CH 3 -Water and Life

These flashcards cover key vocabulary and concepts regarding the properties of water and its importance to life as discussed in the lecture notes.

Water (H2O)

A polar molecule that is essential for all known forms of life.

Polar molecule

A molecule with a distribution of charge that leads to partially positive and negative ends.

Hydrogen bonds

Weak attractions that form between oppositely charged regions of water molecules.

Cohesion

The tendency of water molecules to stick together, resulting from hydrogen bonding.

Adhesion

The attraction between water molecules and different substances, which helps counter gravity.

Specific heat

The amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1ºC.

Heat of vaporization

The heat required to convert 1 g of liquid into gas.

Evaporative cooling

A process in which the surface of a liquid cools as molecules with the highest kinetic energy escape.

Hydrophilic substances

Substances that have an affinity for water, often ions or polar molecules.

Hydrophobic substances

Substances that do not have an affinity for water, typically nonpolar molecules.

Acid

A substance that increases the H+ concentration of a solution.

Base

A substance that reduces the H+ concentration of a solution.

pH scale

A scale used to specify the acidity or basicity of an aqueous solution, with 7 being neutral.

Buffers

Substances that minimize changes in concentrations of H+ and OH– in a solution.

Ocean acidification

The decrease in pH of the Earth's oceans caused by the uptake of CO2 from the atmosphere.

Water (H2O)

A polar molecule that is essential for all known forms of life.

Polar molecule

A molecule with a distribution of charge that leads to partially positive and negative ends.

Hydrogen bonds

Weak attractions that form between oppositely charged regions of water molecules.

Cohesion

The tendency of water molecules to stick together, resulting from hydrogen bonding.

Adhesion

The attraction between water molecules and different substances, which helps counter gravity.

Specific heat

The amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1ºC.

Heat of vaporization

The heat required to convert 1 g of liquid into gas.

Evaporative cooling

A process in which the surface of a liquid cools as molecules with the highest kinetic energy escape.

Hydrophilic substances

Substances that have an affinity for water, often ions or polar molecules.

Hydrophobic substances

Substances that do not have an affinity for water, typically nonpolar molecules.

Acid

A substance that increases the H+ concentration of a solution.

Base

A substance that reduces the H+ concentration of a solution.

pH scale

A scale used to specify the acidity or basicity of an aqueous solution, with 7 being neutral.

Buffers

Substances that minimize changes in concentrations of H+ and OH– in a solution.

Ocean acidification

The decrease in pH of the Earth's oceans caused by the uptake of CO2 from the atmosphere.

What is capillary action?

The upward movement of water in a narrow tube against gravity, caused by the combined forces of cohesion and adhesion.

Why is ice less dense than liquid water?

When water freezes, hydrogen bonds become more stable and form a crystalline lattice, spreading the molecules further apart than in liquid water.

What is surface tension in water?

A measure of how difficult it is to stretch or break the surface of a liquid, largely due to strong hydrogen bonding among water molecules at the interface with air.

Why is water considered a "universal solvent"?

Due to its polarity, water can form hydrogen bonds with and dissolve a wide range of ionic compounds and polar molecules.

What is the ecological importance of ice floating?

It insulates the water below, preventing entire bodies of water from freezing solid and allowing aquatic life to survive.

How does water moderate temperature?

Water's high specific heat allows it to absorb and release large amounts of heat with only slight changes in its own temperature, moderating global climates and internal temperatures of organisms.

Water (H2O)

A polar molecule that is essential for all known forms of life.

Polar molecule

A molecule with a distribution of charge that leads to partially positive and negative ends.

Hydrogen bonds

Weak attractions that form between oppositely charged regions of water molecules.

Cohesion

The tendency of water molecules to stick together, resulting from hydrogen bonding.

Adhesion

The attraction between water molecules and different substances, which helps counter gravity.

Specific heat

The amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1ºC.

Heat of vaporization

The heat required to convert 1 g of liquid into gas.

Evaporative cooling

A process in which the surface of a liquid cools as molecules with the highest kinetic energy escape.

Hydrophilic substances

Substances that have an affinity for water, often ions or polar molecules.

Hydrophobic substances

Substances that do not have an affinity for water, typically nonpolar molecules.

Acid

A substance that increases the H+ concentration of a solution.

Base

A substance that reduces the H+ concentration of a solution.

pH scale

A scale used to specify the acidity or basicity of an aqueous solution, with 7 being neutral.

Buffers

Substances that minimize changes in concentrations of H+ and OH– in a solution.

Ocean acidification

The decrease in pH of the Earth's oceans caused by the uptake of CO2 from the atmosphere.

What is capillary action?

The upward movement of water in a narrow tube against gravity, caused by the combined forces of cohesion and adhesion.

Why is ice less dense than liquid water?

When water freezes, hydrogen bonds become more stable and form a crystalline lattice, spreading the molecules further apart than in liquid water.

What is surface tension in water?

A measure of how difficult it is to stretch or break the surface of a liquid, largely due to strong hydrogen bonding among water molecules at the interface with air.

Why is water considered a "universal solvent"?

Due to its polarity, water can form hydrogen bonds with and dissolve a wide range of ionic compounds and polar molecules.

What is the ecological importance of ice floating?

It insulates the water below, preventing entire bodies of water from freezing solid and allowing aquatic life to survive.

How does water moderate temperature?

Water's high specific heat allows it to absorb and release large amounts of heat with only slight changes in its own temperature, moderating global climates and internal temperatures of organisms.

What effect does water's surface tension have on small objects or organisms?

It allows them to float or move across the surface without sinking, due to the cohesive forces of water molecules.

What structural feature of water contributes to its high specific heat?

The extensive network of hydrogen bonds among water molecules, which require significant energy to break before temperature can increase.

What happens to heat energy when water's hydrogen bonds break or form?

Heat is absorbed when hydrogen bonds break (e.g., during melting/evaporation) and released when they form (e.g., during freezing/condensation).