Section 2-6: Chemical Reactions

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


Chemical Reactions :Watch as 2 H2 and 1 O2 undergo a chemical reaction Bonds and atoms are rearranged to form new compounds. 2 H2 + O2  2 H2O Chemical Reactions


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 H2 + O2  2 H2O Chemical Reactions


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


Examples of Chemical Equations :Examples of Chemical Equations Word equation: magnesium metal is reacted with aqueous hydrochloric acid to produce aqueous magnesium chloride and hydrogen gas Visualization


Parts of a Chemical Equation :Parts of a Chemical Equation NaCl (aq) + AgNO3 (aq)  AgCl(s) + NaNO3 (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


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” =  Writing Chemical Equations We will learn to balance equations in the next section, so don’t worry about it now!


Let’s Practice #1 :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


Let’s Practice #1 :Aluminum metal is reacted with hydrochloric acid to form aluminum chloride and hydrogen gas Let’s Practice #1 Al + HCl  AlCl3 + H2 Example: Write the word equation into symbol form


Let’s Practice #2 :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


Let’s Practice #2 :Copper (II) nitrate and sodium hydroxide form copper (II) hydroxide and sodium nitrate Let’s Practice #2 Cu(NO3)2 + NaOH  Cu(OH)2 + NaNO3 Example: Write the word equation into symbol form


Double Replacement Reactions :NaCl + AgNO3  AgCl + NaNO3 Double Replacement Reactions The cations from two compounds replace each other. Two ionic compounds switch ions


Double Replacement Reactions :Double Replacement Reactions General format of a double replacement reaction:


Neutralization Reactions :Neutralization Reactions General format of a neutralization reaction: Neutralization reactions are double replacement reactions where one cation is “H” and one anion is “OH” and water is formed