Chapter 3 Study Guide and Lecture on Chemical Bonds and Reactions

Vocabulary flashcards generated from Chapter 3 Study Guide and Lecture notes covering water properties, chemical bonds, biological receptors, and chemical reactions.

Polar Molecule

A molecule with partial charges on different sides due to unequal electron sharing, such as water where oxygen's eight protons pull shared electrons more strongly than hydrogen's single proton.

Cohesion

The phenomenon where molecules of the same substance, such as water molecules, are attracted to and stick to each other.

Adhesion

The attraction and clinging of one substance to a different substance.

Specific Heat

The amount of heat required to change the temperature of a substance by a given amount.

Solvent of Life

A term describing water's ability to dissolve polar and charged molecules due to its polarity and partial charges.

Dissociation of Water

The chemical process where water molecules break apart into hydrogen ions ($H^+$) and hydroxide ions ($OH^-$).

Acid

A substance with a low pH that increases the concentration of $H^+$ ions in a solution.

Base

A substance with a high pH (alkaline) that has a higher concentration of $OH^-$ ions than $H^+$ ions.

Buffer

A chemical system that prevents drastic changes in pH when exposed to an acid or a base.

Covalent Bond

A strong chemical bond formed when two atoms share a pair of valence electrons.

Ionic Bond

A chemical bond formed when one atom donates an electron and another atom takes it, creating opposing full charges that attract each other.

Salt

An ionic compound created by any attraction between a positive and a negative charge.

Hydrogen Bond

A weak interaction between two polar molecules caused by an attraction between partial positive and partial negative charges.

Single Bond

A covalent bond where two atoms share one pair of valence electrons, represented in diagrams by a single dash or colon.

Double Bond

A covalent bond where two atoms share two pairs of valence electrons.

Triple Bond

A covalent bond where two atoms share three pairs of valence electrons, such as in nitrogen molecules or dynamite.

Atomic Force Microscopy

A visualization technology using a cantilever tip, laser, photodiode, and computer reconstruction to observe chemical structures and chemical bonds.

Adenosine

A chemical that builds up in the brain during wakefulness and binds to membrane protein receptors to trigger a cell process that induces sleep.

Caffeine

A molecule that structurally resembles adenosine and blocks adenosine receptors without triggering the chemical reaction that causes sleep.

Tolerance

A biological adaptation where cells create additional protein receptors in response to ongoing receptor blockade by a substance like caffeine.

Reactants

The starting chemical materials that enter into a chemical reaction.

Products

The ending chemical materials produced by a chemical reaction.

Activation Energy

The initial energy required to break existing chemical bonds in reactants to start a chemical reaction.

Forward Reaction

The pathway of a chemical reaction that converts reactants into products.

Reverse Reaction

The pathway of a chemical reaction that converts products back into reactants.

Chemical Equilibrium

The state where forward and reverse chemical reactions occur at the exact same rate.

Exothermic Reaction

A chemical reaction that releases energy, such as heat or light, to its surroundings.

Endothermic Reaction

A chemical reaction that absorbs energy or heat from its surroundings.