Ch 8 - Chemical Reactions

Types of Reactions There are five types of chemical reactions we will talk about: Combination (or synthesis) reactions Decompositition reactions Single replacement reactions Double replacement reactions Combustion reactions You need to be able to identify the type of reaction and predict the product(s)

1. Combination reactions Combination reactions occur when two substances (generally elements) combine and form a compound. reactant + reactant 1 product A + B AB Example: 2H 2 + O 2 2H 2 O Example: C + O 2 CO 2

Combination Reactions Here is another example of a combination reaction

Practice Complete and balance: Sodium metal reacts with chlorine gas Na (s) + Cl 2(g) Solid Magnesium reacts with fluorine gas Mg (s) + F 2(g) Aluminum metal reacts with fluorine gas Al (s) + F 2(g)

2. Decomposition Reactions Decomposition reactions occur when a compound breaks up into elements 1 Reactant Product + Product AB A + B Example: 2 H 2 O 2H 2 + O 2 Example: 2 HgO 2Hg + O 2

Decomposition Reactions Another view of a decomposition reaction:

Practice Complete and balance: Solid Lead (IV) oxide decomposes Aluminum nitride decomposes

Practice Identify the type of reaction for each of the following synthesis or decomposition reactions, and write the balanced equation: N 2(g) + O 2(g) BaCl 2(s) Co (s) + S (s) NI 3(s) (make Co be +3) Nitrogen monoxide

3. Single Replacement Reactions Single Replacement Reactions occur when one element replaces another in a compound. Element A + compd BC element B + Compd AC A + BC AC + B (if A is a metal) A + BC BA + C (if A is a halogen) H 2 O H + and OH - (not H+ and O -2 !!)

Single Replacement Reactions Another view:

Single Replacement Reactions Complete and balance: Zinc metal reacts with hydrochloric acid Zn (s) + HCl (aq) ZnCl 2 + H 2(g) Note: Zinc replaces the hydrogen ion in the reaction 2

Single Replacement Reactions Sodium chloride solid reacts with fluorine gas NaCl (s) + F 2(g) NaF (s) + Cl 2(g) Aluminum reacts with aqueous copper (II) nitrate 22

4. Double Replacement Reactions Double Replacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound AB + CD AD + CB

Double Replacement Reactions Think about it like foiling in algebra, first and last ions go together + inside ions go together Example: AgNO 3(aq) + NaCl (s) AgCl (s) + NaNO 3(aq) Another example: K 2 SO 4(aq) + Ba(NO 3 ) 2(aq) KNO 3(aq) + BaSO 4(s) 2

Solubility Table

Practice Predict the products. Balance the equation HCl (aq) + AgNO 3(aq) CaCl 2(aq) + Na 3 PO 4(aq) Pb(NO 3 ) 2(aq) + BaCl 2(aq) FeCl 3(aq) + NaOH (aq) H 2 SO 4(aq) + NaOH (aq) KOH (aq) + CuSO 4(aq)

1. 1. CaCl 2(aq) + Na 3 PO 4(aq) Pb(NO 3 ) 2(aq) + BaCl 2(aq)

5. Combustion Reactions Combustion reactions occur when a hydrocarbon reacts with oxygen gas.

Combustion Reactions For burning hydrocarbons: C n H n+2 + O 2 CO 2 + H 2 O Products of complete combustion are ALWAYS carbon dioxide and water.

Combustion Reactions Edgar Allen Poes drooping eyes and mouth are potential signs of CO poisoning.

Combustion Example: C 5 H 12 + O 2 CO 2 + H 2 O Complete and balance: C 10 H 22 + O

Mixed Practice State the type, predict the products, and balance the following reactions: BaCl 2 + H 2 SO C 6 H 12 + O Zn + CuSO Cs + Br FeCl 3