Untitled - Kelly Walsh High School

Aqueous Solutions 53
Don’t Forget!
Write the formulas for the reactants:
Pb(NO 3) 2(aq) KI(aq)
We need to know which ions are available. To do this, it will be helpful to break
apart any ionic reactants into their constituent ions:
Pb 2 (aq) 2 NO 3 – (aq) K (aq) I – (aq)
Next, in order to predict possible products we must consider all possible combinations
of cations with anions. Predict the possible products by combining the cation
of one reactant with the anion of the other and vice versa. In this case, we get:
PbI 2 KNO 3
You will never get a compound containing only cations or only anions.
Apply the solubility rules to the two possible products:
PbI 2(s) Insoluble, therefore a precipitate will form
KNO 3(aq) Soluble, no precipitate will form
Write the chemical equation by adding the predicted compounds to the product
side, and balance the resultant equation:
Pb(NO 3) 2(aq) 2 KI(aq) l PbI 2(s) 2 KNO 3(aq)
If neither possible products were insoluble, then no precipitation reaction
would occur. The solution would be a mixture of all the ions. Situations where
“no reaction” occurs are often labeled NR.
4-3 Acids, Bases, and Neutralization
Acids and bases are extremely common substances, as are their reactions with
each other. At the macroscopic level, acids taste sour (that is, lemon juice) and
react with bases to yield salts. Bases taste bitter (that is, tonic water) and react
with acids to form salts.