Types of Chemical Reactions ,

Targets TLW covert word equations to symbolic, vice versa. TLW Identify the reactants, products, and types of different chemical reactions: composition, decomposition, double replacement, single replacement, combustion.

Polyatomic Ions Most polyatomic ions are negatively charged!! Notice you have 2 polyatomic ions with a positive charge: NH 4 1+ H 3 O 1+

Acids, Bases, and Salts As a rule, acids contain an H atom in a compound that can be lost to form an H + ion. OH - (hydroxide) is basic. Salts usually form between a metal and a halogen (recall that halogens are known as salt-formers)

Common Acids Hydrobromic acid HBr Hydrochloric acid HCl Hydrosulfuric acid H 2 S Hydrofluoric acid HF

Naming Acids Binary Acids -contain hydrogen and one other element -hydroelementic acid H 2 S hydrosulfuric acid HBr hydrobromic acid Tertiary Acids (Oxyacids)  found in Chem. Cruncher -named after element other than oxygen and hydrogen (*notice polyatomic ions) H 2 SO 4 sulfuric acidH 2 SO 3 sulfurous acid HClO 3 chloric acidHClO 2 chlorous acid HClO hypochlorous acid

Identifying acids and bases from other compounds HCl (aq) hydrochloric acidHCl (s) hydrogen chloride HBr (aq) hydrobromic acid HBr (s) hydrogen bromide HF (aq) hydrofluoric acidHF (s) hydrogen fluoride (aq) dissolved in water (s) solid (l) liquid (g) or ↑ gas ∆heat has been added ↔reversible reaction

aqueous sodium chloride reacts with aqueous lead (II) nitrate to yield a lead (II) chloride precipitate and aqueous sodium nitrate

aqueous barium nitrate reacts with sulfuric acid [H 2 SO 4 (aq)] to yield a barium sulfate precipitate and nitric acid [HNO 3 (aq)]

silver nitrate reacts in solution with potassium chromate to yield a silver chromate precipitate and soluble potassium nitrate

solid calcium carbonate reacts with hydrochloric acid [HCl(aq)] to yield aqueous calcium chloride, carbon dioxide gas, and liquid water

aqueous zinc chloride reacts with dihydrogen monosulfide gas to yield a zinc sulfide precipitate and hydrochloric acid

Combustion Chemical reaction in which oxygen (O 2 ) reacts with another element forming carbon dioxide (CO 2 ) and water (H 2 O) C 10 H O 2  10 CO H 2 O

Synthesis A chemical reaction in which two or more simple compounds combine to form a more complicated one A + B  AB 8 Fe + S 8 ---> 8 FeS

Decomposition Chemical reaction in which a complicated compound breaks down into two or more simpler compounds XY  X + Y 2 H 2 O ---> 2 H 2 + O 2

Single Displacement Chemical reaction in which one element trades places with another element in a compound A + XY  AY + X Mg + 2 H 2 O ---> Mg(OH) 2 + H 2

Double Displacement A chemical reaction in which the anions and cations of two different molecules switch places, forming two entirely different compounds AB + XY  AY + XB Pb(NO 3 ) KI ---> PbI KNO 3

Acid-Base Special kind of double displacement reaction that takes place when an acid and base react with other. The H + ion in the acid reacts with the OH - ion in the base, resulting in the formation of water. HA + BOH  H 2 O + AB HBr + NaOH ---> NaBr + H 2 O

Guch’s Handy Checklist: Follow this series of questions. When you can answer “yes,” STOP!!! 1) Does your reaction have oxygen as one of it's reactants and carbon dioxide and water as products? If yes, then it's a combustion reaction 2) Does your reaction have two (or more) chemicals combining to form one chemical? If yes, then it's a synthesis reaction 3) Does your reaction have one large molecule falling apart to make several small ones? If yes, then it's a decomposition reaction 4) Does your reaction have any molecules that contain only one element? If yes, then it's a single displacement reaction 5) Does your reaction have water as one of the products? If yes, then it's an acid-base reaction 6) If you haven't answered "yes" to any of the questions above, then you've got a double displacement reaction

Practice 1) NaOH + KNO 3 --> NaNO 3 + KOH 2) CH O 2 --> CO H 2 O 3) 2 Fe + 6 NaBr --> 2 FeBr Na 4) CaSO 4 + Mg(OH) 2 --> Ca(OH) 2 + MgSO 4 5) NH 4 OH + HBr --> H 2 O + NH 4 Br 6) Pb + O 2 --> PbO 2 7) Na 2 CO 3 --> Na 2 O + CO 2