IGCSE Chemistry Revision Notes
Topic:Stoichiometry
Sub Topic: 3-2-relative-masses-of-atoms-and-molecules
Syllabus Objectives:
CORE:
- Describe relative atomic mass, Ar , as the average mass of the isotopes of an element compared to 1/12th of the mass of an atom of 12C
- Define relative molecular mass, Mr , as the sum of the relative atomic masses. Relative formula mass, Mr , will be used for ionic compounds
- Calculate reacting masses in simple proportions. Calculations will not involve the mole concept
EXTENDED:
- Define the empirical formula of a compound as the simplest whole number ratio of the different atoms or ions in a compound
- Deduce the formula of an ionic compound from the relative numbers of the ions present in a model or a diagrammatic representation or from the charges on the ions
- Construct symbol equations with state symbols, including ionic equations
- Deduce the symbol equation with state symbols for a chemical reaction, given relevant information
