Advertisement Upgrade to remove ads


anything that has mass and takes up space


a measure of the amount of matter in an object


a substance that cannot be separated or broken down into simpler substances by chemical means


the smallest unit of an element that maintains the chemical properties of that element.


an atoms central region, which is made up of protons and neutrons


has a positive charge and is located in the nucleus of an atom


has no charge

atomic number

the number of protons in the nucleus of an atom

mass number

the sum of number of protons and neutrons in the nucleus of an atom


a subatomic particle that has a negative charge


a region in an atom where there is a high probability of finding electrons


an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons


a substance made up of atoms of two or more different elements joined by chemical bonds

chemical bond

the attractive force that holds ions or atoms together

covalent bond

a bond formed when atoms share one or more pairs of electrons


a group of atoms that are held together by chemical forces; smallest unit of matter


an atom, radical, or molecule that has gained or lost one or more electrons and has a poitive or negative charge

ionic bond

the attractive force between oppositely charged ions which form when electrons are transferred from one atom to another


the capacity to do work

chemical reaction

the process by which one or more substances changes to produce one or more different substances


a substance or molecule that participates in a chemical reaction


a substance that forms in a chemical reaction


the sum of all chemical processes that occur in an organism

activation energy

the minimum amount of energy required to start a chemical reaction


a substance that changes the rate of a chemical without being consumed or changed significantly


a type o protein or RNA molecule that speeds up metabolic reactions in plants and animals without being permnently changed or destroyed

redox reaction

the reaction in which electrons are transferred between atoms

oxidation reaction

a chemical reaction in which a reactant loses one or more electrons such that the reactant becomes more positive in charge

reduction reaction

a chemical change in which electrons are gained, either by removal of oxygen, the addition o hydrogen, or the additive of electrons


describes a molecule with opposite charges on opposite ends

hydrogen bond

the intermolecular force occurring when a hydrogen atom that is bonded to a highly electronegative atom of one molecule is attracted to two unshared electrons of another molecule


the force that holds molecules of a single material together


the attractive force between two bodies of different substances that are in contact with eachother


a tiny blood vessel that allows an exchange between bonds and cells in tissue


a homogeneous mixture throughout which two or more substances are uniformily dispersed


in a solution, the substance that dissolves the solvent


in a solution, the substance in which the solute dissolves


the amount of a particular substance in a given quantity of a mixture , solution, or ore

saturated solution

a solution that cannot dissolve any more solute under the given conditions

aqueous solution

a solution in which water is the solvent

hydroxide ion

the OH(negative) ion

hydronium ion

an ion consisting of a proton combined with a molecule of water H(3)O(positive)


any compound that increases the the number of hydronium ions when dissolved in water


any compound that increases the number hydroxide ions when dissolved in water

pH scale

a range of values that are used to express the acidity or basicity of a system low numbers are acidic, high numbers are basic


a solution made from a weak acid and its conjugate base that neutralizes small amounts of acids or bases added to it

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording