Fourty Vocab

• absolute temperature: This is a temperature reading made relative to absolute zero. We use the unit of Kelvins for these readings.
• absolute zero: This is the lowest temperature possible. If you remember that temperature is a measurement of how much atoms move around in a solid, you can guess that they stop moving entirely at absolute zero. In reality, bonds still vibrate a little bit, but for the most part you don't see much happening.
• acid: This is anything that gives off H+ ions in water. Acids have a pH less than 7 and are good at dissolving metals. They turn litmus paper red and phenolphthalein colorless.
• addition reaction: A reaction where atoms add to a carbon-carbon multiple bond.
• adsorption: When one substance collects of the surface of another one.
• alcohol: An organic molecule containing an -OH group
• aldehyde: An organic molecule containing a -COH group
• alkali metals: Group I in the periodic table.
• alkaline earth metals: Group II in the periodic table.
•  alkane: An organic molecule which contains only single carbon-carbon bonds.
• alkyne: An organic molecule containing at least one C-C triple bond.
• allotropes: When you have different forms of an element in the same state The relationship that white phosphorus and red phosphorus have to each other is that they're allotropes.
• alloy: A mixture of two metals. Usually, you add very small amounts of different element to make the metal stronger and harder.
• alpha particle: A radioactive particle equivalent to a helium nucleus (2 protons, 2 neutrons)
• amphoteric: When something is both an acid and a base. Sounds familiar,
• anode: The electrode where oxidation occurs. In other words, this is wher electrons are lost by a substance.
• aqueous: dissolved in water
• atomic mass unit (a.m.u.): This is the smallest unit of mass we use in chemistry, and is equivalent to 1/12 the mass of carbon-12. To all intents and purposes, protons and neutrons weigh 1 a.m.u..
• Aufbau principle: When you add protons to the nucleus to build up th elements, electrons are added into orbitals.
• Avogadro's Law: If you've got two gases under the same conditions on temperature, pressure, and volume, they've got the same number of particles (atoms or molecules). This law only works for ideal gases, none of which actually exist..
• beta particle: A radioactive particle equivalent to an electron.
• binding energy: The amount of energy that holds the neutrons and proton together in the nucleus of an atom. It's a lot of energy, which is why you don'tsee nuclei falling apart all over the place.
• bond energy: The amount of energy it takes to break one mole of bonds.
• Bronsted-Lowry acid: Acids donate protons [H+ ions] and bases grab them
• buffer: A liquid that resists change in pH by the addition of acid or base.  consists of a weak acid and it's conjugate base (acetic acid and sodium acetate, for example).
• calorimetry: The study of heat flow. Usually you'd do calorimetry to find the heat of combustion of a compound or the heat of reaction of two compounds.
• catalyst: A substance that speeds up a chemical reaction without being used up by the reaction. Enzymes are catalysts because they allow the reactions that take place in the body to occur fast enough that we can live.
• cathode: The electrode in which reduction occurs. Reduction is when a compound gains electrons.
• chain reaction: A reaction in which the products from one step provide thereagents for the next one. This is frequently referred to in nuclear fission(when large nuclei break apart to form smaller ones) and in free-radical reactions.
• Charles's Law: The volume of a gas at constant pressure is directly proportional to the temperature. In other words, if you heat something up, it gets big.
• coagulation: When you destroy a colloid by letting the particles settle out.
• colloid: It's a suspension.
• concentration: A measurement of the amount of stuff (solute) dissolved in a liquid (solvent). The most common concentration unit is molarity (M), which is equal to the number of moles of solute divided by the number of liters of solution..
• conjugate acid: The compound formed when a base gains a proton (hydrogen atom).
• conjugate base: The compound formed when an acid loses a proton (hydrogen atom).
• covalent bond: A chemical bond formed when two atoms share two electrons..
• decomposition: When a big molecule falls apart to make two or more little ones.
• diffusion: When particles move from areas of high concentration to areas of low concentration. For example, if you open a bottle of ammonia on one end of the room, the concentration of ammonia molecules in the air is very high on that side of the room. As a result, they tend to migrate across the room, which explains why you can smell it after a little while. Be careful not to mix this up with effusion (see definition)
• dilution: When you add solvent to a solution to make it less concentrated.
• dipole moment: When a molecule has some charge separation (usually because the molecule is polar), it's said to have a dipole moment.
• dipole-dipole force: When the positive end of a polar molecule becomes attracted to the negative end of another polar molecule.
• dissociation: When water dissolves a compound.
• distillation: This is when you separate a mixture of liquids by heating it up. The one with the lowest boiling point evaporates first, followed by the one with the next lowest boiling point, etc.
• electrolysis: When electricity is used to break apart a chemical compound.
• electrolyte: An ionic compound that dissolves in water to conduct electricity.Strong electrolytes break apart completely in water; weak electrolytes only fallapart a little bit.
• electron affinity: The energy change that accompanies the addition of a electron to an atom in the gas phase.
• empirical formula: A reduced molecular formula. If you have a molecular formula and you can reduce all of the subscripts by some constant number, the result is the empirical formula.
• emulsion: When very small drops of a liquid are suspended in another. Anexample of an emulsion is salad dressing after you've shaken it up..
• endothermic: When a process absorbs energy (gets cold).
• enthalpy: A measurement of the energy content of a system.
• ester: An organic molecule with R-CO-OR' functionality.
• exothermic: When a process gives off energy (gets hot).
• first law of thermodynamics: The energy of the universe is constant. It'sthe same thing as the Law of conservation of energy.
• fission: A nuclear reaction where a big atom breaks up into little ones. Thi is what happens in nuclear power plants.
• free energy: also called "Gibbs free energy", it's the capacity of a system to do work.
• free radical: An atom or molecule with an unpaired electron. They're way reactive.
• functional group: A generic term for a group of atoms that cause a molecul to react in a specific way. It's really common to talk about this in organic chemistry, where you have "aldehydes, carboxylic acids, amines" and so on.
• gamma ray: High energy light given off during a nuclear process. When a nucleus gives off this light, it goes to a lower energy state, making it more stable.
• geometrical isomer: isomerism where atoms or groups of atoms can take up different positions around a double bond or a ring. This is also called cistrans- isomerism.
• ground state: The lowest energy state possible for an electron.
• group: A column (the things up and down) in the periodic table. Elements in the same group tend to have the same properties. These are also called "families"..
• half-reaction: The oxidation or reduction part of a redox reaction.
• halogen: The elements in group 17. They're really reactive.
• Hess's Law: The enthalpy change for a change is the same whether it take place in one big step or in many small ones.
• hybrid orbital: An orbital caused by the mixing of s, p, d, and f-orbitals.
• hydration: When a molecule has water molecules attached to it.
• hydrocarbon: A molecule containing carbon and hydrogen.
• hydrogen bond: The tendency of the hydrogen atom stuck to an electronegative atom to become attracted to the lone pair electrons on another electronegative atom. It's a pretty strong intermolecular force, which explains why water has such a high melting and boiling point.
• hydrogenation: When hydrogen is added to a carbon-carbon multiple bond.
• hydronium ion: The H+ ion, made famous by acids.
• hydroxide ion: The OH- ion, made famous by bases.