Dojo Study Club (The ULTIMATE Pure Chemistry Definitions Booklet)

Definitions (Pure Chemistry) D o j o E d u c a t i o n

Relative Atomic Mass (Ar) The average mass of one atom of an element when compared with 1/12 the mass of one atom of carbon-12. Relative Molecular Mass (Mr) The average mass of one molecule of a substance when compared with 1/12 the mass of one atom of carbon-12. Mole One mole of a substance contains the same number of particles as the number of atoms in 12 grams of carbon-12. Molar Mass The mass of one mole of any substance. Avogadro’s Law Avogadro’s Law states that equal volumes of all gases, under the same temperature and pressure contain the same number of particles. Empirical Formula Empirical formula shows the simplest ratio of the different types of atoms in a compound. Molecular Formula Molecular formula shows the exact number of each element in a compound. Structural Formula Structural formula shows how the atoms are joined together in a compound. Limiting Reactant The limiting reactant is the reactant that is completely used up in a reaction and it limits the amount of products formed. Mole Concept @dojoeducation

Element An element is a pure substance that cannot be broken down into simpler substances by chemical means. Compound A compound is a pure substance that contains two or more different elements, chemically combined together. Mixture A mixture contains two or more substances that are not chemically combined together. Molecule A group of two or more atoms that are chemically combined. Atom The smallest particles of an element. Isotope An isotope is an atom of the same element with different number of neutrons, but same number of protons an electrons Proton Number The number of protons in the atom. Nucleon Number The number of protons and neutrons in the atom. Atomic Structure @dojoeducation

Ionic Bond Strong electrostatic force of attraction between oppositely charged ions. Covalent Bond Bond formed by the sharing of at least one pair of valence electrons between atoms. Giant Ionic Lattice Large number of oppositely charged ions arranged in a repetitive, orderly manner, held in place by strong ionic bonds Simple Molecular Structure Small molecules with strong covalent bonds within the molecule, but weak intermolecular forces of attraction between molecules. Chemical Bonding @dojoeducation

Acid A substance that produces H+ ions when dissolved in water. Base Any metal oxide or hydroxide that reacts with an acid to produce a salt and water only. Alkali A substance that produces OH- ions when dissolved in water. Strong Acid An acid that dissolves in water to produce a high concentration of H+ ions. Weak Acid An acid that dissolves in water to produce a low concentration of H+ ions. Salt A salt contains a positive metal ion (or ammonium ion) and a negative non- metal ion. Acids & Bases @dojoeducation

Redox Reaction A reaction in which both reduction and oxidation take place. Oxidation A substance in oxidised when it gains oxygen in a chemical reaction. Reduction A substance