Chapter 2: The Chemical Level Of Organization Flashcards
Chemistry
The science of the structure and interactions of matter
Matter
Anything that has mass and occupies space.
(Makes up both living and non-living things)
Composed of chemical elements
96% of body mass is made up of…
- Carbon
- Hydrogen
- Nitrogen
- Oxygen
Element
A chemical substance that cannot be broken down into simpler substances.
Each element is composed of identical particles (atoms)
(92 in total, but our body only contains 24 of them)
Protons
Found in the nucleus of an atom.
Has a positive charge (p+)
Neutron
Found in the nucleus of an atom.
Has no charge (n0)
Electron
Travels around the nucleus in shells
Has a negative charge (e-)
Atom
Smallest units of matter that retains properties and characteristics of its element.
Made up of two identical particles (but has 3 subatomic particles)
Electrically neutral because it has equal number of protons and electrons (positive + negative = 0)
Isotope
Atoms of elements that differ in the number of neutrons.
Most are stable but if not they are called radioactive isotopes (will emit radiation trying to become stable)
Mass
The amount of matter in an object
(Always constant because it’s not associated with its weight)
(Properties: Solid, liquid, or gas)
Ion
When an atom becomes charged by gaining or losing an electron.
Positively charged ion = cation
Negatively charge ion = anion
Molecule
Formed when 2 (or more) atoms join by a chemical bond.
Chemical bond
Achieves complete electron shells, which allows chemical stability.
(Most stable when outer shell holds 8 electrons)
Types = ionic, covalent, hydrogen
Ionic bonds
Formed by the transfer of electrons from one atom to another.
Ex. NaCl
Covalent bond
Formed by the sharing of pairs of electrons between 2 or more atoms
2 types:
Nonpolar - electrons shared equally between atoms
Polar - electrons not shared equally between atoms
Hydrogen bond
Formed when a hydrogen atom with a partial positive charge attracts with partial negative charge of a nearby electronegative atom (usually N or O)
Chemical reactions
Occur when bonds are formed, broken, or rearranged.
(Requires reactants and products)
Can change rate of reaction with things like a catalyst, adding heat, decreasing particle size.
Compound
A substance composed of two or more elements joined by chemical bonds
Energy
The capacity to do work
2 main forms of energy:
- Potential energy
- Kinetic energy
Potential energy
Energy stored by matter due to its position.
(essentially the energy is waiting to be released)
Ex. Being at the top of the roller coaster anticipating the drop
Kinetic energy
Energy associated with matter in motion.
Ex. Going down the roller coaster
Chemical energy
A form of potential energy that is stored in the bonds of compounds and molecules.
Activation energy
Energy required to disrupt the electrons, and get the molecules to interact and form reactions.
Catalyst
(Typically an enzyme)
Speeds up reactions by lowering the activation energy.