Chemical Changes and Structures Flashcards
acid
a substance that produces hydrogen ions (H+) when dissolved in water
alkali
a soluble base that produced hydroxide ions (OH-) when dissolved in water
atom
the smallest quantity of an element. contains protons, neutrons and electrons.
atomic number
the number of protons in the nucleus of an atom of an element
base
a substance that will neutralise an acid
catalyst
a substance that will speed up a chemical reaction but is not used up in the process
compound
a substance made up of two or more elements chemically joined
concentration
a measure of how much solute is dissolve in a solvent, measured in mol l-1
covalent bond
a shared pair of electrons between (usually) two non-metal atoms
covalent network
a giant network of non-metal atoms held together by covalent bonds
dilution
addition of more solvent to a solution to decrease its concentration
dissociation
a procress in which compounds separate into oppositely charged ion
electron
a negatively charged particle with a relative mass of zero, which orbits the nucleus of an atom
element
a substance that consists of only one type of atom
enzyme
a biological catalyst
group ion
a charged particle that contains more than one type of atom (such as permanganate, MnO₄⁻)
indicator
a substance whose colour changes depending on pH
ion
a charged particle
ionic bond
the electrostatic force of attraction between positive ions and negative ions
ionic lattice
a large arrangement of ions held together by ionic bonds
isotopes
atoms with the same atomic number but different mass numbers
mass number
equal to the number of protons plus neutrons in an atom or ion
molecule
two or more atoms held together by covalent bonds
neutralisation
a reaction in which the pH moves towards 7
neutron
a neutral particle with a relative mass of 1 found in the nucleus of an atom
nucleus
the positively charged centre of an atom which contains the neutrons and protons
pH
a measure of how acidic or alkaline a substance is
proton
a positively charged particle with a relative mass of 1 found in the nucleus of an atom
rate
a measure of how quickly a chemical reaction is progressing
relative atomic mass (RAM)
the average mass of the isotopes of an element
gram formula mass (GFM)
the mass of one mole of a substance expressed in grams
spectator ion
an ion that is present as both a reactant and a product in a chemical equation, and takes no part in the reaction
tetrahedral
describes the shape of a molecule with a central atom bonded to four other atoms
valency
the number of bonds that an atom or ion can form
salt
the substance formed when the hydrogen ion in a salt is replaced by a metal ion or the ammonium ion
