Very Important Basic terms - Chemistry

Absolute zero - Absolute zero is 0K. It is the lowest possible temperature. Theoretically, at absolute zero, atoms stop moving.

Accuracy - Accuracy is a measure of how close a measured value is to its true value. For example, if an object is exactly a meter long and you measure it as 1.1 meters long, that is more accurate than if you measured it at 1.5 meters long.

Acid - There are several ways to define an acid, but they include any chemical that gives off protons or H+ in water. Acids have a pH less than 7. They turn the pH indicator phenolphthalein colorless and turn litmus paper red.

Acid anhydride - An acid anhydride is an oxide that forms an acid when it is reacted with water. For example, when SO3- is added to water, it becomes sulfuric acid, H2SO4.

Actual yield - The actual yield is the amount of product you actually obtain from a chemical reaction, as in the amount you can measure or weigh as opposed to a calculated value.

Addition reaction - An addition reaction is a chemical reaction in which atoms add to a carbon-carbon multiple bond.

Alcohol - An alcohol is any organic molecule that has an -OH group.

Aldehyde - An aldehyde is any organic molecule that has a -COH group.

Alkali metal - An alkali metal is a metal in Group I of the periodic table. Examples of alkali metals include lithium, sodium, and potassium.

Alkaline earth metal - An alkaline earth metal is an element belonging to Group II of the periodic table. Examples of alkaline earth metals are magnesium and calcium.

Alkane - An alkane is an organic molecule that only contains single carbon-carbon bonds.

Alkene - An alkene is an organic molecule that contains at least one C=C or carbon-carbon double bond.

Alkyne - An alkyne is an organic molecule that contains at least one carbon-carbon triple bond.

Allotrope - Allotropes are different forms of a phase of an element. For example, diamond and graphite are allotropes of carbon.

Alpha particle - An alpha particle is another name for a helium nucleus, which contains two protons and two neutrons. It's called an alpha particle in reference to radioactive (alpha) decay.

Amine - An amine is an organic molecule in which one or more of the hydrogen atoms in ammonia have been replaced by an organic group. An example of an amine is methylamine.

Base - A base is a compound that produces OH- ions or electrons in water or that accepts protons. An example of a common base is sodium hydroxide, NaOH.

Beta particle - A beta particle is an electron, although the term is used when the electron is emitted in radioactive decay.

Binary compound - A binary compound is one made up of two इलेमेंट्स

Binding energy - Binding energy is the energy that holds protons and neutrons together in the atomic nucleus.

Bond energy - Bond energy is the amount of energy required to break one mole of chemical bonds.

Bond length - Bond length is the average distance between the nuclei of two atoms that share a bond.

Buffer - A liquid that resists change in pH when an acid or base is added. A buffer consists of a weak acid and its conjugate base. An example of a buffer is acetic acid and sodium acetate.

calorimetry - Calorimetry is the study of heat flow. Calorimetry may be used to find the heat of reaction of two compounds or the heat of combustion of a compound, for example.

carboxylic acid - A carboxylic acid is an organic molecule containing a -COOH group. An example of a carboxylic acid is acetic acid.

catalyst - A catalyst is a substance that lowers the activation energy of a reaction or speeds it up without being consumed by the reaction. Enzymes are proteins that act as catalysts for biochemical reactions.

cathode - A cathode is the electrode which gains electrons or is reduced. In other words, it is where reduction occurs in an electrochemical cell.

chemical equation - A chemical equation is a description of a chemical reaction, including what reacts, what is produced, and which direction(s) the reaction proceeds.

chemical property - A chemical property is a property that can only be observed when a chemical change occurs. Flammability is an example of a chemical property, since you can't measure how flammable a substance is without igniting it (making/breaking chemical bonds).

Covalent bond - A covalent bond is a chemical bond formed when two atoms share two electrons.

Critical mass - Critical mass is the minimum quantity of radioactive material needed to cause a nuclear chain reaction.

Critical point - The critical point is the endpoint of the liquid-vapor line in a phase diagram, past which a supercritical liquid forms. At the critical point, the liquid and vapor phases become indistinguishable from one another