Bell work What are the products when an acid and a base react together? Test on Friday over chapter 11

Cathode and anode What are they? Describe them in your own words During the electrolysis of water, which atom is the cathode and which is the anode?

Reactions with elements Some active metals are able to react with water at room temperature We could say that most of these reactions are single replacement reactions –Example: the reaction of water and sodium –2Na + 2H 2 O = 2 NaOH + H 2 –Sodium and hydroxide separate and remain in the water while hydrogen gas is released

Anhydrides Compounds that react with water in composition reactions Two are to be considered: metal oxides and nonmetal oxides Oxides: very active metals: sodium, potassium, barium, and calcium

More on Anhydrides Basic anhydrides: a metal oxide that forms a base when added to water Example: Na 2 O + H 2 O = 2NaOH (base) Acidic anhyrides: when a nonmetal oxide forms an acid when added to water Example: CO 2 + H 2 O = H 2 CO 3 (acid)

Work on the following questions Section review pg Chapter review pg in your notes Homework (due tomorrow) if not finished today

Bell work What is electrolysis HW: due Thursday: section review pg and chapter review pg Make sure to have the review sheet for chapter 11 finished as well on Thursday for review

Summarize pgs After your summary work on pg And work on chapter review pg When finished work on your review sheet for chapter 11 test

Water in compounds We can find water almost everywhere Hydrates: chemical compounds that include water in their crystal structures Water molecules occupy the crystals empty space in some crystals Many hydrates are salts

Compounds and water When water is incorporated into the crystal it is called water of hydration Example: CuSO4 and 5 H2O Called: copper (II) sulfate pentahydrate Water molecules can be taken out of crystals by heat CuSO4 and 5 H2O = CuSO4 + 5 H2O

Hydroscopic compounds Hydroscopic: compounds that absorb water from the air Sodium hydroxide is one of these compounds; it pulls in water when left out On a balance we would see the increase on the balance as sodium hydroxide pulls the water molecules in

Desiccators Desiccators: are sealable enclosures containing desiccants used for preserving moisture-sensitive items A common use for desiccators are to protect hygroscopic chemicals such as rubidium chloride from humidity