Bio 1113 Ch. 2- Basic Chemistry terms

Terms and concepts from Chapter 2

Atom

Smallest piece of an element that can still retain characteristics of that element.

Mass Number

Protons + Neutrons

How many electrons can the first and second shell of an orbital hold consecutively?

First: 2 electrons

Seconds: 8 electrons

Chemical Bond

An attractive force that holds atoms together and links them into molecules.

Covalent bonds ____ electrons.

share

Ionic bonds _____ electrons.

steal

Electronegativity

The strength with which atoms pull electrons toward themselves.

Polar bonds are created by _____.

Having an electronegativity above 0.4.

Ionic Bond is a ____

bond between a cation and an anion.

Molecular shape is _____?

crucial in determining how biological molecules specifically recognize and respond to one another.

The _____ on the hydrogen atom of one water molecule _____ the _____ on the oxygen of a neighboring water molecule.

slight positive charge; attracts; slight negative charge

The __________ that hold water molecules together give water a collection of _________.

Hydrogen bonds; important unique properties

Hydrophilic

In terms of water as an efficient solvent, these are water loving molecules. Ions and polar molecules stay in solution due to their interactions with water’s partial charges.

Hydrophobic

In terms of water as an efficient solvent, these are water fearing molecules. they are uncharged and non-polar compounds that do not dissolve in water.

Hydrophobic interactions

When Hydrophobic molecules interact with each other, after being forced close to avoid water.

Cohesion

Attraction between like molecules.

Adhesion

Attraction between unlike molecules.

Water is ________ because of __________

cohesive/stays together; hydrogen bonds

Surface Tension

Cohesive forces caused by attraction between molecules at surface of liquid.

Ice is ________ than liquid water.

Less dense (because of the lack of crystal lattices in liquid)

Water resists changing its _________.

temperature (cools and heats very slowly)

Concepts in ‘high specific heat’

vaporization/ evaporation

Concepts in ‘solvent of life’

hydrophilic/hydrophobic/solubility

Reduced density in a solid vs a liquid

solid ice is less dense than liquid water

Water and acid base reactions?

Sometimes water molecules break into two pieces, separating the H atom from the molecule. Since protons (H+) don’t exist by themselves, they associate with another water molecule; dissociation reaction produces hydronium ions (H3O+)

pH scale

Expresses proton concentration (H+) in a solution.

Acids

substances that give up protons during chemical reaction. Have a pH of less than 7.

Bases

substances that acquire protons during chemical reaction. Have a pH of greater than 7.

Does adding Acid to a solution increase or decrease proton concentration of a solution?

Increase

Carbon provides a ______________?

Molecular skeleton

Organic Molecule

Molecule that contains carbon bonded to other elements; linked in a chain or ring.

Isomers

Compounds with the same molecular formula but different structures and properties

Enantiomers

Isomers that are mirror images of each other but potentially have different effects.