TYPES OF CHEMICAL REACTIONS There are five types

TYPES OF CHEMICAL REACTIONS

There are five types of chemical reactions you need to know: 1. 2. 3. 4. 5. Synthesis reactions Decomposition reactions Single displacement reactions Double displacement reactions Combustion reactions

By the end of this lesson you should be able to: ü Classify the type of reaction ü Predict the product(s) of the reaction ü Balance the final equation including state symbols

Some steps for doing reactions 1. Identify the type of reaction 2. Predict the product(s) using the type of reaction as a model 3. Balance it § Don’t forget about the diatomic elements! § (Br I N Cl H O F) For example, Oxygen is O 2 which is a compound

• Synthesis reactions occur when two substances (generally elements) combine and form a compound. (Sometimes these are called combination or addition reactions. ) reactant + reactant 1 product • Basically: A + B AB • Example: 2 H 2 + O 2 2 H 2 O • Example: C + O 2 CO 2

• Here is another example of a synthesis reaction

Predict the products. Write and balance the following synthesis reaction equations. • Sodium metal reacts with chlorine gas 2 Na(s) + Cl 2(g) 2 Na. Cl(s) • Solid Magnesium reacts with fluorine gas Mg(s) + F 2(g) Mg. F 2(s) • Aluminum metal reacts with fluorine gas 2 Al(s) + 3 F 2(g) 2 Al. F 3(s)

• Decomposition reactions occur when a compound breaks up into the elements or in a few to simpler compounds • 1 Reactant Product + Product • In general: AB A + B • Example: 2 H 2 O 2 H 2 + O 2

• Another view of a decomposition reaction:

• Carbonates and chlorates are special case decomposition reactions that do not go to the elements. • Carbonates (CO 32 -) decompose to carbon dioxide and a metal oxide • Example: Ca. CO 3 CO 2 + Ca. O • Chlorates (Cl. O 3 -) decompose to oxygen gas and a metal chloride • Example: 2 Al(Cl. O 3)3 2 Al. Cl 3 + 9 O 2 • There are other special cases, but we will not explore those in this year

Predict the products. Then, write and balance the following decomposition reaction equations: • Solid Lead (IV) oxide decomposes Pb. O 2(s) • Aluminum nitride decomposes Al. N(s)

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) Nitrogen monoxide Ba. CO 3(s) Co(s)+ S(s) (make Co be +3) NH 3(g) + H 2 CO 3(aq) NI 3(s)

• Single Replacement Reactions occur when one element replaces another in a compound. • A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-). element + compound A + BC AC + B (if A is a metal) OR A + BC BA + C (if A is a nonmetal) (remember the cation always goes first!) When H 20 splits into ions, it splits into H+ and OH-

• Another view:

§ To determine if a single replacement reaction will take place we must look at the reactivity of the elements involved. § Elements higher on the table will replace elements lower on the table. § Elements lower will NOT replace elements higher.

• Write and balance the following single replacement reaction equation: • Zinc metal reacts with aqueous hydrochloric acid Zn(s) +2 HCl(aq) Zn. Cl 2 + H 2(g) Note: Zinc replaces the hydrogen ion in the reaction

• Sodium chloride solid reacts with fluorine gas 2 Na. Cl + F 2 Na. F(s) + Cl 2(g) (s) 2(g) Note that fluorine replaces chlorine in the compound Aluminum metal reacts with aqueous copper (II) nitrate 2 Al(s) + 3 Cu(NO 3)2 (aq) 2 Al(NO 3)3(aq) + 3 Cu(s)

• Double Replacement Reactions occur when a metal replaces a metal in a compound a nonmetal replaces a nonmetal in a compound • Compound + compound+ compound • AB + CD AD + CB

• Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together • Example: Ag. NO 3(aq) + Na. Cl(s) Ag. Cl(s) + Na. NO 3(aq) • Another example: K 2 SO 4(aq) + Ba(NO 3)2(aq) 2 KNO 3(aq) + Ba. SO 4(s)

§ To determine if products are soluble in water (aq) or insoluble (form a solid precipitate) we use a solubility table.

Predict the products. Balance the equation 1. HCl(aq) + Ag. NO 3(aq) 2. Ca. Cl 2(aq) + Na 3 PO 4(aq) 3. Pb(NO 3)2(aq) + Ba. Cl 2(aq) 4. Fe. Cl 3(aq) + Na. OH(aq) 5. H 2 SO 4(aq) + Na. OH(aq) 6. KOH(aq) + Cu. SO 4(aq)

• Combustion reactions occur when a hydrocarbon reacts with oxygen gas. • This is also called burning!!! • In order to burn something you need the 3 things in the “fire triangle”: 1. A Fuel (hydrocarbon) 2. Oxygen 3. Something to ignite the reaction (spark)

• In general: • Cx. Hy + O 2 CO 2 + H 2 O • Products in combustion are ALWAYS carbon dioxide and water. (although incomplete burning does cause some byproducts like carbon monoxide) • Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C 8 H 18)

Edgar Allen Poe’s drooping eyes and mouth are potential signs of CO poisoning.

Example • C 5 H 12 (l) + 8 O 2(g) 5 CO 2(g) + 6 H 2 O(l) • Write the products and balance the following combustion reaction: • C 10 H 22 (l) + O 2 (g)

State the type of reaction, predict the products, and balance the following reactions: 1. Ba. Cl 2 + H 2 SO 4 2. C 6 H 12 + O 2 3. Zn + Cu. SO 4 4. Cs + Br 2 5. Fe. CO 3

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