11.1 Describing Chemical Reactions

Chemical Reactions?!

Word Equations Reactant(s)  Product(s) Arrow is read as yields, gives, or reacts to produce Example: iron + oxygen  iron (III) oxide

Chemical Equations Write the formulas of the reactants to the left of the arrow, products to the right. Example: Fe(s) + O2(g)  Fe2O3(s) (s) = solid, (l) = liquid (g) = gas, (aq) = aqueous Catalyst = speeds up rxn. (written above the arrow)

Balancing Chemical Equations Shows how much of each reactant you need and product you will get. Coefficients = #s in front of formulas ***both sides of the equation need to have the same # of each atom of each element (Law of Conservation of Mass) C(s) + O2(g)  CO2(g)

Balance THIS H2(g) + O2(g)  H2O(l) 2H2(g) + O2(g)  2H2O(l) AgNO3 + H2S  Ag2S + HNO3 2AgNO3 + H2S  Ag2S + 2HNO3 Trouble? See page 327 for a list of rules to follow

Note… Need smallest whole-number ratio Example: 8Al + 6O2  4Al2O3 Simplify: 4Al + 3O2  2Al2O3

HINTS… ALWAYS do oxygen LAST Watch out: H2O = HOH