C. Johannesson Ch. 10 – Chemical Reactions III. Types of Chemical Reactions

C. Johannesson A. Combustion CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O(g) the burning of any substance in O 2 to produce heat A + O 2  B

C. Johannesson Na(s)+ O 2 (g)  C 3 H 8 (g)+ O 2 (g)  A. Combustion Products: –contain oxygen in reactants –hydrocarbons form CO 2 + H 2 O CO 2 (g)+ H 2 O(g) Na 2 O(s) 4 2

C. Johannesson B. Synthesis the combination of 2 or more substances to form a compound only one product A + B  AB

C. Johannesson B. Synthesis H 2 (g) + Cl 2 (g)  2 HCl(g)

C. Johannesson Al(s)+ Cl 2 (g)  AlCl 3 (s) B. Synthesis Products: –ionic - cancel charges –covalent - hard to tell

C. Johannesson C. Decomposition a compound breaks down into 2 or more simpler substances only one reactant AB  A + B

C. Johannesson C. Decomposition 2 H 2 O(l)  2 H 2 (g) + O 2 (g)

C. Johannesson KBr(l)  K(s) + Br 2 (l) 2 2 C. Decomposition Products: –binary - break into elements –others - hard to tell (look at reference table)

C. Johannesson D. Single Replacement one element replaces another in a compound –metal replaces metal (+) –nonmetal replaces nonmetal (-) A + BC  B + AC

C. Johannesson D. Single Replacement Cu(s) + 2AgNO 3 (aq)  Cu(NO 3 ) 2 (aq) + 2Ag(s)

C. Johannesson Fe(s)+ CuSO 4 (aq)  Cu(s)+ FeSO 4 (aq) D. Single Replacement Products: –metal  metal (+) –nonmetal  nonmetal (-) –free element must be more active (check activity series) Br 2 (l)+ NaCl(aq)  N.R.

C. Johannesson

AB + CD  AD + CB E. Double Replacement ions in two compounds “change partners” cation of one compound combines with anion of the other

C. Johannesson E. Double Replacement Products: –switch negative ions –one product must be insoluble (check solubility table)

C. Johannesson E. Double Replacement Pb(NO 3 ) 2 (aq) + K 2 CrO 4 (aq)  PbCrO 4 (s) + 2KNO 3 (aq)

C. Johannesson Writing Net Ionic Equations for Double Replacement Reactions A net ionic equation only shows the ions that were used to make the precipitate. Some ions were always dissolved in water. These are called “spectator ions”. (They don’t do anything, so we can ignore them.) Example: CaCl 2 (aq) + 2AgNO 3 (aq)  Ca(NO 3 ) 2 (aq) + 2AgCl (s) Ionic Equation Written as Ions Dissolved in Water: ___ (aq) + ___ (aq) + ___ (aq) + _____ (aq)  ___ (aq) + _____ (aq) + _________ (s) Cancel out the spectator ions, and you are left with the Net Ionic Equation! ________ + _________  __________ Ca +2 2Cl − 2Ag + 2NO 3 − Ca +2 2NO 3 − 2AgCl 2Cl − (aq) 2Ag + (aq) 2AgCl (s)

C. Johannesson Writing Net Ionic Equations for Double Replacement Reactions Practice Problem: Write the net ionic equation for the following reaction. K 2 CO 3 (aq) + Ba(NO 3 ) 2 (aq)  _________ + _________ Net Ionic Equation = _________________________  ___________ KNO 3 BaCO 3(aq) CO 3 −2 (aq) Ba +2 (aq) +BaCO 3

C. Johannesson In Summary… To write the complete and net ionic equations… 1.Write formulas* of reactants and use solubility rules to determine state (aq or s) 2.Determine the products (switch the negative ions) -write formulas* and use solubility rules to determine state (aq or s) * don’t forget to use the periodic table and list of polyatomic ions to determine charge

C. Johannesson 3. Balance equation (this is a balanced chemical equation) 4. Split anything that is aq into ions -leave the s alone (this is the complete ionic equation) 5. Cross out spectator ions 6. Write what is left (this is the net ionic equation)

C. Johannesson Activity Series (Single Replacement reactions) Higher up = more reactive Elements from Li to Na can displace hydrogen in water to form a metallic hydroxide and H 2 gas.

C. Johannesson Single Replacement Reactions Examples: NaCl + F 2  _____ + _____ FeCl 2 + K  _____ + _____ HCl + Zn  _____ + _____ HCl + Au  _____ + _____ H 2 O + Na  _____ + _____ H 2 O + Fe  _____ + _____ AgNO 3 + Cu  _____ + _____ NaFCl 2 KClFe ZnCl 2 H2H2 no reaction NaOH H2H2 CuNO 3 Ag H(OH) no reaction