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atom

(physics and chemistry) the smallest component of an element having the chemical properties of the element

acid

any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt

adhesion

the property of sticking together (as of glue and wood) or the joining of surfaces of different composition

amino acid

basic building blocks of protein molecules

anion

a negatively charged ion

atomic nucleus

an atom's dense central core, containing protons and neutrons.

atomic number

the number of protons in the nucleus of an atom

atomic mass

(chemistry) the mass (in atomic mass units) of an isotope of an element

aqueous solution

a solution in water

base

any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water

buffer

an ionic compound that resists changes in its pH

calorie

unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure

carbonyl group

an organic molecule, a functional group consisting of a carbon atom linked to a double bond to an oxygen atom C=O

carboxyl group

A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group. -COOH

cation

a positively charged ion

chemical equilibrium

in a reversible chemical reaction, the point at which the rate of the forward reaction equals the rate of the reverse reaction.

cohesion

(physics) the intermolecular force that holds together the molecules in a solid or liquid

compound

(chemistry) a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight

covalent bond

a chemical bond that involves sharing a pair of electrons between atoms in a molecule

double bond

a chemical bond formed when atoms share two pairs of electrons

electron

negatively charged particle; located outside the atomic nucleus

electron shell

An energy level representing the distance of an electron from the nucleus of an atom.

electronegative

the ability of an atom of an element to attract electrons when the atoms is in a compound

element

any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter

energy

(physics) the capacity of a physical system to do work

energy level

place in an atom where an electron is most likely to be found

evaporative cooling

the property of a liquid whereby the surface becomes cooler during evaporation, owing to a loss of highly kinetic molecules to the gaseous state.

functional group

group of atoms within a molecule that interacts in predictable ways with other molecules

heat

a form of energy that is transferred by a difference in temperature

heat of vaporization

heat absorbed by a unit mass of a material at its boiling point in order to convert the material into a gas at the same temperature

hydration shell

The sphere of water molecules around each dissolved ion

hydrocarbon

an organic compound containing only carbon and hydrogen

hydrogen bond

a chemical bond consisting of a hydrogen atom between two electronegative atoms (e.g., oxygen or nitrogen) with one side be a covalent bond and the other being an ionic bond

hydrogen ion

a positively charged atom of hydrogen

hydrophilic

having a strong affinity for water

hydrophobic

lacking affinity for water

hydroxyl group

the monovalent group -OH in such compounds as bases and some acids and alcohols

hydroxide ion

OH-

ion

a particle that is electrically charged (positive or negative)

ionic bond

a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains to electron to form a negative ion

ionic compound

a compound that consists of positive and negative ions

isomers

compounds with the same formula but different structure

isotope

one of two or more atoms with the same atomic number but with different numbers of neutrons

Joule

a unit of electrical energy equal to the work done when a current of one ampere passes through a resistance of one ohm for one second

kinetic energy

energy of motion

mass number

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

matter

that which has mass and occupies space

methyl group

A chemical group consisting of a carbon bonded to three hydrogen atoms. The methyl group may be attached to a carbon or to a different atom. -CH3

molecular formula

a chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms.

molecule

(physics and chemistry) the simplest structural unit of an element or compound

Mole

the molecular weight of a substance expressed in grams

molarity

concentration measured by the number of moles of solute per liter of solvent

neutron

an elementary particle with 0 charge and mass about equal to a proton

nonpolar covalent bond

a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge

orbital

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

organic chemistry

the chemistry of compounds containing carbon (originally defined as the chemistry of substances produced by living organisms but now extended to substances synthesized artificially)

pH

a value that indicated the acidity or alkalinity of a solution on a scale of 0-14, based on the proportion of H+ ions.

phosphate group

a functional group consisting of a phosphorus atom covalently bonded to four oxygen atoms

polar covalent bond

a covalent bond in which electrons are not shared equally

polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end

potential energy

the mechanical energy that a body has by virtue of its position

products

the elements or compounds produced by a chemical reaction

protons

Positively charged particles

radioactive isotope

isotope in which the nucleus decays (breaks down) over time, giving off radiation in the form of matter and energy

reactants

the elements or compounds that enter into a chemical reaction

solution

a homogeneous mixture of two or more substances

solute

the dissolved substance in a solution

solvent

a liquid substance capable of dissolving other substances

specific heat

the heat required to raise the temperature of one gram of a substance one degree centigrade

structural formula

an expanded molecular formula showing the arrangement of atoms within the molecule

surface tension

a phenomenon at the surface of a liquid caused by intermolecular forces

sulfhydryl group

A functional group consisting of a sulfur atom bonded to a hydrogen atom (—SH).

temperature

the average kinetic energy of the individual particles

trace element

an element that occurs at very small quantities in the body but is nonetheless important for many biological processes

valence shell

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.

valence electron

an electron in the outer shell of an atom which can combine with other atoms to form molecules

Van der Waal

weak hydrogen bonding - adhesion part of water molecule

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