Unit 1 – Chemistry of Life (Vocabulary Flashcards)

Vocabulary flashcards covering fundamental terms from Unit 1: Chemistry of Life, including bonds, water properties, acids/bases, pH, buffers, and related concepts.

Covalent bond

Bond formed by sharing electrons between atoms.

Polar covalent bond

A covalent bond with unequal sharing of electrons, creating partial charges.

Nonpolar covalent bond

A covalent bond with equal sharing of electrons, little to no partial charges.

Ionic bond

Bond formed by electrostatic attraction between oppositely charged ions after electron transfer.

Electronegativity

Tendency of an atom to attract electrons in a chemical bond.

Hydrogen bond

Weak attraction between a partially positive hydrogen and a partially negative atom (usually O, N, or F).

Hydrophilic

Molecules with partial or full charges that interact with water.

Hydrophobic

Molecules that lack charges and interact poorly with water.

Water as solvent

Water is the solvent of life; its polarity allows many substances to dissolve.

Adhesion

Water’s attraction to surfaces other than itself.

Cohesion

Water molecules sticking to each other via hydrogen bonds.

Temperature moderation

Water’s ability to moderate temperature due to hydrogen bonding.

Expansion upon freezing

Ice is less dense than liquid water and floats because of hydrogen bonding.

pH

Measure of hydrogen ion concentration in solution; pH = -log[H+].

Acid

Substance that increases [H+] in solution; pH < 7.

Base

Substance that decreases [H+] or increases [OH-]; pH > 7.

pH scale

Scale from 0 to 14 representing acidity/basicity; 7 is neutral.

Buffer

Substance that resists changes in pH by accepting or donating H+.

Carbonic acid/bicarbonate buffer

Blood buffer system H2CO3 ⇌ HCO3- + H+ that helps maintain blood pH.

pH and pOH relationship

In aqueous solutions, pH + pOH = 14.

Hydration shell

Layer of water molecules surrounding dissolved ions.

Valence electrons

Electrons in the outermost shell used for bonding.

Octet rule

Atoms tend to have eight electrons in their outermost shell for stability.

Electron shell

Discrete energy levels around a nucleus that hold electrons.

Electronegativity trend

H ≈ C < N < O < F; higher electronegativity attracts electrons more.

Cation

Ion with a positive charge; atom that has lost electrons.

Anion

Ion with a negative charge; atom that has gained electrons.