Chemistry C3 Part 3

Based on Edexcel textbook

pg 98-99 Counting Formulae

There are diiferent types of molecules that need their formula mass to be worked out. The formula of most elements is their symbol representing a single atom. The formula of elements with diatomic molecule represents the molecule. The formula of most convalent compounds represents the formula of a molecule. The formula of an ionic compound shows the ratio of ions present. The relative masses of atoms are compared using relative atomic masses. These show how much heavier something is compared to a hydrogen atom. The relative formula mass of an atom or molecule is found by adding all the relative atomic masses together.

A mole of a substance is equal to its relative formula mass in grams for example on mole of sodium carbonate equals 106g.

pg 100-101 Measuring in Moles

Mass of a substance= formula mass x number of moles

This equation is best looked at in a triangle then it is easy to reverse.

A mole of a substance is a fixed…