Chemistry 11 unit 2 - Chemical Reaction

CaCl2(aq) +KBr (aq) -KCL(aq) + CaBr2 (aq)

Always to write the right equation by using the crossover rule

This case nothing changed, so it's an NR (No Reaction)

Positive go with negative

Then check the solubility table

A double displacement will occur if the dissociated hydrated ions come out of solution

2 aqueous (aq) ionic solution = NR

This can happen in 3 ways

1) An insoluble solid (precipitate) for mass - refer to solubility table

Note precipitates, do not dissociate so are written associated in total ionic equation

Small ions with big charge tend to be insoluble because the attraction between is very strong

2) A covalent liquid (mostly H2O) is formed

A covalent gas is formed

Reflects the law of conservation of matter

How the same amount of each element on reactant and product side

H2So4+2NaOH - NaSo4+2H2O

If a polyatomic exist in the same form on both side, count them as one element

Always balance C, O2, H2, Cl2, Al last

Synthesis: A+B -AB

Decomposition: AB - A+B

Single Displacement: AB+CD - AC+BD

Double Displacement: AB+ CD -AC+BD

Combustion: Oxide creation (O2)

Oxidation - Loss of e- from an atom / more bonds to oxygen

2Mg - 2Mg^+2 = -4e- (oxidized)

Reduction - Gain of electrons from an atom/ion.. / more hydrogen bond

O2 +4e - 2O-2 (reduced

2HCl(ap)+2Na(s) - 2NaCl(aq)+H2

Na more reactive than hydrogen, so it replace H

2Na - 2Na (+1) + 2e +oxidized

2H+ + 2e - H2 (o) = reduced

2Cl- --2Cl- = spectatorion (did nothing)