Topic 1: Chemical Bonding and Water

Covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Buffer

A solution that minimizes changes in pH when extraneous acids or bases are added to the solution.

Covalent nonpolar bond

Bond where atoms share electrons equally; ex: O2

Covalent polar bond

Bond where atoms share electrons unequally; ex: H2O

Explain how atoms interact via covalent and ionic bonds

Covalent bonding involves the sharing of electrons between two or more atoms. Ionic bonds form when two or more ions come together and are held together by charge differences

Explain the difference between polar and nonpolar covalent bonds

Polar means there is unequal sharing of electrons, while nonpolar means equal sharing.

Base

a compound that produces h- ions in solution

Acid

any compound that forms H+ ions in solution

Explain why water is an ideal solvent for biological systems, with reference to properties derived from its ability to form hydrogen bonds.

due to its unique ability to form hydrogen bond allows water to dissolve many substances, facilitate chemical reactions, stabilize biomolecular structures (like proteins and nucleic acids), and maintain a relatively constant temperature in living organisms.

Explain how the existence of polar covalent bonds allows molecules to interact via h bond

he partial positive charge of the hydrogen atoms of one molecule are attracted to the partial negative charge of an atom of a nearby molecule.

pH

hydrogen ion concentration

Ionic bond

the attraction between oppositely charged ions (LiF)

Explain the importance of buffers in biological systems.

the solution of reserve acidity or alkalinity which resists change of pH upon the addition of a small amount of acid or alkali.

Hydrophobic

water hating

Hydrophilic

water loving

Hydrogen bond

weak attraction between a slightly positive hydrogen atom and a slightly negative atom.

Explain the meaning of the pH scale as it relates to the concentration of protons in a solution

where lower pH values correspond to higher proton concentrations (indicating greater acidity) and higher pH values correspond to lower proton concentrations (indicating greater alkalinity).