Water's Role in Living Organisms

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Questions and Answers

Which of the following is NOT a key characteristic of a solvent?

It forms a homogeneous mixture with the solute.
It can be a liquid.
It is the substance that is dissolved in a solution. (correct)
It is the dissolving agent of a solution.

What makes water a good solvent?

Its ability to form hydrogen bonds. (correct)
Its lack of polarity.
Its ability to dissolve non-polar molecules.
Its high density.

How does the ability of water to moderate temperature affect organisms?

Water's ability to moderate temperature allows organisms to survive in extreme environments.
Water's ability to moderate temperature helps to keep organisms' internal temperatures stable. (correct)
The ability of water to moderate temperature helps organisms cool down through evaporative cooling.
Water's ability to moderate temperature allows organisms to regulate their body temperature.

When a polar compound dissolves in water, what structure forms around the charged regions of the molecule or ion?

A hydration shell. (C) Signup and view all the answers

What happens to water molecules as they transition from liquid to solid (ice)?

The water molecules arrange themselves in a less dense crystal structure, causing ice to float. (A), The hydrogen bonds between water molecules become more stable and less likely to break. (C) Signup and view all the answers

Why is it important that ice floats in liquid water?

It prevents bodies of water from freezing solid, allowing aquatic life to survive. (B) Signup and view all the answers

Which of the following is an example of a polar molecule that can dissolve in water?

Sodium chloride (NaCl) (C) Signup and view all the answers

What is the term used for a solution where water is the solvent?

Aqueous solution. (D) Signup and view all the answers

Which of the following statements is TRUE regarding the density of water?

The density of water reaches its maximum at 4°C (39°F) and decreases as the temperature goes up or down. (B) Signup and view all the answers

What is the primary factor that drives the fall and spring turnover in lakes?

The changing temperature of the water, which affects its density. (D) Signup and view all the answers

Which of the following statements accurately describes the ability of large molecules to dissolve in water?

Large molecules can dissolve in water only if they have polar regions. (D) Signup and view all the answers

What type of interaction is primarily responsible for the dissolution of polar molecules in water?

Hydrogen bonds. (C) Signup and view all the answers

Which of the following is an example of a substance that is NOT typically soluble in water?

Oil. (B) Signup and view all the answers

What is the relationship between the amount of solute and the rate of reaction?

More solute increases the number of collisions. (C) Signup and view all the answers

What does adding an acid do to a solution?

Increases the concentration of H+ ions. (A) Signup and view all the answers

Which statement correctly describes a base?

A base increases the concentration of OH- in a solution. (A) Signup and view all the answers

What is the significance of a buffer system in biological solutions?

Buffers minimize changes in concentrations of H+ and OH-. (C) Signup and view all the answers

What is true about the dynamic equilibrium of water?

Water constantly oscillates between hydronium and hydroxide ions. (A) Signup and view all the answers

What is the formula for determining pH?

pH = -log [H+] (B) Signup and view all the answers

In what conditions does bicarbonate act in the human buffer system?

In both acidic and basic conditions to moderate pH changes. (C) Signup and view all the answers

What occurs in a solution when it becomes acidic?

Carbonic acid is produced from bicarbonate. (D) Signup and view all the answers

Which of the following is NOT a property of water that supports life?

Its ability to sustain magnetism (A) Signup and view all the answers

What is the primary reason for water's high specific heat?

The strong cohesive forces due to hydrogen bonding (A) Signup and view all the answers

What is the difference between heat and temperature?

Heat is the measure of the total kinetic energy, while temperature is the measure of its intensity (C) Signup and view all the answers

What is the fundamental property of water that allows it to effectively moderate temperature?

Water's high specific heat (C) Signup and view all the answers

What is the consequence of water having a high specific heat?

Water readily absorbs and releases heat. (C) Signup and view all the answers

What is the difference between cohesion and adhesion?

Cohesion is attraction between the same substances while adhesion is attraction between different substances (A) Signup and view all the answers

What is surface tension?

The force that resists an object from penetrating the surface of water (C) Signup and view all the answers

What is the primary reason for water's ability to act as a solvent?

Water's ability to form hydrogen bonds (D) Signup and view all the answers

What is the role of hydrogen bonds in the cohesive ability of water?

Hydrogen bonds create strong attractions between water molecules (A) Signup and view all the answers

Which of the following is a direct consequence of water's cohesive ability?

Water's surface tension (A) Signup and view all the answers

Flashcards

Moderate Temperature

Water's ability to absorb heat and stabilize temperature in organisms and environments.

Evaporative Cooling

Process where heat is absorbed from the skin as water vaporizes, cooling the surface.