1. Chemical Reactions Chapter 10

2. Chemical reaction =process by which the atoms of one or more substances rearrange to form different substances.

3. Law of Conservation of Matter: Matter is not created or destroyed in a Chemical Reaction

4. Evidence of a chemical reaction 1)Release of energy in the form of heat or light (exothermic reaction) 2) Absorption of energy (endothermic reaction)

5. Evidence of a chemical reaction 3) Color change

6. Evidence of a chemical reaction 4) Appearance of a solid 5) Appearance of bubbles 6) Odor

7. Chemical Equations 1)Reactants  Products 2)Symbols: (s) solid state (l)liquid state (g)gaseous state (aq) aqueous = water solution Example:

8. Word equations Liquid carbon disulfide reacts with oxygen gas, producing carbon dioxide gas and sulfur dioxide gas Solid zinc and aqueous hydrogen sulfate react to produce hydrogen gas and aqueous zinc sulfate

9. Skeleton equations Iron (s) + chlorine (g)  iron III chloride (s) Carbon (s) + sulfur (s)  carbon disulfide (l)

10. Reading a chemical equation

11. Reading a chemical equation with Coefficients

12. Balancing a chemical equation: 1) Write the skeleton equation for a reaction. 2) Change the coefficients until the number of atoms of each element are equal on both sides of the equation. 3) Make sure the coefficients are in their lowest ratio.

13. Balance the equation ___ C (s) + ___ S (s)  ___ CS 2 (l) ___ Fe (s) + ___Cl 2 (g)  ___ FeCl 3 (s)

14. Balance the equation __ CH 4 (g) +__ O 2 (g)  __CO 2 (g) +__H 2 O(g) __C 2 H 6 (g) +__ O 2 (g)  __CO 2 (g) +__H 2 O(g)

15. Balance the equation __K 2 CrO 4 (aq) + ___Pb(NO 3 ) 2 (aq)  ___KNO 3 (aq) + ___PbCrO 4 (s) ___Fe (s) + ___Sn(NO 3 ) 4 (aq)  ___Fe(NO 3 ) 3 (aq) + ___ Sn (s)