English National Curriculum - Science
Mission Objectives
Review the definition of relative atomic mass
Define the relative molecular mass
Calculate the relative formula mass (Mr) of a compound from its formula, given the relative atomic masses
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Words and meanings to learn
percentage by mass
the proportion of the total mass of a compound made up by one of its elements, expressed as a percentage
relative atomic mass (Ar)
the average mass of an atom of an element compared with one-twelfth of the mass of a carbon-12 atom
relative formula mass (Mr)
the sum of the relative atomic masses of all the atoms in a formula
isotope
atoms of the same element with the same number of protons but different numbers of neutrons; Carbon-12 and Carbon-13 are examples of isotopes
compound
a substance formed when two or more elements are chemically bonded together
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