2.  I can identify elements vs. compounds in a chemical equation  I can name the 7 diatomic elements  I can identify precipitation vs. redox reactions

3.  Compounds are combinations of elements that are chemically combined.  examples: H 2 O 2 CO 2 H 2 O C 4 H 8 Fe 2 O 3  When not in a compound, most elements exist as single atoms but seven elements exist as diatomic molecules  There are 7 diatomic elements  H 2, O 2, F 2, Br 2, I 2, N 2, Cl 2

4.  there are 7 diatomic elements

5.  Every minute of the day chemical reactions take place.  In your body, complex chemical reactions digest food.  Plants use sunlight to drive the photosynthesis reaction.  A chemical reaction produces electrical energy in your car battery  An undesirable chemical reaction with oxygen occurs with your car fender to produce rust.

6.  Describing chemical reactions using balanced chemical equations is an essential skill.  reactants → products  Symbols you might see in a balanced chemical equation:  (s)solid  (l)liquid  (g)gas  (aq)aqueous – dissolved in water   ( above the arrow) indicates the reactants are heated

7.  When solid sodium hydrogen carbonate is heated, it decomposes, forming the products solid sodium carbonate, carbon dioxide gas and water vapor.  Write the Chemical Equation:

8.  Chemical reactions can be categorized into two types;  Precipitation reactions.  Oxidation – Reduction reactions called redox  In a precipitation reaction, cations and anions in aqueous solution are rearranged to form a solid product called a precipitate.  In an oxidation – reduction reaction (or redox reaction), electrons are lost by one element and gained by another element.

9.  Precipitate Reaction examples: AgNO 3 (aq) + NaCl(aq) → AgCl(s) + NaNO 3 (aq) Na 2 S(aq) + Cd(NO 3 ) 2 (aq) → CdS(s) + 2NaNO 3 (aq) BaCl 2 (aq) + K 2 CO 3 (aq) → BaCO 3 (s) + 2KCl(aq) Pb(ClO 4 ) 2 (aq) + 2NaI(aq) → PbI 2 (s) + 2NaClO 4 (aq)  What do these reactions have in common?

10.  Redox reaction examples: 2K(s) + Cl 2 (g) → 2KCl(s) 2H 2 O 2 (aq) → 2H 2 O(l) + O 2 (g) 2Al(s) + 3Cu(SO 4 )(aq) → 3Cu(s) + Al 2 (SO 4 ) 3 (aq) Pb(s) + 2 AgNO 3 (aq) → 2 Ag(s) + Pb(NO 3 ) 2 (aq) CH 4 (g) + O 2 (g) → CO 2 (g) + 2 H 2 O(l)  What do these reactions have in common?

11. PRECIPITATION REACTIONS REDOX (OXIDATION-REDUCTION) REACTIONS  reactants cations & anions are rearranged  aqueous solutions react to form a precipitate  (aq) + (aq)  (s) + (aq)  a precipitate is a solid formed in a solution  reactants & products are ionic compounds – NOT elements  electrons are lost by one element and gained by another element  typically a reactant or product or both is an element  elements can be diatomic molecules  H 2, O 2, N 2, F 2, Br 2, I 2, Cl 2

12. A. precipitaiton B. redox

13. A. precipitaiton B. redox

14. A. precipitaiton B. redox

15. A. precipitaiton B. redox

16. A. precipitaiton B. redox

17. A. precipitation B. redox

18. A. precipitation B. redox

19.  I can identify elements vs. compounds in a chemical equation  I can name the 7 diatomic elements  I can identify precipitation vs. redox reactions