Biology 101: Chapter 3: Water & Life

Cohesion refers to the intermolecular attraction between water molecules due to hydrogen bonding, which allows water to form cohesive drops and surface tension.

Adhesion refers to the ability of water molecules to stick to other surfaces through intermolecular forces, such as hydrogen bonding. This is what allows for phenomena such as surface tension and capillary action.

Heat is defined as the thermal energy in transfer from one body of matter to another. It is not a type of light energy, sound produced by fire, or the size of an object.

Temperature is a measure of the average kinetic energy of the molecules in a body of matter. It is not related to the amount of heat, density, or color of the matter.

Thermal energy is the internal energy in a system due to its temperature, while the incorrect answers are related to other forms of energy.

Heat of Vaporization refers to the amount of heat energy required for a liquid to change into a gas at its boiling point, not related to the temperature or energy needed for freezing or the process of gas turning into a liquid.

Evaporative cooling refers to the cooling effect produced when a liquid evaporates and the remaining surface cools. It is different from the other options provided.

A solution specifically involves a solvent (the substance in which the solute is dissolved) and a solute (the substance that is dissolved in the solvent). The other incorrect answers do not fully capture the definition of a solution.

A solvent is the substance in which another substance is dissolved, forming a solution. It is typically the most abundant part of the solution.

A solute is the component that is dissolved in the solvent, making up the lesser part of a solution.

The term 'hydrophilic' refers to polar compounds that have an affinity for water and readily dissolve in it, such as salts and alcohol. This is due to their ability to form hydrogen bonds with water molecules.

Hydrophobic compounds are non-polar and repel water molecules, causing them to minimally dissolve in water. This is in contrast to polar compounds that dissolve easily in water. Examples of hydrophobic compounds include oils and fats.

A hydrogen ion (H+) is formed when the hydrogen atom loses its electron, leaving behind a proton. This results in a positively charged ion.

When a water molecule loses a proton (H+), it forms the Hydroxide Ion (OH-), which has a negative charge due to gaining an extra electron.

An acid is specifically defined as a compound that donates protons (H+) to a solution, leading to a lower pH. Acids typically have a sour taste and can react with bases to form salts.

A base is a substance that can take up hydrogen ions or release hydroxide ions, resulting in a pH greater than 7. It is characterized by its bitter taste.

pH is specifically a measure of hydrogen ion concentration in a solution, which is represented on a logarithmic scale from 0 to 14. It is not related to oxygen, sodium, or chloride ions in this context.

A buffer is a solution that helps maintain a stable pH level by resisting changes in acidity or alkalinity. It is commonly used in various scientific experiments and industrial processes to control pH levels.

This question aims to test the understanding of the life-sustaining properties of water and how its structure, specifically the polarity, contributes to each property. The correct answer, Cohesive Behavior, is directly related to water's polarity, which allows water molecules to form hydrogen bonds and stick together. Adhesive Behavior, High Specific Heat, and Expansion Upon Freezing are also important properties of water, each influenced by its unique structure and polarity.

The correct answer is Capillary Action, where cohesion and adhesion allow water to move up the tree. Root pressure, photosynthesis, and transpiration do not directly contribute to the upward movement of water in a tree like capillary action does.

The ability of a water strider to walk on water is primarily due to the surface tension of water, which allows the water molecules to cling together tightly near the surface. This enables the water strider to distribute its weight effectively and take advantage of the surface tension to stay afloat.

Water's high specific heat is key in minimizing temperature fluctuations along the coast by absorbing and releasing heat effectively.

Ice floats in water due to its lower density in the solid state compared to the liquid state, allowing it to stay on the surface rather than sinking.

Salt dissolves in water due to the attraction between the polar water molecules and the ionic salt molecules, allowing them to separate and disperse throughout the water.

The correct answer explains that acids release H+ ions and have a pH less than 7, while bases release OH- ions and have a pH greater than 7. Options A, B, and C provide incorrect statements that do not align with the definitions of acids and bases.

pH is specifically related to the concentration of hydrogen ions (H+) in a solution, not hydroxide ions (OH-), temperature, or color intensity.

Buffers work by resisting changes in pH through the addition or absorption of either H+ or OH- ions as needed to maintain a stable pH level.