Water: Potential and Properties

Question 1

Water Potential

Answer 1

Measure of the potential energy of water in a solution that determines the direction it will move

-Water moves from high to low water potential.

Question 2

Solute Potential

Answer 2

A part of water potential due to the presence of dissolved solutes.

-Water moves toward lower (more negative) solute potential.

Question 3

Pressure potential

Answer 3

Pressure exerted by or on water

-Positive pressure increases water potential (helps maintain turgidity in plant cells).

Question 4

Water movement

Answer 4

Water moves from areas of higher water potential (less solute, more pressure) to areas of lower water potential (more solute, less pressure).

Question 5

Origin of Water on Earth

Answer 5

Volcanic activity: Released water vapor from Earth’s interior, which condensed into liquid water.

Comet and asteroid impacts: Brought additional water to Earth from space.

Question 6

Planetary conditions for water to remain

Answer 6

-Surface temperatures must allow water to exist in liquid form

-Sufficient gravity must exist to prevent water from escaping

Question 6

Structure and Polarity of Water Molecules

Answer 6

Water (H₂O) consists of one oxygen atom and two hydrogen atoms.

Polarity: Oxygen is more electronegative, creating a partial negative charge (δ-) and partial positive charges (δ+) on hydrogen atoms, leading to a polar molecule.

Question 6

Cohesion of Water Molecules

Answer 6

Cohesion: Water molecules are attracted to each other due to hydrogen bonding.

This creates high surface tension, allowing water to form droplets and enabling small organisms to walk on water.

Question 6

Hydrophilic Molecules

Answer 6

Hydrophilic: “Water-loving” substances that interact well with water.(forms hydrogen bonds)

Typically polar or ionic, allowing them to dissolve in water (e.g., salts, sugars).

Question 6

Adhesion Between Water and Other Polar Substances

Answer 6

Adhesion: Water molecules are attracted to other polar substances.

This property allows water to “stick” to surfaces, helping it move up plant stems (capillary action).

Question 7

Hydrophobic Molecules

Answer 7

Hydrophobic: “Water-fearing” substances that do not mix well with water.

Typically nonpolar, avoiding interaction with water (e.g., oils, fats).

Question 8

Physical Properties of Water

Answer 8

High specific heat: Resists temperature changes, stabilizing climates.

Viscosity: Water resistance to an object moving through it

Buyoncy: Object is less dense than liquid water, allowing it to floa because buoyant forces are upwards than abvove

Thermal Conductivity: The ability of a substance to transfer heat. Water has a high thermal conductivity.