Excelsior Chemistry Unit 8

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Hydrocarbons
The simplest organic compounds containing only carbon and hydrogen. Methane and Ethane are the simplest hydrocarbons. Because carbon has four valence electrons, a carbon atom always forms four covalent bonds. They are non-polar molecules because the electron pair is shared almost equally in all the bonds.
Homologous Series
Constant increments of change in the molecular structure from one compound in the series to another of straight-chain alkanes. See the table on page 695 of your textbook or the image attached here.
Alkynes
Hydrocarbons that contain one or more carbon-carbon triple covalent bonds. Ethyne is the simplest alkyne gas.
Structural Isomers
Compounds that have the same molecular formula or composition, but the atoms are joined together in a different order, or structure. They differ in physical properties such as boiling point and melting point. They also have different chemical reactivities.
cis configuration
The methyl groups are on the same side of the double bond.
Cells
The fundamental unit of life
Prokaryotic vs. Eukaryotic
Prokaryotics are older and does not have organelles or a nucleus.
Photosynthesis
A light capturing system that converts the energy from light along with Carbon Dioxide and water to create glucose and oxygen.
Amino Acids
Any compound that contains an amino group NH2 and a carboxyl group COOH in the same molecule is an amino acid. They also include one Hydrogen atom and an R group which acts as a side chain and accounts for the differences in properties among the 20 amino acids.
Enzymes
Enzymes are proteins that act as biological catalysts as they increase the rates of chemical reactions in living things.
Cellular Respiration
The opposite of Photosynthesis. This reaction breaks down glucose and oxygen to get carbon dioxide, water, and energy.
Lipids
Lipids tend to dissolve readily in organic solvents however, they are insoluble in water. This property sets them apart from most biological substances such as carbohydrates and proteins.
Triglycerides
Triglycerides are natural fats and oils that exist three fatty acids connected to a glycerol, which are long-chain carboxyl acids. They are important as the long-term storage form of energy in the human body.
Radioactivity
Nuclear reactions account for radioactivity, and an unstable nucleus gains stability by undergoing changes. These changes are always accompanied by the emission of large amounts of energy as it decays.
Alpha Radiation
Alpha radiation consists of helium nuclei that have emitted alpha particles containing two protons and two neutrons and has a double positive charge. When an atom loses an alpha particle, the atomic number of the product atom is lower by two and the mass number is lower by four.
Beta Particle
An electron resulting from the breaking apart of a neutron in an atom.
Gamma Radiation
A high-energy photon emitted by a radioisotope is called a gamma ray, or high energy electromagnetic radiation. Gamma rays are extremely penetrating and can be very dangerous.
Band of Stability
The stability of a nucleus depends on the neutron to proton ratio as defined by an area on a graph known as the band of stability. For elements of low atomic number, this ratio is about 1. Above atomic number 20, stable nuclei have more neutrons than protons.
Half-life
The time required for one-half of the nuclei of all types of radioisotope samples to decay to products. They can be short as a fraction of a second or as long as billions of years.