Bio181 Chapter 3

What is cohesion?

the attraction of water molecules to other water molecules

Surface Tension

A measure of the force necessary to stretch or break the surface of a liquid

Temperature

Measure of heat intensity due to the AVERAGE kinetic energy of a substance.

Heat

Measure of the TOTAL kinetic energy of a substance due to molecular motion.

What is a calorie?

The energy required to raise the temperature of 1 gram of water by 1°C

Solution

Solvent and Solute added together

Solvent

the dissolving agent (water)

Solute

what gets dissolved

Hydrophobic

Hates water (will NOT dissolve in water)

Hydrophilic

Loves water (will dissolve in water)

What is molarity?

The number of moles of solute per liter of solution

What is Avogadro's number?

The number of molecules in a mole (6.02 × 10²³)

The partial negative charge in a molecule of water occurs because?

the shared electrons spend more time around the oxygen than around the hydrogen

Why does water have a high specific heat?

Energy is used to break hydrogen bonds rather than raise temperature

What is adhesion?

Water's attraction to other (non-water) substances

Why does ice float on liquid water?

Solid water's density is less than liquid water's density

What is a mole?

The amount of a substance with a mass in grams numerically equivalent to its weight in daltons

What is pH?

Power of Hydrogen

What does pH 7 mean?

[H⁺] = [OH⁻] (neutral)

What are acids?

Substances that increase the relative hydrogen ion (H⁺) concentration of a solution

What are bases?

Substances that decrease the relative H⁺ concentration (increase OH⁻)

What happens to pH when a strong acid is added to water?

pH decreases (lowers)

What are buffers?

Substances that minimize large, sudden changes in pH