Types of Chemical Reactions

Review A chemical equation describes a chemical change. A chemical equation describes a chemical change. The Law of Conservation of Mass says that the number and kind of atoms going INTO a chem. rxn must be the same as the number and kind of atoms coming OUT. The Law of Conservation of Mass says that the number and kind of atoms going INTO a chem. rxn must be the same as the number and kind of atoms coming OUT. Balancing an equation makes it obey the Law of Conservation of Mass. Balancing an equation makes it obey the Law of Conservation of Mass.

Types of Reactions Chem. rxns are often separated into different categories. Chem. rxns are often separated into different categories.

Types of Chemical Reactions The five types of chemical reactions we will discuss are: The five types of chemical reactions we will discuss are: Synthesis Synthesis Decomposition Decomposition Single Displacement Single Displacement Double Displacement Double Displacement Combustion Combustion

Synthesis Reactions Two or more substances combine to form one substance. Two or more substances combine to form one substance. The general form is A + X  AX The general form is A + X  AX Example: Example: 2Mg + O 2  2MgO 2Mg + O 2  2MgO

Decomposition Reactions One substance reacts to form two or more substances. One substance reacts to form two or more substances. The general form is AX  A + X The general form is AX  A + X Example: Example: 2H 2 O  2H 2 + O 2 2H 2 O  2H 2 + O 2

Single Displacement Reactions A metal replaces a metal ion (or H + ) in a cmpd. A metal replaces a metal ion (or H + ) in a cmpd. The general form is A + BX  AX + B The general form is A + BX  AX + B A nonmetal replaces a nonmetal ion in a cmpd. A nonmetal replaces a nonmetal ion in a cmpd. The general form is Y + BX  BY + X The general form is Y + BX  BY + X

Single Displacement Reactions

Examples: Examples: Ni + AgNO 3  Ni + AgNO 3  Nickel replaces the metallic ion Ag +. Nickel replaces the metallic ion Ag +. The silver becomes free silver and the nickel becomes the nickel(II) ion. The silver becomes free silver and the nickel becomes the nickel(II) ion. Ni + 2AgNO 3  2Ag + Ni(NO 3 ) 2 Ni + 2AgNO 3  2Ag + Ni(NO 3 ) 2

Double Displacement Reactions Ions of two compounds exchange places with each other. Ions of two compounds exchange places with each other. The general form is: The general form is: AX + BY  AY + BX AX + BY  AY + BX

Double Displacement NaOH + CuSO 4  NaOH + CuSO 4  The Na + and Cu 2+ switch places. The Na + and Cu 2+ switch places. Na + combines with SO 4 2- to form Na 2 SO 4. Na + combines with SO 4 2- to form Na 2 SO 4. Cu 2+ combines with OH - to form Cu(OH) 2 Cu 2+ combines with OH - to form Cu(OH) 2 2NaOH + CuSO 4  Na 2 SO 4 + Cu(OH) 2 2NaOH + CuSO 4  Na 2 SO 4 + Cu(OH) 2

Combustion Reaction When a substance combines with oxygen, a combustion reaction results. When a substance combines with oxygen, a combustion reaction results. Combustion Reaction: A fuel reacts with oxygen to produce oxides of the fuel’s elements. Combustion Reaction: A fuel reacts with oxygen to produce oxides of the fuel’s elements. The combustion reaction may be burning of a fuel. The combustion reaction may be burning of a fuel.

Combustion Reaction When hydrocarbon compounds are burned in oxygen, the products are water and carbon dioxide. When hydrocarbon compounds are burned in oxygen, the products are water and carbon dioxide. CH 4 + 2O 2  CO 2 + 2H 2 O CH 4 + 2O 2  CO 2 + 2H 2 O

Combustion Reactions Combustion reactions release light and heat. Combustion reactions release light and heat. Natural gas, propane, gasoline, etc. are burned to produce heat energy. Natural gas, propane, gasoline, etc. are burned to produce heat energy. Most of these organic reactions produce water and carbon dioxide. Most of these organic reactions produce water and carbon dioxide. If any elements are present in the fuel besides C and H, the reaction will also produce oxides of those elements. If any elements are present in the fuel besides C and H, the reaction will also produce oxides of those elements.

Practice Classify each of the following reactions: Classify each of the following reactions: H 2 + Cl 2  2HCl H 2 + Cl 2  2HCl Synthesis Synthesis Ca + 2H 2 O  Ca(OH) 2 + H 2 Ca + 2H 2 O  Ca(OH) 2 + H 2 Single displacement Single displacement

Practice 2CO + O 2  2CO 2 2CO + O 2  2CO 2 Synthesis Synthesis 2KClO 3  2KCl + 3O 2 2KClO 3  2KCl + 3O 2 Decomposition Decomposition

Practice CH 3 SH + 3O 2  CO 2 + 2H 2 O + SO 2 CH 3 SH + 3O 2  CO 2 + 2H 2 O + SO 2 Combustion Combustion Zn + 2HCl  ZnCl 2 + H 2 Zn + 2HCl  ZnCl 2 + H 2 Single replacement Single replacement

Predicting the Outcomes of Chemical Reactions Predicting Single Displacement Outcomes Predicting Single Displacement Outcomes Need activity series handout. Need activity series handout. Any metal on the activity series is capable of displacing any metal ion below it. Any metal on the activity series is capable of displacing any metal ion below it. Metals cannot displace more active metals. Metals cannot displace more active metals. If a metal is placed in contact with a compound that has a more active metal, no reaction will occur. If a metal is placed in contact with a compound that has a more active metal, no reaction will occur. A halogen can displace any halogen beneath it. A halogen can displace any halogen beneath it. Example: Cl 2 can displace Br -1 ions and I -1 ions from compounds, but it cannot displace F -1 ions. Example: Cl 2 can displace Br -1 ions and I -1 ions from compounds, but it cannot displace F -1 ions.

Predicting the Outcomes of Chemical Reactions Predict whether a chem. rxn will occur in each of the following cases, and if it does, what products it will form. Predict whether a chem. rxn will occur in each of the following cases, and if it does, what products it will form. Mg + Cu(NO 3 ) 2  ??? Mg + Cu(NO 3 ) 2  ??? Mg is higher than Cu on the activity series. Mg is higher than Cu on the activity series. Mg will displace Cu from Cu(NO 3 ) 2. Mg will displace Cu from Cu(NO 3 ) 2. The expected products are Mg(NO 3 ) 2 and Cu. The expected products are Mg(NO 3 ) 2 and Cu. Mg + Cu(NO 3 ) 2  Mg(NO 3 ) 2 + Cu Mg + Cu(NO 3 ) 2  Mg(NO 3 ) 2 + Cu Fe + AlCl 3  ??? Fe + AlCl 3  ??? Fe is lower than Al on the activity series. Fe is lower than Al on the activity series. There will be no chemical reaction. There will be no chemical reaction.

Predicting the Outcomes of Chemical Reactions Would you expect each of the following chemical reactions to occur as written? Would you expect each of the following chemical reactions to occur as written? Li + NaCl  LiCl + Na Li + NaCl  LiCl + Na 2Al + 3CuCl 2  2AlCl 3 + 3Cu 2Al + 3CuCl 2  2AlCl 3 + 3Cu Ni + Zn(NO 3 ) 2  Ni(NO 3 ) 2 + Zn Ni + Zn(NO 3 ) 2  Ni(NO 3 ) 2 + Zn Mg + 2HBr  MgBr 2 + H 2 Mg + 2HBr  MgBr 2 + H 2 F 2 + 2KBr  2KF + Br 2 F 2 + 2KBr  2KF + Br 2 I 2 + 2KBr  2KI + Br 2 I 2 + 2KBr  2KI + Br 2

Predicting the Outcomes of Chemical Reactions Predicting Double Displacement Outcomes Predicting Double Displacement Outcomes Need solubility rules handout. Need solubility rules handout. A dbl displacement reaction will occur if at least one of its products is insoluble. A dbl displacement reaction will occur if at least one of its products is insoluble.

Predicting the Outcomes of Chemical Reactions Predict whether a chem. rxn will occur in each of the following cases, and if it does, what products it will form. Predict whether a chem. rxn will occur in each of the following cases, and if it does, what products it will form. NaOH + Cu(NO 3 ) 2  ??? NaOH + Cu(NO 3 ) 2  ??? Two possible products: NaNO 3 and Cu(OH) 2 Two possible products: NaNO 3 and Cu(OH) 2 NaNO 3 is soluble, but Cu(OH) 2 is not. NaNO 3 is soluble, but Cu(OH) 2 is not. This reaction will proceed. This reaction will proceed. KCl + Fe(NO 3 ) 3  ??? KCl + Fe(NO 3 ) 3  ??? Two possible products: KNO 3 and FeCl 3 Two possible products: KNO 3 and FeCl 3 KNO 3 and FeCl 3 are both soluble. KNO 3 and FeCl 3 are both soluble. There will be no chemical reaction. There will be no chemical reaction.

Predicting the Outcomes of Chemical Reactions Would you expect each of the following chemical reactions to occur as written? Would you expect each of the following chemical reactions to occur as written? BaCl 2 + (NH 4 ) 2 SO 4  BaSO 4 + 2NH 4 Cl BaCl 2 + (NH 4 ) 2 SO 4  BaSO 4 + 2NH 4 Cl AgNO 3 + KBr  AgBr + KNO 3 AgNO 3 + KBr  AgBr + KNO 3 LiCl + NaOH  LiOH + NaCl LiCl + NaOH  LiOH + NaCl 3CaS + 2Fe(C 2 H 3 O 2 ) 3  3Ca(C 2 H 3 O 2 ) 2 + Fe 2 S 3 3CaS + 2Fe(C 2 H 3 O 2 ) 3  3Ca(C 2 H 3 O 2 ) 2 + Fe 2 S 3 3K 2 CO 3 + 2Na 3 PO 4  2K 3 PO 4 + 3Na 2 CO 3 3K 2 CO 3 + 2Na 3 PO 4  2K 3 PO 4 + 3Na 2 CO 3 K 2 CO 3 + CuI 2  2KI + CuCO 3 K 2 CO 3 + CuI 2  2KI + CuCO 3