Chapter 1-6 Notes: Water's Properties, Cohesion/Adhesion, Surfactants, and Heat Interaction

Flashcards cover water’s polarity and hydrogen bonding, cohesion vs. adhesion, surface tension and surfactants, capillary action, cell membrane structure, heat capacity and specific heat, and climate implications of water heating.

What is the polarity of a water molecule and the partial charges on hydrogen and oxygen?

Water is polar; the hydrogen atoms carry partial positive charges, and the oxygen carries a partial negative charge.

How many hydrogen bonds can a single water molecule typically form, and why is this important?

Typically up to four hydrogen bonds per molecule, which drives water's cohesion and many of its unique properties.

Differentiate cohesion and adhesion in water.

Cohesion: water molecules sticking to each other. Adhesion: water molecules sticking to other surfaces (e.g., glass, plant surfaces).

What is surface tension and how does it relate to water?

Surface tension is the cohesive force at the water's surface that allows it to resist external forces; it can be reduced or broken by surfactants.

Define surfactants and explain what amphipathic means.

Surfactants are molecules with both hydrophilic and hydrophobic parts (amphipathic) that lower surface tension and help mix oil and water.

How do phospholipids arrange themselves in relation to water in cell membranes?

Phospholipids have hydrophilic (water-loving) heads facing water and hydrophobic tails facing inward, forming a bilayer.

What is capillary action and why does it occur?

Capillary action is water rising in narrow tubes due to adhesive attraction to the walls and cohesive attraction among water molecules.

What does specific heat capacity mean, and what is water’s value?

Specific heat capacity is the energy required to raise the temperature of a substance by 1°C per unit mass. For water, about 4.18 J/g°C (1 cal/g°C).

Why does the ocean’s high heat capacity matter for climate and weather?

It stores large amounts of heat, moderating temperatures and influencing weather patterns and storm intensity.

How does increasing temperature affect oxygen solubility in water?

Oxygen solubility decreases as temperature increases.

What is the role of water’s heat capacity in energy transfer between land and air?

Water absorbs solar energy and releases it slowly, helping to stabilize coastal climates and slow temperature changes.

What does it mean for a molecule to be amphiphilic, and why is this important?

Amphiphilic (amphipathic) molecules have both hydrophilic and hydrophobic regions, enabling emulsification and interactions between oil and water.

What is a phospholipid bilayer and how does it relate to water?

A double layer of phospholipids with hydrophilic heads facing water and hydrophobic tails inward, forming cell membranes.

How do surfactants affect real-world examples like cleaning and fog prevention?

Surfactants reduce surface tension, helping to disperse oil and water and preventing fogging on goggles or lenses.

What is meant by 'breaking the surface' in the context of water’s surface tension?

Breaking the surface refers to an object penetrating the water’s surface, overcoming surface tension if force is sufficient; otherwise surface tension keeps the surface intact.

How does hydrogen bonding contribute to water’s resistance to temperature change?

Hydrogen bonds allow water to absorb and store heat, then release it slowly, reducing rapid temperature changes.