The general form of a direct combination reaction is : A + B → AB where A and B are elements or compounds , and AB is a compound consisting of A and B. Examples of combination reactions include : 2Na + Cl2 → 2NaCl ( formation of table salt ) S + O2 → SO2 ( formation of sulfur dioxide ) 4Fe + 3O2 → 2Fe2O3 ( iron rusting ) CO2 + H2O → H2CO3 ( carbon dioxide dissolving and reacting with water to form carbonic acid ) 4 special synthesis rules : metal-oxide + H2O → metal ( OH ) non-metal-oxide + H2O → oxi-acid metal-chloride + O2 → metal-chlorate metal-oxide + CO2 → metal carbonate ( CO3 )
The chemical equation for a direct combination reaction is : A + B → AB where A and B are elements or compounds , and AB is a compound consisting of A and B. Examples of combination reactions include : 2Na + Cl2 → 2 NaCl ( formation of table salt ) S + O2 → SO2 ( formation of sulfur dioxide ) 4 Fe + 3 O2 → 2 Fe2O3 ( iron rusting ) CO2 + H2O → H2CO3 ( carbon dioxide dissolving and reacting with water to form carbonic acid ) Four special synthesis rules are : metal-oxide + H2O → metal ( OH ) non-metal-oxide + H2O → oxi-acid metal-chloride + O2 → metal-chlorate metal-oxide + CO2 → metal carbonate ( CO3 )