MasteringBiology Chapter 3 Quiz and Flashcards

Questions and Answers

Each water molecule is joined to _ other water molecules by bonds.

four...hydrogen

The unequal sharing of electrons within a water molecule makes the water molecule _____.

polar Signup and view all the answers

The tendency of an atom to pull electrons toward itself is referred to as its _____.

electronegativity Signup and view all the answers

In this molecule, what type of bond is found between the oxygen and hydrogens?

polar covalent Signup and view all the answers

Which of these bonds is weakest?

Signup and view all the answers

Why isn't this insect drowning?

Surface tension Signup and view all the answers

Which statement must be mentioned in explaining why amphipathic molecules line up at a water surface?

Polar groups attract one another Signup and view all the answers

Dissolving is best described as...

a mingling of molecules and/or ions Signup and view all the answers

Water is a source of ______________ for chemical reactions in cells.

Both (A) and (B) Signup and view all the answers

Which statement is true of water's tensile strength?

(A), (B), and (C) Signup and view all the answers

Water has surface tension because...

hydrogen bonds between surface water molecules resist being stretched Signup and view all the answers

Which of the following helps most to explain why water has a high specific heat?

(a) A water molecule can make 4 hydrogen bonds Signup and view all the answers

Which factor is important in making it possible to cool yourself by sweating?

Both (A) and (B) Signup and view all the answers

Though you add heat, the temperature of boiling water remains constant because...

it takes energy to break hydrogen bonds Signup and view all the answers

Which statement helps to explain why ice is less dense than liquid water?

Both (A) and (B) Signup and view all the answers

The open spaces in water's crystal structure make it possible for...

(a) aquatic life to exist at the North Pole Signup and view all the answers

Why doesn't oil mix with water?

(c) Polar molecules attract one another Signup and view all the answers

Many of water's emergent properties, such as its cohesion, its high specific heat, and its high heat of vaporization, result from the fact that water molecules _____

are attracted to each other by partial negative and positive charges on the oxygen and hydrogen atoms, respectively Signup and view all the answers

Because organisms are made primarily of water, they resist rapid temperature changes. This useful quality is based on water's _____.

high specific heat Signup and view all the answers

In a neutral solution the concentration of _____

hydrogen ions is equal to the concentration of hydroxide ions Signup and view all the answers

How does the pH of the solution on the right compare with that of the solution on the left?

The solution on the right is basic relative to the solution on the left Signup and view all the answers

A pH of 6 is how many times more acidic than a pH of 9?

1,000 Signup and view all the answers

Select the statement that best describes a buffer.

A buffer resists change in pH by accepting hydrogen ions when acids are added to the solution and donating hydrogen ions when bases are added Signup and view all the answers

Which statement is true of pH buffers?

(c) They consist of weak acids and weak bases Signup and view all the answers

A buffer consists of undissociated acid (HA) and the ion made by dissociating the acid (A-). How does this system buffer a solution against decreases in pH?

(b) A- reacts with H+ to become HA Signup and view all the answers

Buffers work best when...

about half of the buffer molecules are dissociated Signup and view all the answers

How does the way a buffer stabilizes pH during addition of acid differ from the way the same buffer stabilizes pH during addition of base?

It's the same reaction running backward or forward Signup and view all the answers

Which answer helps to explain why all living cells need pH buffers?

Amino acid side chains have many carboxyl and amino groups Signup and view all the answers

To make a buffer, you need to...

(d) have a weak acid or a weak base half ionized in water Signup and view all the answers

Which property of water allows dogs to cool themselves by panting?

water's high heat of vaporization Signup and view all the answers

What is the difference between H+ concentration in an acidic solution such as lemon juice (pH 2) and a basic solution such as household bleach (pH 13)?

The H+ concentration of lemon juice is higher than the H+ concentration of household bleach by a factor of 10^11 (100 billion) Signup and view all the answers

Study Notes

Water Molecule and Properties

Water molecules form four hydrogen bonds with other water molecules, contributing to its unique properties.
The polarity of water results from unequal sharing of electrons, leading to partial positive and negative charges.
Electronegativity refers to an atom's ability to attract electrons towards itself, influencing chemical bonding.
Bonds in water include polar covalent bonds between oxygen and hydrogen atoms.

Physical Properties of Water

Surface tension allows insects to walk on water due to the cohesive properties arising from hydrogen bonds.
Amphipathic molecules line up at water surfaces because polar groups attract each other.
Dissolving involves a mixing process of molecules or ions, highlighting water's solvent capabilities.
Water acts as a source of hydrogen and oxygen atoms for chemical reactions in cells.

Specific Heat and Temperature Regulation

Water's high specific heat stems from the ability to form four hydrogen bonds, making it resistant to temperature changes.
Sweating cools the body as it utilizes the relatively weak hydrogen bonds that break during evaporation.
The temperature of boiling water remains constant despite heat addition because energy is required to break hydrogen bonds.

Density and Ice Formation

Ice is less dense than liquid water due to the specific angles of hydrogen bonds that create open space in its crystal structure.
This property allows aquatic life to thrive underneath ice-covered surfaces.

Interaction with Other Substances

Water does not mix with oil because polar and non-polar molecules have different interactions, with polar molecules preferring to associate with each other.
Many of water's emergent properties, such as cohesion and high heat of vaporization, result from the attraction between charged molecules.

pH and Buffers

In neutral solutions, hydrogen ion concentration equals hydroxide ion concentration.
A pH of 6 is 1,000 times more acidic than a pH of 9, indicating significant differences in acidity.
Buffers resist changes in pH by interacting with hydrogen ions; they consist of weak acids and bases.
The buffering system enhances stability in solutions by reacting to additions of acids and bases, ensuring organisms maintain appropriate pH levels.
Amino acid side chains in cells possess carboxyl and amino groups that necessitate the presence of pH buffers.

Practical Applications of pH Buffers

Effective buffers are made from weak acids or bases that are partially ionized in water, stabilizing pH during chemical reactions.
The functionality of a buffer depends on having a balanced ratio of dissociated and undissociated molecules for optimal performance.

Unique Properties of Water

Dogs can cool down by panting due to water's high heat of vaporization, which facilitates evaporative cooling.
The H+ concentration in acidic solutions like lemon juice (pH 2) is exponentially higher than in basic solutions like bleach (pH 13) by a factor of 10^11.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge of key concepts from Chapter 3 of MasteringBiology. This quiz covers essential topics such as water molecules, polarity, and electronegativity. Perfect for students looking to reinforce their understanding of biology fundamentals.

MasteringBiology Chapter 3 Flashcards

Questions and Answers

Each water molecule is joined to _____ other water molecules by ____ bonds.

Each water molecule is joined to _____ other water molecules by ____ bonds.

Each water molecule is joined to _____ other water molecules by ____ bonds.

The unequal sharing of electrons within a water molecule makes the water molecule _____.

The tendency of an atom to pull electrons toward itself is referred to as its _____.

In this molecule, what type of bond is found between the oxygen and hydrogens?

Which of these bonds is weakest?

Why isn't this insect drowning?

Which statement must be mentioned in explaining why amphipathic molecules line up at a water surface?

Dissolving is best described as...

Water is a source of ______________ for chemical reactions in cells.

Which statement is true of water's tensile strength?

Water has surface tension because...

Which of the following helps most to explain why water has a high specific heat?

Which factor is important in making it possible to cool yourself by sweating?

Though you add heat, the temperature of boiling water remains constant because...

Which statement helps to explain why ice is less dense than liquid water?

The open spaces in water's crystal structure make it possible for...

Why doesn't oil mix with water?

Many of water's emergent properties, such as its cohesion, its high specific heat, and its high heat of vaporization, result from the fact that water molecules _____

Because organisms are made primarily of water, they resist rapid temperature changes. This useful quality is based on water's _____.

In a neutral solution the concentration of _____

How does the pH of the solution on the right compare with that of the solution on the left?

A pH of 6 is how many times more acidic than a pH of 9?

Select the statement that best describes a buffer.

Which statement is true of pH buffers?

A buffer consists of undissociated acid (HA) and the ion made by dissociating the acid (A-). How does this system buffer a solution against decreases in pH?

Buffers work best when...

How does the way a buffer stabilizes pH during addition of acid differ from the way the same buffer stabilizes pH during addition of base?

Which answer helps to explain why all living cells need pH buffers?

To make a buffer, you need to...

Which property of water allows dogs to cool themselves by panting?

What is the difference between H+ concentration in an acidic solution such as lemon juice (pH 2) and a basic solution such as household bleach (pH 13)?

Study Notes

Water Molecule and Properties

Physical Properties of Water

Specific Heat and Temperature Regulation

Density and Ice Formation

Interaction with Other Substances

pH and Buffers

Practical Applications of pH Buffers

Unique Properties of Water

Studying That Suits You

Description

More Quizzes Like This

Polarity of Water Molecules and Ice Floating Quiz

The Water Molecule

Properties of Water Molecules: Polarity and Interactions

Polarity of Water Molecules

Each water molecule is joined to _ other water molecules by bonds.

Each water molecule is joined to _ other water molecules by bonds.

Each water molecule is joined to _ other water molecules by bonds.