1.  Get a h/w page, Organization tree w/s, and a solubility rules page  Complete the Warm up at your table (Single replacement and combustion)  You will need paper and something to write with  Today we will be discussing: “How do you recognize and represent chemical changes?” Homework: Double Replacement W/S Important Dates: 4/2: Reaction Test

2.  Double Replacement Reactions:  A reaction which involves the exchange of ions between two compounds  AB + CD → AD + CB  Ca(OH) 2 (aq) + 2HCl(aq) → CaCl 2 (aq) + 2H 2 O(l)  2NaOH(aq) + CuCl 2 (aq) → 2NaCl(aq) + Cu(OH) 2 (s)

3.  All in aqueous solutions!  3 types of Double Replacement reactions  Formation of precipitate  Formation of water  Formation of a product which decomposes into a gas

4.  Solubility rules!!!!!  AB(aq) + CD(aq) → AD(aq) + CB(s)  NaCl(aq) + AgNO 3 (aq) → AgCl(s) + NaNO 3 (aq)  BaCl 2 (aq) + Na 2 SO 4 (aq) → ?  BaCl 2 (aq) + Na 2 SO 4 (aq) → BaSO 4 (s) + 2NaCl(aq)  Na 2 SO 4 (aq) + CaCl 2 (aq) → ?  Na 2 SO 4 (aq) + CaCl 2 (aq) → CaSO 4 (s) + NaCl(aq)

5.  Between Acids and Bases (H + /OH - )  HX(aq) + YOH(aq) → XY(aq) + H 2 O(l)  HCl(aq) + NaOH(aq) → NaCl(aq) + H 2 O(l)  H 2 SO 4 (aq) + Mg(OH) 2 → ?  H 2 SO 4 (aq) + Mg(OH) 2 → MgSO 4 (aq) + H 2 O(l)  H 3 PO 4 (aq) + KOH → ?  H 3 PO 4 (aq) + KOH → K 3 PO 4 + H 2 O(l)

6.  Three products will decompose into gasses:  H 2 CO 3 → CO 2 (g) + H 2 O(l)  NH 4 OH → NH 3 (g) + H 2 O(l)  H 2 SO 3 → SO 2 (g) + H 2 O(l)  CaCO 3 (s) + HCl(aq) → H 2 CO 3 (aq) + CaCl 2 (aq)  NaOH(aq) + NH 4 Br(aq) → NaBr(aq) + NH 4 OH(aq) H 2 CO 3 → CO 2 (g) + H 2 O(l) NH 4 OH → NH 3 (g) + H 2 O(l)

7.  Some DR can create gases without decomposition of a product  Not very common, but they do occur  HCl(aq) + FeS(s) → FeCl 2 (aq) + H 2 S(g)  NaCN(aq) + HCl(aq) → NaCl(aq) + HCN(g)

8.  AsCl 3 (aq) + H 2 S(aq) → ?  2AsCl 3 (aq) + 3H 2 S(aq) → As 2 S 3 (s) + 6HCl(aq)  HCl(aq) + CaCO 3 (aq) → ?  2HCl(aq) + CaCO 3 (aq) → CO 2 (g) + CaCl 2 (aq) + H 2 O(l)  FeCl 3 (aq) + NaOH(aq) → ?  FeCl 3 (aq) + 3NaOH(aq) → Fe(OH) 3 + 3NaCl(aq)  H 2 SO 4 + KOH → ?  H 2 SO 4 + 2KOH → 2H 2 O(l) + K 2 SO 4 (aq)  HNO 3 + Ca(CN) 2 →?  2HNO 3 + Ca(CN) 2 →2HCN + Ca(NO 3 ) 2