The document discusses chemical reactions and how to write chemical equations. It explains that chemical reactions involve rearranging bonds and atoms to form new compounds that are different than the starting materials. It provides examples of word and formula equations and shows the parts of a chemical equation including reactants, products, and physical states. It also instructs how to write chemical equations by converting word equations to symbolic equations using chemical formulas and reaction arrows.

1. Section 2.6—Chemical Reactions If we’re going to do chemical reactions with antacids, we’d better know how to write them!

2. Chemical Reactions Watch as 2 H 2 and 1 O 2 undergo a chemical reaction Bonds and atoms are rearranged to form new compounds. 2 H 2 + O 2  2 H 2 O O O H H H H

3. Chemical Reactions Bonds and atoms are rearranged to form new compounds. The compounds in the end are different from those in the beginning Bonds are broken and formed between different atoms 2 H 2 + O 2  2 H 2 O O O H H O H H O H H H H

4. Chemical Equations The “sentence” of chemistry that shows how the starting materials and the final products of a chemical reaction

5. Examples of Chemical Equations Word equation: magnesium metal is reacted with aqueous hydrochloric acid to produce aqueous magnesium chloride and hydrogen gas Visualization Formula equation: Mg (s) + 2 HCl (aq) MgCl 2 (aq) + H 2 (g)

6. Parts of a Chemical Equation NaCl (aq) + AgNO 3 (aq)  AgCl(s) + NaNO 3 (aq) Reactants States of matter Arrow Products The starting materials for the reaction—each compound is separated by a “+” s = solid l = liquid g = gas aq = aqueous (dissolved in water) Read as: Yields Produces Forms Makes etc. Formed in the reaction

7. Writing Chemical Equations You must write each chemical formula correctly first! (Section 2.2) “ and”, “is mixed with” or “reacts with” = + “ yield”, “produces” and “forms” =  We will learn to balance equations in the next section, so don’t worry about it now!

8. Let’s Practice #1 Example: Write the word equation into symbol form Aluminum metal is reacted with hydrochloric acid to form aluminum chloride and hydrogen gas

9. Let’s Practice #1 Aluminum metal is reacted with hydrochloric acid to form aluminum chloride and hydrogen gas Al + HCl  AlCl 3 + H 2 Example: Write the word equation into symbol form

10. Let’s Practice #2 Example: Write the word equation into symbol form Copper (II) nitrate and sodium hydroxide form copper (II) hydroxide and sodium nitrate

11. Let’s Practice #2 Copper (II) nitrate and sodium hydroxide form copper (II) hydroxide and sodium nitrate Cu(NO 3 ) 2 + NaOH  Cu(OH) 2 + NaNO 3 Example: Write the word equation into symbol form