Vocab Unit 3 Flashcards
Atom
The smallest unit of an element that retains the chemical properties of that element.
Nucleus
The center of an atom, made of protons and neutrons.
Protons
Positively charged atomic particles weighing about 1 amu.
Neutrons
Neutrally charged atomic particles weighing about 1 amu.
Electrons
Negatively charged atomic particles weighing almost nothing- 1/1000 of an amu.
Element
A substance that cannot be broken down or separated into simpler substances by chemical means.
Molecule
Two or more atoms chemically bonded together.
Polar molecule
A molecule in which the distribution of electrons between the covalently bonded atoms is not even. For example, H2O is a polar molecule because the hydrogen atoms are positive and the oxygen atom is negative.
Energy level/electron cloud
The system of electrons that orbit the nucleus. Each level can hold a different number of electrons.
Atomic mass/weight
The number of protons and neutrons in the nucleus.
Covalent bond
Bond in which electrons between atoms are shared.
Ionic bond
Bond in which electrons are transferred from one atom to another, making one atom slightly positive and the other negative. The opposite charges attract.
Isotope
An atom with a differing number of neutrons, and therefore a differing atomic mass, that can release radiation.
Ion
An atom that gained or lost one or more electrons, giving it a slightly positive or negative charge.
Chemical reaction/equation
When chemical bonds break or form to change one substance into another.
Potential energy
Potential energy is defined as mechanical energy, stored energy, or energy caused by its position relative a zero position.
Kinetic energy
Energy from motion.
Chemical energy
The energy stored in chemical bonds between atoms and is released when the bonds are broken.
Activation energy
The minimum amount of energy required to start a chemical reaction.
Some properties of water
It is a polar molecule, it forms hydrogen bonds, cohesion, adhesion, surface tension, it is a good solvent, it has a high heat capacity, and it expands when frozen.
Hydrogen bond
A bond formed between molecules of water because of hydrogen atoms’ positive charge and oxygen atom’s negative charge. Opposite charges attract.
Surface tension
The way the molecules of a substance stick together because of their attraction to each other, allowing the liquid to typically have the least possible surface area.
Capillary action
Hydrogen bonds allowing water to stick to the sides of its container and to itself; in this way it can allow trees to get water all the way from their roots to the tops of their trunks.
High specific heat/heat capacity
It takes a lot of energy to heat up or cool down water, unlike metal and diamond.
Carbohydrate
A molecule made of saccharrides, including sugars, starches, and fiber. It is a good source of energy.
pH scale
A measurement of acidity based on the amount of free hydrogen ions in a solution. pH=power of hydrogen.
Saturated
There are no more molecules of solvent available to surround any more molecules of solute.
Ionization of water
The reaction in which water breaks into hydrogen and hydroxide ions is a dissociation reaction. When a molecular compound undergoes dissociation into ions, the reaction can also be called ionization.
H2O → H+ + OH-
Organic vs. inorganic compounds
Organic compounds are molecules associated with living organisms, typically containing carbon. Inorganic compounds are compounds which do not contain carbon and are not derived from living matter, usually geological systems instead.
Acid
A substance 0-6 on pH scale, with a large amount of
positive hydrogen ions.
Base
A substance 8-14 on pH scale, with a large amount of negative hydroxide ions.
Monosaccharides
A single basic unit of carbohydrates.
Polysaccharides
A carbohydrate whose molecules consist of more than two saccharide/sugar molecules bonded together.
Monomer
The molecular subunit of a polymer. (A molecule that can be bonded to other identical molecules to form a polymer–a long chain of monomers.)
Polymer
A large molecule formed by more than 5 monomers.
Disaccharides
A carbohydrate/sugar with molecules of exactly two monosaccharide molecules bonded together.
Catalyst
Something that speeds up chemical reactions.
Enzyme
A biological catalyst–a large protein catalyst–that lowers activation energy for reactions to occur at cell temperature.
Substrate
Whatever that specific enzyme is designed to break down.
Active site
The specific place on an enzyme where it binds to the substrate.
Coenzyme
Things that help the enzyme bind to a substrate. Example: Vitamins!
Denaturation
The disruption of hydrogen bonds between amino acids, cause by extreme temperatures, pH, or salinity. (Can sometimes be reversible.)
Lipid
Fats/oils made from fatty acids, important for long term energy and cell membranes.
Saturated vs. unsaturated fat
Saturated means each carbon is connected to a hydrogen, single bonds, glycerol backbone with a triglyceride attached. Unsaturated means there is not as much hydrogen and there are double bonds.
Protein
Made of amino acids, important for structure.
Nucleic acid
Made of nucleotides, helps with cell control and heredity.
Solution
A mixutre of a solute and a solvent.
Solvent
What the solute dissolves in.
Solute
The thing that dissolves in the solvent.
