Chapter 2 Flashcards
Chemical element
A element is a substance that cannot be broken down by other substances by chemical reactions
Molecule
Two or more atoms stuck together
Compound
A substance consisting of two or more elements combined in a fixed ratio.
Subatomic particles
- Neutrons (no charge)
- Protons (+)
- Elections (-)
Atomic number
The number of protons in an element
Atomic mass
The number of neutrons plus the number of protons in the element
Isotopes
Some atoms of a given element have more or less neutrons than others, but chemically if they behave the same.
Covalent bonds
The sharing of a electron(s) to form electron pairs to make stable electron shells.
In a polar bond - unequal sharing or electron (e- spends more time orbiting one of the atoms in the bond)
In a nonpolar bond - equal sharing of electrons
Ionic bonds
The donation of an electron from one element and the receiving of that electron by another element.
Hydrogen bond
A bond that forms between a hydrogen atom bonded to a electronegative atom, and a separate electronegative atom.
Electronegativity
In a polar covalent bond, electronegativity describes the power of an atom within a molecule to attract the shared-pair electrons to itself.
(i.e. the shared electrons will spend more time orbiting the atom with higher electronegativity)
The closer the outer shell it to being full, and he more electronegative it is.
Solution
A liquid that is a mixture of two or more substances
Solvent
The dissolving agent in a solution, which is usually a liquid
(Note that water is the most common solvent known.)
Solute
A substance that is dissolved in a solution, which is often a solid
Hydrophilic
Water loving
(Attracted to the water and will dissolve in it)
Hydrophobic
Water fearing
(Will not dissolve in water)
Ex. Lipids
Cohesion
The tendency of molecules of the same kind to stick together.
(Much stronger for water than in other liquids)
Adhesion
The tendency of unlike molecules to stick to another.
Acids
Will donate H+ in aqueous solutions
[H+] > [OH-]
pH = 0-6
Bases
Will donate OH-, or (most likely) accept H+ in aqueous solutions.
[H+] < [OH-]
pH = 8-14
pH
Describe how acidic or basic a solution is. Will quantify how much H+ there is available for reactions.
(Note: every change in pH of 1 unit represents a tenfold change in the H+ of a solution)
Buffers
Solutions that resist changes in pH when an acid or base or added to them. (Will regulate the strong acid/base into a weak acid/base or neutral solution)
Matter
Anything that occupies space and has mass
Exists is 3 phases:
- solid
- liquid
- gas
Heat of vaporization
The amount of heat need to turn a given amount of liquid into a water vapour (gas)
Specific heat
The amount of heat needed to raise the temperature of 1 g of water by 1°
