Basic Chem/Ph/Water practice

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur

The most common elements found in living organisms.

subatomic particles

Protons, Neutrons, Electrons

Isotope

Different forms of the same element that have different numbers of neutrons.

Ion

A charged atom that has gained or lost electrons.

Mass Number

The sum of the number of protons and neutrons in an atom.

Atomic Number

The number of protons in the nucleus of an atom.

Electronegativity

The tendency of an atom to attract electrons.

Noble Gases

The elements in the rightmost column of the periodic table that have a full outer shell of electrons and do not react with other elements.

Valence Electrons

Electrons in the outermost shell of an atom.

Ionic Bond

A bond formed when one atom donates an electron to another atom.

Covalent Bond

A bond formed when two atoms share electrons.

Polarity

Uneven distribution of electrons among atoms connected by a chemical bond.

Polar Molecule

A molecule with partially positive and partially negative charges.

Nonpolar Molecule

A molecule with an even distribution of electrons and no partial charges.

Hydrogen Bond

Weak attraction between water molecules due to the partial positive and partial negative charges.

Molecule

Two or more atoms held together by chemical bonds.

Compound

A substance made up of two or more atoms of different elements.

Chemical Change

A reaction that forms new products

Physical change

Matter changes form but not chemical identity

pH

Power of Hydrogen; a measure of hydrogen ion concentration.

Acids

Increase the hydrogen ion concentration of a water solution

Bases

Decrease the hydrogen ion concentration of a water solution.

pH Scale

Ranges from 0-14. Any pH value above 7 is a Base, any pH value below 7 is an acid.

Buffers

Any compound(s) that can both increase or decrease hydrogen ion concentration to maintain homeostasis.

Carbonic Acid

Bicarbonate Buffer System

Properties of water

Universal Solvent, Cohesion, Adhesion, High Specific Heat, High Heat of Vaporization, Density Changes

Dissociate

Compound breaks into ions in a solution

Cohesion

Water is attracted to other water molecules due to hydrogen bonding. Causes high surface tension.

Adhesion

Water is attracted to other substances that are polar/charged.

Capillary action

Water sticks to the walls of plant cell capillaries and travels up the plants

High specific heat

Water temperature changes slowly and holds temperature well.

High heat of vaporization

Water requires a lot of energy to change state.

Density Changes

Ice floats - solid water molecules form a lattice that is less dense than liquid water and therefore floats.