1. ring stand round bottom flask iron ring pre-1982 penny clamp rubber stopper tubing graduated cylinder

2. 2 Equation for the reaction: Cu(s) + HNO 3 (aq)  NO 2 (g) + H 2 O(l) + Cu(NO 3 ) 2 (aq) reactants  products Copper + nitric acid produces nitrogen + water + copper(II)nitrate dioxide things on the left  things on the right

3. 3 State symbols “s” = solid “l” = liquid “g” = gas “aq” = aqueous (dissolved in water)

4. 4 Energy changes Because heat is released in this reaction it is called an “exothermic” reaction.

5. 5 Why does the penny have to be “old”? Pre-1982 pennies are mostly copper. Post-1982 pennies are made up of a zinc core surrounded by a thin layer of copper.

6. 6 Chemistry of Color The NO 2 gas produced is brown—ALL COLORED GASES ARE POISONOUS. Copper ions tend to produce blue solutions.