Synthesis Reactions In a synthesis reaction also known

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Synthesis Reactions • In a synthesis reaction, also known as a composition reaction, two

Synthesis Reactions • In a synthesis reaction, also known as a composition reaction, two or more substances combine to form a new compound. • This type of reaction is represented by the following general equation: A + X → AX • A and X can be elements or compounds. • AX is a compound.

 • To visualize a synthesis reaction, look at the cartoon above. • A

• To visualize a synthesis reaction, look at the cartoon above. • A skinny bird (reactant) and the worm (reactant) combine to make one product, the fat bird.

 • Two or more reactants yielding one product is another way to identify

• Two or more reactants yielding one product is another way to identify a synthesis reaction. 2 Mg (s) + O 2 (g) → 2 Mg. O (s)

Example of a Synthesis Reaction

Example of a Synthesis Reaction

Decomposition Reactions • In a decomposition reaction, a single compound undergoes a reaction that

Decomposition Reactions • In a decomposition reaction, a single compound undergoes a reaction that produces two or more simpler substances. • Decomposition reactions are the opposite of synthesis reactions. • They are represented by the following general equation: AX → A + X • AX is a compound. • A and X can be elements or compounds.

 • To visualize a decomposition reaction, look at the cartoon above. • In

• To visualize a decomposition reaction, look at the cartoon above. • In this cartoon, the egg (reactant) which contained the turtle at one time, now has opened and the turtle (product) and egg shell (product) are now two separate substances.

 • A reaction with only one reactant and more than one product is

• A reaction with only one reactant and more than one product is another way to identify a decomposition reaction. H 2 CO 3 (aq) → CO 2 (g) + H 2 O (l) one reactant more than one product

Example of a Decomposition Reaction

Example of a Decomposition Reaction

Single-Displacement Reactions • In a single-displacement reaction, also known as a replacement reaction, one

Single-Displacement Reactions • In a single-displacement reaction, also known as a replacement reaction, one element replaces a similar element in a compound. • Many single-displacement reactions take place in aqueous solution. • Single-displacement reactions can be represented by the following general equations. A + BX → AX + B or Y + BX → BY + X • A, B, X, and Y are elements. AX, BX, and BY are compounds.

 • To visualize a single-displacement reaction, look at the above cartoon. • Notice

• To visualize a single-displacement reaction, look at the above cartoon. • Notice the guy in the orange shirt steals the date of the other guy. • So, a part of one of the reactants trades places and is in a different place among the products.

Example: 2 Al (s) + 3 Pb(NO 3)2 (aq) → 3 Pb (s) +

Example: 2 Al (s) + 3 Pb(NO 3)2 (aq) → 3 Pb (s) + 2 Al(NO 3)3 (aq) When solid aluminum is placed in a solution of lead(II) nitrate, the aluminum replaces the lead. Solid lead and aqueous aluminum nitrate are formed. Notice that the reactants are an element and a compound and the products are an element and a compound.

Example of a Single-Displacement Reaction

Example of a Single-Displacement Reaction

Double-Displacement Reactions • In double-displacement reactions, the ions of two compounds exchange places in

Double-Displacement Reactions • In double-displacement reactions, the ions of two compounds exchange places in an aqueous solution to form two new compounds. • One of the compounds formed is usually a precipitate, an insoluble gas that bubbles out of the solution, or a molecular compound, usually water. • The other compound is often soluble and remains dissolved in solution.

 • A double-displacement reaction is represented by the following general equation. AX +

• A double-displacement reaction is represented by the following general equation. AX + BY → AY + BX • A, X, B, and Y in the reactants represent ions. • AY and BX represent ionic or molecular compounds.

 • To visualize a double-displacement reaction, look at the cartoon above. • Notice

• To visualize a double-displacement reaction, look at the cartoon above. • Notice the “hats” have exchanged places.

Example: formation of a precipitate 2 KI (aq) + Pb(NO 3)2 (aq) → Pb.

Example: formation of a precipitate 2 KI (aq) + Pb(NO 3)2 (aq) → Pb. I 2 (s) + 2 KNO 3 (aq) “partners trade places” Lead(II) iodide

Example: formation of a gas Fe. S (s) + 2 HCl (aq) → H

Example: formation of a gas Fe. S (s) + 2 HCl (aq) → H 2 S (g) + Fe. Cl 2 (aq) “partners trade places”

Example: formation of water (molecular) HCl (aq) + Na. OH (aq) → Na. Cl

Example: formation of water (molecular) HCl (aq) + Na. OH (aq) → Na. Cl (aq) + H 2 O (l) “partners trade places”

Combustion Reactions • In a combustion reaction, a substance combines with oxygen, releasing a

Combustion Reactions • In a combustion reaction, a substance combines with oxygen, releasing a large amount of energy in the form of heat and light.

Examples: 2 H 2 (g) + O 2 (g) → 2 H 2 O

Examples: 2 H 2 (g) + O 2 (g) → 2 H 2 O (g) C 3 H 8 (g) + 5 O 2 (g) → 3 CO 2 (g) + 4 H 2 O (g) propane