CHEM 1011 Classes of Chemical Reactions

Safety Put on Goggles And Apron

Chemical Reaction Reactants → Products Products’ characteristics and properties differ from reactants’

Four Reaction Types Combination Decomposition Single Replacement (Substitution) Double Replacement (Metathesis)

Combination Reactions Two elements react to form a compound A + B → AB e.g., 2Na (s) + Cl 2 (g) → 2NaCl (s)

Decomposition Reactions Compound breaks down into simpler elements or compounds AB → A + B e.g., 2HgO (s) → 2Hg (l) + O 2 (g)

Single Replacement (Substitution) Replacement of one component in a compound by another AB + C → CB + A e.g, Cu (s) + 2AgNO 3 (aq) → 2Ag (s) + Cu(NO 3 ) 2 (aq) 2Mg + CO 2 → 2MgO + C

Activity Series ActivityActivity

Single Replacement (Substitution) Refer to Activity Series Chart to dictate substitution Elements cannot replace anything above them Cu (s) + AlCl 3 (aq) → No Reaction

Single Replacement (Substitution) Hydrogen can be replaced by a very active metal. e.g., Zn (s) +2HCl (aq) → ZnCl 2 (aq) + H 2 (g)

Double Replacement Reactions Two compounds react to form two different compounds AB +CD → AD + CB e.g., FeCl 3 (aq)+ 3NaOH (aq) → 3NaCl (s) + Fe(OH) 3 (aq)

Conclusions Observe energy and physical changes Balance all equations resulting in a reaction Make sure to use your activity series chart when determining if reactions occur or not