Bio Chap 3

What is the reason for water's polarity?

The unequal sharing of electrons in its polar covalent bonds, with oxygen being more electronegative than hydrogen.

What charge does the oxygen atom in a water molecule have?

A partial negative charge (δ−).

What property of water results from hydrogen bonding between water molecules?

Cohesion, which is the tendency of water molecules to stick together.

How does water's cohesion contribute to surface tension?

Cohesion creates surface tension, allowing some insects to walk on water.

What is adhesion in the context of water?

The clinging of water to other substances.

How does cohesion and adhesion work together in plants?

Cohesion pulls water column up while adhesion helps water stick to cell walls, preventing it from falling.

What is water's specific heat?

The amount of heat needed to raise the temperature of 1 gram of a substance by 1 degree Celsius.

What gives water its high specific heat?

Hydrogen bonding, which requires a lot of heat energy to break.

What is evaporative cooling?

A process where the molecules with the highest kinetic energy evaporate, cooling the remaining liquid.

Why is ice less dense than liquid water?

Due to hydrogen bonding, ice forms a crystalline lattice that spaces molecules farther apart.

What is the significance of ice floating on water?

It prevents bodies of water from freezing solid, allowing life to exist beneath the surface.

What does it mean for water to be a universal solvent?

Water can dissolve a wide variety of substances due to its polarity.

What happens when an acid is added to a solution?

It increases the hydrogen ion concentration of the solution.

What is a base in terms of pH?

A substance that decreases the hydrogen ion concentration of a solution.

What does the pH scale represent?

The acidity or basicity of a solution, measured as the negative logarithm of hydrogen ion concentration.

What is considered a neutral pH?

A pH of 7, with equal concentrations of H+ and OH−.

What is the role of buffers in biological systems?

They help maintain a stable pH by accepting or donating hydrogen ions.

What is ocean acidification?

The lowering of seawater pH due to the absorption of carbon dioxide from the atmosphere.

What is a significant consequence of ocean acidification for marine life?

It reduces the availability of carbonate ions, crucial for organisms that build shells and skeletons.

What is the role of carbonic acid in ocean acidification?

It forms from the reaction of dissolved CO2 with water, lowering seawater pH.

What type of ion is formed when a hydrogen atom shifts in a water molecule?

A hydronium ion (H3O+) and a hydroxide ion (OH−).

What relationship does the pH scale have with hydrogen ion concentration?

Each pH unit represents a tenfold difference in H+ concentration.

What happens to the temperature of ocean water due to water’s high specific heat?

It stabilizes ocean temperatures, creating favorable environments for life.

What is the impact of human activities on ocean pH?

They contribute to ocean acidification, affecting marine ecosystems.

What are hydrophilic substances?

Substances that readily dissolve in water, meaning they are water-loving.

What are hydrophobic substances?

Substances that do not dissolve in water, meaning they are water-fearing.

How does evaporative cooling help terrestrial organisms?

It prevents overheating, as in the case of sweating in humans.

What occurs in the carbonic acid-bicarbonate buffering system?

It helps maintain the pH of blood by acting as a buffer.

Why is it important to understand the properties of water?

Because they play a crucial role in maintaining life on Earth.

What aspect of water allows some insects to walk on its surface?

The surface tension created by cohesion between water molecules.

What happens to water when ice forms?

Hydrogen bonds lock the molecules into a crystalline structure, making ice less dense.

What is the main cause of ocean acidification today?

The burning of fossil fuels releasing carbon dioxide into the atmosphere.

How do buffers typically work in solutions?

By accepting or donating hydrogen ions to maintain pH balance.

What role does sunlight play in the process of evaporation?

It provides energy to enable the high heat of vaporization, causing molecules to evaporate.

What makes water an excellent solvent for ionic compounds?

Water’s polarity allows it to surround and separate ions, forming hydration shells.

What happens to the pH of a solution with a higher concentration of H+ ions?

The pH decreases, making the solution more acidic.

What ecological significance does maintaining the pH of oceans have?

It is vital for the health of marine ecosystems, particularly for coral reefs.