Quiz 3/30/05 In a group of 2 Active metal oxides react with water to form hydroxides. ex: 1. Na 2 O + H 2 O  ________ Halogens react with metals to form salts 2. Mg + Cl 2  _____ Metals react with oxygen to form oxides 3. K + O 2  ______ Substances may decompose when exposed to electricity: 4. NaCl  ____ + _____ metal carbonates decompose to form metal oxides and carbon dioxide. 5. Al 2 (CO 3 ) 3  ___________+ __________ metal hydroxides decompose to form metal oxides and water. 6. Mg(OH) 2  _________ + _________ Lab 30 tomorrow! Please do pre-lab and summary

Quiz 3/30/05 Answers Active metal oxides react with water to form hydroxides. ex: 1. Na 2 O + H 2 O  2 NaOH_ Halogens react with metals to form salts 2. Mg + Cl 2  MgCl 2 Metals react with oxygen to form oxides 3. 4 K + O 2  2 K 2 O Substances may decompose when exposed to electricity: 4. 2 NaCl  2 Na + Cl 2 metal carbonates decompose to form metal oxides and carbon dioxide. 5. Al 2 (CO 3 ) 3  Al 2 O CO 2 metal hydroxides decompose to form metal oxides and water. 6. Mg(OH) 2  MgO + H 2 O

Decomposition AX  A + X 2MgO  2Mg + O 2 O Mg O

CuO  Fe 2 O 3  MnO 2  PbO  Cu + O 2 Fe + O 2 Mn + O 2 Pb + O Practice decomposing oxides:

Decomposition of metal carbonates ACO 3  AO + CO 2 (g) SrCO 3 (s)  SrO (s) + CO 2 (g) O Sr O This reaction occurs when you heat strontium carbonate. strontium oxide and carbon dioxide form. O C

CuCO 3  Na 2 CO 3  MgCO 3  Ag 2 CO 3  CuO + CO 2 Na 2 O + CO 2 MgO + CO 2 Ag 2 O + CO 2 Practice decomposing carbonates:

Decomposition of metal hydroxides AOH  AO + H 2 O (g) Ca(OH) 2 (s)  CaO (s) + H 2 O (g) H Ca O This reaction occurs when you heat calcium hydroxide. calcium oxide and water form. O H

NaOH  Al(OH) 3  Cu(OH) 2  Mg(OH) 2  Na 2 O + H 2 O Al 2 O 3 + H 2 O CuO + H 2 O MgO + H 2 O Practice decomposing hydroxides:

Decomposition of metal chlorates AClO 3  ACl + O 2 (g) 2KClO 3 (s)  2KCl (s) + 3O 2 (g) K O This reaction occurs when you heat potassium chlorate. potassium chloride and oxygen form. Cl O K O O O O

HClO 3  NaClO 3  Cu(ClO 3 ) 2  HCl + O 2 NaCl + O 2 CuCl 2 + O Practice decomposing chlorates:

Decomposition of acids H 2 CO 3 (aq)  H 2 O (l) + CO 2 (g) Carbonic acid in pop decomposes when warmed. water and carbon dioxide form. O O O C H H

Combined Practice: 2 Ag 2 O  2 CuClO 3  Na 2 CO 3  Ca(OH) 2  4 Ag + O 2 2 CuCl O 2 Na 2 O + CO 2 CaO + H 2 O