O
CH4
N2
O2
CH4, N2,O2 equally shared
____ 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.
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
ye
Which bond is formed by an unequal sharing of one or more electron pairs?
Multiple choice question.
Ionic
Nonpolar covalent
Polar covalent
polar covalent
In living systems, ionic compounds generally exist as Blank______.
Multiple choice question.
ionic crystals
individual ions
nonpolar atoms
polar atoms
individual ions
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.
no net charge
Because of the many hydrogen bonds that form between its molecules, water has a very high ____
This allows small insects to “walk on water.”
surface tension
The
___ of a substance is a measure of how rapidly its individual molecules are moving.
temperature
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
Heat of Vaporization
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.
hydration
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
Repel water
Aggregate together when mixed with water in order to minimize contact with water
Assume shapes that minimize contact with water
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.
A partial charges is far smaller than a unit of charge.
What is the charge of a hydroxide ion?
Multiple choice question.
-1
+2
-2
+1
-1
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.
It decreases the solution’s pH by releasing protons in the solution.
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
Hydration shell
The
____ charges produced by a polar covalent bond are much smaller than the unit charge of an ion.
partial
A hydrogen ion, formed during the dissociation of water, has a charge of which of the following?
Multiple choice question.
-2
+1
-1
+1
The key buffer in human blood is an acid-base pair consisting of
___
acid and
______ (a base).
carbonic,bicarbonate
