Experiencing Chemistry Glossary

A

• acid
  a compound that increases the number of hydrogen ions (H+) in solution with water All acids have a pH below 7

• amino acid
  the building block of a protein; these molecules may be joined together in long chains to form proteins

• antioxidant
  a compund that prevents the oxidation of substances in food or the body

• atom
  a very, very small particle that makes up all matter

B

• base
  a compound that decreases the number of hydrogen ions (H+) in solution with water; all bases have a pH above 7

• biochemistry
  the study of chemical reactions that occur within living things

C

• calorie
  energy

• carbohydrate
  a sugar or combination of sugars

• catalyst
  a substance that helps chemical reactions to occur but is not changed in the reaction

• chemical
  anything that uses space and has mass

• chemical bond
  a connection that holds two or more atoms or molecules together

• chemical reaction
  when elements or compounds interact to form new elements or compounds

• cholesterol
  a white, waxy substance found in animal fat, blood, and nerve tissue; if too much cholesterol is present in the blood vessels that nourish your heart, it can cause heart disease

• chromatography
  a technique used by biochemists to separate and identify biological molecules by comparing the rate of travel on paper of different molecules

• compound
  a substance made of two or more elements chemically bonded together

• concentration
  the relative amount of a particular atom or molecule in a solution; a large amount is a high concentration; a small amount is a low concentration

• crystal
  a solid that has a regular pattern of atoms or molecules

D

• density
  a description of the amount of matter in a substance in relation to its volume

• DNA
  deoxyribonucleic acid; this biological molecule forms the "blueprint" for life

E

• electrochemistry
  chemical reactions that use or generate electricity or electrical charges

• electrolysis
  a process in which electricity is used to separate elements in a molecule

• electron
  a tiny, negatively charged particle found in atoms

• electrophoresis
  a technique used by biochemists to separate and identify large biological molecules by using electric current

• electroplating
  a process in which electricity is used to coat one metal onto the surface of another metal

• element
  a substance made of all the same type of atoms

• endothermic reaction
  a chemical reaction that absorbs heat and feels cold

• enzyme
  a complex protein substance produced in living cells that causes or accelerates chemical reactions in other substances in an organism without being permanently charged itself--a catalyst

• equilibrium
  a point reached during a chemical reaction when no further overall changes occur

• exothermic reaction
  a chemical reaction that gives off heat and feels hot

G

• gas
  a state of matter in which the molecules or atoms are very far apart and move very fast

I

• indicator
  a chemical that changes color with changes in pH

• ion
  an atom or molecule with an electrical charge

L

• liquid
  a state of matter in which the molecules or atoms are close together but also move around each other

M

• metal
  a type of substance that often has a shiny surface, is able to be shaped, and conducts heat and electricity well

• miscibility
  the ability of a substance to dissolve in another substance

• mixture
  two or more elements and/or compounds that are mixed together but are not chemically bonded

• molecule
  a small particle made of two or more atoms that are chemically bonded together

N

• nutrients
  chemical substances in food that nourish the body by providing energy and building materials

O

• oxidation
  a chemical process in which a substance loses electrons (often accompanied by the gain of an oxygen atom)

P

• periodic table
  a chart that groups the elements by similar properties and structures

• pH
  a scale that measures relative acidity and basicity

• photochemistry
  chemical processes that use light energy

• physical state of matter
  the form a substance takes, based on the behavior of its molecules or atoms: solid, liquid, or gas

• pollutant
  a chemical that is unwanted in a particular environment

• polymer
  a large molecule that is made of many smaller molecules linked together

• protein
  a complex biological molecule that may act as a structural element or may assist biochemical reactions

R

• recycle/recycling
  using a substance or parts of a substance more than once

• reduction
  a chemical process in which a substance gains electrons (the opposite of oxidation)

• reversibility
  the ability of a chemical reaction to return to its pre-reaction state

S

• solid
  a state of matter in which the molecules or atoms are close together and form a rigid structure

• soluble/solubility
  the ability of a substance to dissolve in another substance

• solution
  a completely uniform mixture

• starch
  a complex carbohydrate; a starch molecule is made of lang chains of simple sugar molecules

• sugar
  an important type of biological molecule that helps provide energy for living things

T

• toxin
  a chemical that is harmful to living things