Molecules, Water, and Solutions Vocabulary

Comprehensive vocabulary flashcards generated from lecture notes covering chemical bonds, water properties, mixtures, solutions, colloids, suspensions, and acid-base chemistry.

Electrolytes

Substances that ionize in water and form solutions capable of conducting electric current, playing key roles in muscle and nerve function, chemical reactivity, osmotic effects, and electrical excitability.

Molecule

A particle composed of two or more atoms united by a chemical bond.

Compound

A molecule composed of two or more different elements.

Molecular Formula

A formula that identifies the constituent elements of a molecule and how many atoms of each element are present.

Structural Formula

A formula that identifies the spatial location and arrangement of each atom within a molecule.

Isomers

Molecules that share identical molecular formulae but have different structural arrangements of their atoms.

Mixtures

Combinations consisting of substances that are physically blended together but not chemically combined, where each substance retains its own chemical properties.

Solvency

The ability of a substance to dissolve other chemicals.

Universal Solvent

A title given to water because it dissolves more substances than any other solvent.

Hydrophilic

Describes substances that are polarized or charged and dissolve readily in water.

Hydrophobic

Describes substances that are nonpolar or neutral and do not dissolve in water.

Hydration Sphere

An orientation of water molecules surrounding dissolved ions, where water's negative pole faces $Na^+$ and its positive poles face negative ions.

Adhesion

The tendency of one substance to cling to another, such as water adhering to biological membranes to reduce friction around organs.

Cohesion

The tendency of molecules of the same substance to cling to each other, caused in water by hydrogen bonding.

Surface Film

A film on the surface of water created by water molecules being held together by surface tension.

Chemical Reactivity

The ability of a substance to participate in chemical reactions, such as water ionizing into $H^+$ and $OH^-$ in hydrolysis and dehydration synthesis.

Thermal Stability

The ability of water to stabilize internal body temperature due to its high heat capacity and hydrogen bonds that resist temperature increases.

Heat Capacity

The amount of heat required to raise the temperature of $1\,\text{g}$ of a substance by $1^\circ\text{C}$.

Calorie (cal)

The base unit of heat, defined as the amount of heat needed to raise the temperature of $1\,\text{g}$ of water by $1^\circ\text{C}$.

Solution

A mixture containing solute particles under $1\,\text{nm}$ mixed with a solvent; it does not scatter light, passes through most membranes, and does not separate upon standing.

Solute

The particle component of a solution (gas, solid, or liquid) that is dissolved in a solvent.

Solvent

The most abundant substance in a solution that dissolves the solute, usually water in biological systems.

Colloids

Mixtures (often of protein and water) with particles ranging from $1\text{--}100\,\text{nm}$ that scatter light, are too large to pass through semipermeable membranes, stay permanently mixed, and can change between liquid and gel states.

Suspension

A mixture containing particles exceeding $100\,\text{nm}$ that are cloudy or opaque, cannot pass through selectively permeable membranes, and separate upon standing.

Emulsion

A specific type of suspension where one liquid is suspended within another liquid.

Acid

A proton donor that releases $H^+$ ions in solution.

Base

A proton acceptor that accepts $H^+$ ions or releases $OH^-$ ions in water.

pH Scale

A measurement scale derived from the molarity of $H^+$ ions, where $7.0$ is neutral ($H^+ = OH^-$), below $7.0$ is acidic ($H^+ > OH^-$), and above $7.0$ is basic ($OH^- > H^+$).

Buffers

Chemical solutions that resist changes in pH to help maintain a stable, slightly basic blood pH.