1. Reaction Types Chapter 10

2. Objectives: Identify the reactants and products in a chemical equation Identify the reactants and products in a chemical equation From the word equation for a chemical reaction, write and balance the formula equation for the reaction From the word equation for a chemical reaction, write and balance the formula equation for the reaction Identify a chemical reaction as one of the five major reaction types Identify a chemical reaction as one of the five major reaction types

3. Reaction Types There are 5 basic reaction types: There are 5 basic reaction types: –Synthesis –Decomposition –Single Replacement –Double Replacement –Organic Combustion

4. Synthesis In a synthesis reaction, one compound forms from 2 or more simpler reactants In a synthesis reaction, one compound forms from 2 or more simpler reactants i.e. A + B  AB i.e. A + B  AB The reactants can be either elements or compounds The reactants can be either elements or compounds E.g. C 2 H 4 (g) + H 2 O(g)  C 2 H 5 OH(g) E.g. C 2 H 4 (g) + H 2 O(g)  C 2 H 5 OH(g) –{Is this balanced?} E.g. H 2 (g) + O 2 (g)  H 2 O(l) E.g. H 2 (g) + O 2 (g)  H 2 O(l) –{Is this balanced?}

5. Decomposition In a decomposition reaction, a compound breaks down into 2 or more simpler products In a decomposition reaction, a compound breaks down into 2 or more simpler products i.e. AB  A + B i.e. AB  A + B An external energy source is usually required for these reactions to occur An external energy source is usually required for these reactions to occur –E.g. heat, light, electricity A ternary acid will decompose to yield water and a nonmetallic oxide. A ternary acid will decompose to yield water and a nonmetallic oxide. –E.g. H 2 C0 3  CO 2 + H 2 0 {Is this balanced?} Ammonium carbonate decomposes into ammonia, carbon dioxide, and water Ammonium carbonate decomposes into ammonia, carbon dioxide, and water –i.e. (NH 4 ) 2 CO 3  NH 3 + CO 2 + H 2 0 {Is this balanced?}

6. Additional Decomposition Examples E.g. CaCO 3 (s)  CaO(s) + CO 2 (g) E.g. CaCO 3 (s)  CaO(s) + CO 2 (g) –{Is this balanced?} E.g. NH 4 NO 3 (s)  N 2 (g) + H 2 O(g) + O 2 (g) E.g. NH 4 NO 3 (s)  N 2 (g) + H 2 O(g) + O 2 (g) –{Is this balanced?} E.g. H 2 O(l)  H 2 (g) + O 2 (g) E.g. H 2 O(l)  H 2 (g) + O 2 (g) –{Is this balanced?}

7. Single Displacement In a Single Displacement reaction, one partner switches in an aqueous solution In a Single Displacement reaction, one partner switches in an aqueous solution i.e. AX + B  A + BX i.e. AX + B  A + BX

8. Single Displacement with Metals The replacing metal (B) can only switch if it is more active than the original metal (A). The replacing metal (B) can only switch if it is more active than the original metal (A). –E.g. Cu + AgNO 3  Cu(NO 3 ) 2 + Ag Metals which are more active than hydrogen will replace hydrogen from acids to form a salt and hydrogen gas. Metals which are more active than hydrogen will replace hydrogen from acids to form a salt and hydrogen gas. –E.g. HCl + Mg  MgCl 2 + H 2 {Is this balanced?} Very active metals react with water to form a base and hydrogen gas. Very active metals react with water to form a base and hydrogen gas. –E.g. Na + H 2 O  NaOH + H 2 {Is this balanced?} AX + B  A + BX

9. Single Displacement with Nonmetals Nonmetals will take the place of the ion in the compound which has a negative charge Nonmetals will take the place of the ion in the compound which has a negative charge The nonmetal must be more active than the nonmetal which it replaces. The nonmetal must be more active than the nonmetal which it replaces. E.g. Na + H 2 O  NaOH + H 2 E.g. Na + H 2 O  NaOH + H 2 –{Is this balanced?} AX + B  A + BX

10. Single Displacement (Cont) To predict the products: To predict the products: –Separate the reactants into their respective ions –Move the anion to the other cation to form Product 1 –Determine whether Product 2 (the leftover cation) is monatomic or diatomic –Balance the resulting equation E.g. Zn(s) + HCl(aq)  ZnCl 2 (aq) + H 2 (g) E.g. Zn(s) + HCl(aq)  ZnCl 2 (aq) + H 2 (g) –{Is this balanced?} E.g. Zn(s) + CuCl 2 (aq)  ZnCl 2 (aq) + Cu(s) E.g. Zn(s) + CuCl 2 (aq)  ZnCl 2 (aq) + Cu(s) –{Is this balanced?} AX + B  A + BX

11. Double Displacement In a Double Displacement reaction, two aqueous solutions react to form a precipitate and an aqueous solution. Both partners switch. In a Double Displacement reaction, two aqueous solutions react to form a precipitate and an aqueous solution. Both partners switch. i.e. AX(aq) + BY(aq)  AY(s) + BX(aq) i.e. AX(aq) + BY(aq)  AY(s) + BX(aq) –{AY would be the precipitate in this case}

12. Double Displacement: Predicting the Products Separate the reactants into their respective ions Separate the reactants into their respective ions Put the anion of Reactant 2 with the cation of Reactant 1 to form Product 1 Put the anion of Reactant 2 with the cation of Reactant 1 to form Product 1 Put the anion of Reactant 1 with the cation of Reactant 2 to form Product 2 Put the anion of Reactant 1 with the cation of Reactant 2 to form Product 2 Determine which product will form the precipitate and label it (s) Determine which product will form the precipitate and label it (s) Balance the resulting equation Balance the resulting equation

13. Double Displacement Examples E.g. BaCl 2 (aq) + Na 2 SO 4 (aq)  BaSO 4 (s) + NaCl(aq) E.g. BaCl 2 (aq) + Na 2 SO 4 (aq)  BaSO 4 (s) + NaCl(aq) –{Is this balanced?} E.g. AgNO 3 (aq) + NaCl(aq)  AgCl(s) + NaNO 3 (aq) E.g. AgNO 3 (aq) + NaCl(aq)  AgCl(s) + NaNO 3 (aq) –{Is this balanced?}

14. Organic Combustion In an organic combustion reaction, an organic compound, usually a carbohydrate, reacts with oxygen to form carbon dioxide, water vapor, heat, and light. In an organic combustion reaction, an organic compound, usually a carbohydrate, reacts with oxygen to form carbon dioxide, water vapor, heat, and light. i.e. C x H y O z + O 2  CO 2 + H 2 O + Heat + Light i.e. C x H y O z + O 2  CO 2 + H 2 O + Heat + Light E.g. CH 4 + O 2  CO 2 + H 2 O E.g. CH 4 + O 2  CO 2 + H 2 O –{Is this balanced?} E.g. C 2 H 6 + O 2  CO 2 + H 2 O E.g. C 2 H 6 + O 2  CO 2 + H 2 O –{Is this balanced?}

15. Homework! Study balancing equations tonight and do the reaction types homework. Study balancing equations tonight and do the reaction types homework. Balancing Equations Quiz tomorrow, discuss reaction types homework, begin predicting the products lecture Balancing Equations Quiz tomorrow, discuss reaction types homework, begin predicting the products lecture