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chem unit 1 module 1
definitions
Question | Answer |
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isotopes | are atoms of the same element with the same number of protons and electrons but a different number of neutrons |
atomic number | is the number of protons in the nucleus of an atom. |
mass number | is the number of protons and neutrons in the nucleus. |
relative isotopic mass | is the mass of an atom of an isoptope compared to one twelfth of the mass of an atom of carbon- 12 |
relative atomic mass | is the weighted mean mass of an atom of an element compared to one twelfth of the mass of an atom of carbon- 12 |
relative molecular mass | is the weighted mean mass of a molecule compared with one twelfth of the mass of an atom of carbon 12 |
amount of substance | is the quantity whose unit is the mole. chemists use amount of substance as a means of counting atoms |
the avogadro constant | is the number of atomsper mole of the carbon 12 isotope (6.02x10 23 mol -1 |
molar mass | is the mass per mole of a substance. the units of molar mass are g mol-1 |
a species | is any type of particle that takes part in a chemical reaction |
an acid | is a species that is a proton donor |
a base | is a species that is a proton acceptor |
hydrated | refers to a crystalline compound containing water molecules |
anhydrous | refers to a substance that contains no water molecules |
water of crystallisation | refers to water molecules that form an essential part of the crystalline structure of a compound. |
an oxidation number | is a measure of the number of electrons that an atom uses to bond with atoms of another element. |
oxidation | is a loss of electrons and an increase in oxidation number |
reduction | is a gain of electrons and a decrease in oxidation number |
redox reaction | is a reaction in which both reduction and oxidation take place. |