chapter 3 vocab. principles of biology

Electronegativity

the tendency of an atom to attract a shared pair of electrons (or electron density) towards itself.

Polar Covalent Bond

A bond between 2 nonmetal atoms that have different electronegativities and therefore have unequal sharing of the bonding electron pair

Nonpolarcovalent bond

equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.

Hydrophilic

having a tendency to mix with, dissolve in, or be wetted by water.

Hydrophobic

tending to repel or fail to mix with water.

Amphipathic

Describing a molecule, such as a detergent, which has both hydrophobic and hydrophilic groups.

Specific heat capacity

the energy required to increase temperature of material of a certain mass by 1°C

Heat of vaporization

the amount of energy that must be added to a liquid substance, to transform a quantity of that substance into a gas.

Cohesion

the intermolecular attraction between like-molecules

Adhesion

the tendency of dissimilar particles or surfaces to cling to one another

Capillary Action

ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity.

Density

a measure of mass per volume.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid. Water has a high surface tension because of the hydrogen bonding of surface molecules.

Temperature

A measure in degrees of the aver-age kinetic energy (thermal energy) of the atoms and molecules in a body of matter.

Solvent

The dissolving agent of a solution. Water is the most versatile solvent known.

Solute

A substance that is dissolved in a solution.

pH

A measure of hydrogen ion concentration equal to -log[H+] and ranging in value from 0 to 14.

Buffer

A solution that contains a weak acid and its corresponding base. A buffer minimizes changes in pH when acids or bases are added to the solution