Aim # 10: How can we predict the products of a chemical reaction (part 2)? H.W. # 10a Study pp. 213-223 (sec. 8.1-8.2) Ans. ques. p. 223 # 1,3 p. 245 # 7,8,10,11 Read pp. 226-229

Do Now: Given the balanced equation Ca + 2H2O → X + H2 What is the correct formula of the product X?

IV Double Replacement Reactions compound 1 + compound 2 → compound 3 + compound 4 AB + CD → AD + CB In order for a double replacement reaction to Occur, a cation and an anion must be removed from solution chemically. There are 3 ways for this to occur:

1. Formation of water This usually occurs in acid-base reactions. e.g. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) 2. Formation of a gas e.g. NaHCO3(aq) + HCl(aq) → NaCl(aq) + H2CO3(aq) but: H2CO3 → H2O(l) + CO2(g) 3. Formation of a precipitate e.g. 3NaCO3(aq) + 2AlCl3(aq) → 6NaCl(aq) +Al2(CO3)3(s)

We can predict when precipitates will form. Reference Table F Problem: K2CO3(aq) + CaCl2(aq) → ? Will these compounds react to form new ones? “Switching Partners”, K2CO3(aq) + CaCl2(aq) → 2KCl(?) + CaCO3(?) According to Ref. Table F CaCO3 is insoluble- it will precipitate! Therefore , the reaction will occur.

Predict whether the following reactions will occur Predict whether the following reactions will occur. If yes, predict the products. 1. Pb(NO3)2(aq) + NaCl(aq) → ? Ans: PbCl2(s) + NaNO3(aq) 2. NaC2H3O2(aq) + KCl(aq) → ? Ans: NO REACTION

3. A solution of silver nitrate is mixed with a solution of sodium chromate. Ans: 2AgNO3(aq) + Na2CrO4(aq) → Ag2CrO4(s) + 2NaNO3(aq) 4. A solution of nickel(II) nitrate is mixed with a solution of potassium carbonate. Ans: Ni(NO3)2(aq) + K2CO3(aq) → NiCO3(s) + 2KNO3(aq)

5. FeCl3(aq) + NaOH(aq) → Fe(OH)3(s) + NaCl(aq) 6. CuSO4(aq) + NaNO3(aq) → NO REACTION 7. (NH4)2S(aq) + CoCl2(aq) → NH4Cl(aq) + CoS(s)

8. CuSO4(aq) + Na2CO3(aq) → CuCO3(s) + Na2SO4(aq)