Biology Chapter 3: Section 3-1 Review: Water

When a glass is filled to the brim with water, the water appears to bulge from the sides of the glass due to...

d....cohesion.

Hydrogen Bond

A hydrogen bond is a weak chemical bond between the hydrogen atom in one molecule and a negatively charged region of another molecule.

Polar compound

A polar compound is a compound with one side having a negative charge and the other side having a positive charge.

What property of water allows it to stick to a dry surface, such as a wooden countertop?

Adhesion allows water to stick to a dry surface

Adhesion

Adhesion is the attraction force between unlike substances.

What kinds of substances besides water can be involved in hydrogen bonds?

Any molecule that has a region of negative charge or a hydrogen atom with a slight positive charge can be involved in hydrogen bonding

How does water help cells keep an even temperature despite temperature changes in the environment?

Because of its hydrogen bonds, water must gain or lose a relatively large amount of energy for its temperature to change. It, therefore, tends to resist temperature changes

Cohesion

Cohesion is the attraction of like molecules to each other.

Explain why water forms large, round drops as it falls from a faucet with a slow leak.

Cohesive forces cause the water molecules in each drop to move as close as possible to one another, making the drop round.

Water is often called the universal solvent because it dissolves most substances that are important to living things. What does this suggest about the nature of those substances?

It suggests that the substances are most often polar molecules or ionic compounds.

Why is water a good solvent?

Water's polar nature allows it to dissolve other polar substances as well as ionic compounds.

When sodium chloride is dissolved in water, the sodium ions...

a....are attracted to the oxygen atoms of water molecules.

In a water molecule,...

b....the oxygen atom has a slight negative charge and the hydrogen atoms have a slight positive charge.

Hydrogen bonds...

c....hold water molecules to one another.

When liquid water is heated, most of the energy that the water initially absorbs is used to...

d....break the hydrogen bonds between the water molecules.