definitions Flashcards
(15 cards)
diffusion
diffusion is the movement of particles from a region of higher concentration to a region of lower concentration
isotopes
isotopes are atoms of same the same element with the same number of protons and electrons but different number of neutrons
element
an element is a pure substance that cannot be broken down into simpler substances by chemical processes or by electricity
compound
a compound is a pure substance made of two or more different elements chemically combined in a fixed ratio
mixture
a mixture is made up of two or more substances that are not chemically combined
atomic mass (Ar)
the average mass of one atom of that element compared to 1/12 of the mass of one carbon-12 atom
electrolysis
electrolysis is the process of using electricity to decompose a compound
catalyst
a substance which increases the speed of chemical reaction but remains chemically unchanged at the end of the reaction. they increase the speed of reaction by providing an alternative pathway of lowered activation energy.
strong acid
dissociates completely in water to give a high concentration of H+ ions
weak acid
dissociates partially in water to give a low concentration of H+ ions
alloy
a mixture of a metal with one or a few other elements
cracking
a process where large long-chain hydrocarbons are broken up into smaller hydrocarbons which are more useful and higher in demand
macromolecule
a long chain molecule which contains a large number of monomer joined together by covalent bonds through a process called polymerisation
addition polymers
unsaturated monomers join together to form a polymer without the loss of any molecules or atoms
condensation polymers
monomers with 2 reactive functional groups join together to form a polymer with the loss of small molecules such as water
