Structure of Water and Hydrogen Bonding Flashcards

Vocabulary flashcards covering the chemical structure, hydrogen bonding, unique properties, solvent characteristics, and buffer systems of water from Unit 1.

Polar Covalent Bond

A chemical bond formed between atoms with differing electronegativities, such as the bonds connecting oxygen to hydrogen within a water molecule.

Cohesion

The property of water molecules forming hydrogen bonds with one another, making water cohesive or sticky and creating surface tension.

Adhesion

The attraction and hydrogen bonding between water molecules and other polar substances, such as water adhering to glassware to form a meniscus.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid, resulting from cohesion among water molecules.

Capillary Action

The movement of water upward through thin tubes against gravity, driven by a combination of adhesion and cohesion.

Transpiration

The process by which water moves up through a plant from roots to leaves and evaporates into the atmosphere, relying on cohesion and adhesion.

High Specific Heat Capacity

The property of water to resist changes in temperature because significant heat energy is required to alter the average kinetic energy of its molecules.

High Heat of Vaporization

The property requiring a large amount of heat energy for water to transition from a liquid state to a gaseous state.

Evaporative Cooling

A temperature-reduction process where liquid water molecules with higher kinetic energy evaporate, leaving behind remaining molecules with lower average kinetic energy.

Density of Ice

The physical property wherein solid water is less dense than liquid water because hydrogen bonds hold molecules in a crystalline lattice structure.

Solute

The substance that is dissolved in a solvent to form a solution.

Solvent

The liquid substance capable of dissolving other chemical substances (solutes).

Solution

A liquid mixture composed of solutes dissolved within a solvent.

Molarity (M)

A unit used to express the concentration of a solution, representing the amount of solute present in a given volume.

Hydrophilic

Refers to polar or ionic compounds that readily dissolve in water by forming hydrogen bonds with water molecules.

Hydrophobic

Refers to nonpolar substances, such as oils and triglycerides, that do not form hydrogen bonds and fail to dissolve in water.

Hydration Shell

A sphere of water molecules surrounding dissolved ions, where oxygen atoms orient toward cations like $\text{Na}^+$ and hydrogen atoms orient toward anions like $\text{Cl}^-$.

pH Scale

A scale measuring the concentration of hydrogen ions ($\text{H}^+$) in a solution, where each integer change represents a tenfold difference in $\text{H}^+$ concentration.

Buffer

A substance that resists changes in pH by donating $\text{H}^+$ ions when conditions are too basic or accepting $\text{H}^+$ ions when conditions are too acidic.

Bicarbonate Buffer System

A physiological buffer system ($\text{CO}_2 + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3 \rightleftharpoons \text{H}^+ + \text{HCO}_3^-$) regulated by the lungs and kidneys to maintain blood pH near neutral.