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Chapter 8 section 2

Terms in this set (28)

Five basic types of reactions
synthesis, decomposition, single-displacement, double-displacement, and combustion
Synthesis reaction
also known as a composition reaction, two or more substances combine to form a new compound.
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general equation of a synthesis reaction
A + X = AX
A and X can be elements or compounds. AX is a compound.
Reactions of elements with oxygen and sulfur
The combination of an element with oxygen to produce an oxide of the element. Almost all metals react with oxygen to form oxides. Group 2 elements react in a similar manner, forming oxides with the formula MO, where M represents the metal. The Group 1 metals form oxides with the formula Msubscript2O. The Group 1 and Group 2 elements react similarly with sulfur, forming sulfides with the formulas Msubscript2S and MS, respectively. Some metals combine with oxygen to produce two different oxides. Nonmetals also undergo synthesis reactions with oxygen to form oxides.
Reactions of Metals with Halogens
Most metals react with the Group 17 elements, the halogens, to form either ionic or covalent compounds. Group 1 metals react with halogens to form ionic compounds with the formula MX, where M is the metal and X is the halogen.
Group 2 metals react with the halogens to form ionic compounds with the formula MXsubscript2.
The halogens undergo synthesis reactions with many different metals. Fluorine in particular is so reactive that it combines with almost all metals.
Synthesis reactions with Oxides
Active metals are highly reactive metals. Oxides of active metals react with water to produce metal hydroxides. Many oxides of nonmetals in the upper-right portion of the periodic table react with water to produce oxyacids. Certain metal oxides and nonmetal oxides react with each other in synthesis reactions to form salts.
Decomposition reaction
a single compound undergoes a reaction that produces two or more simpler substances.
The opposite of a synthesis reaction
Most decomposition reactions take place only when energy in the form of electricity or heat is added.
General equation of a decomposition reaction
AX= A+X
AX is a compound. A and X can be elements or compounds.
Decomposition of Binary Compounds
The simplest kind of decomposition reaction is the decomposition of a binary compound into its elements.
Oxides of the less-active metals, which are located in the lower center of the periodic table, decompose into their elements when heated.
Electrolysis
The decomposition of a substance by an electric current
Decomposition of metal carbonates
When a metal carbonate is heated, it breaks down to produce a metal oxide and carbon dioxide gas.
Decomposition of metal hydroxides
all metal hydroxides except those containing Group 1 metals decompose when heated to yield metal oxides and water.
Decomposition of metal chlorates
When a metal chlorate is heated, it decomposes to produce a metal chloride and oxygen.
Decomposition of acids
Certain acids decompose into nonmetal oxides and water. Carbonic acid is unstable and decomposes readily at room temperature to produce carbon dioxide and water.
When heated, sulfuric acid decomposes into sulfur trioxide and water.
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. The amount of energy involved in this type of reaction is usually smaller than the amount involved in synthesis or decomposition reactions.
general equations of single-displacement reactions
A + BX = AX + B
Y + BX = BY + X
A, B, X, and Y are elements. AX, BX, and BY are compounds.
Displacement of Hydrogen in water by a metal
The most active metals, such as those in group 1, react vigorously with water to produce metal hydroxides and hydrogen.
Less-active metals react with steam to form a metal oxide and hydrogen gas.
Displacement of Hydrogen in an acid by a metal
The more-active metals react with certain acidic solutions, replacing the hydrogen in the acid. The reaction products are a metal compound ( a salt) and hydrogen gas.
Salt
Any ionic compound formed in the neutralization of an acid by a base.
Displacement of Halogens
one halogen replaces another halogen in a compound. Fluorine is the most-active halogen. As such, it can replace any of the other halogens in their compounds. Each halogen is less active than the one above it in the periodic table. Therefore, in Group 17 each element can replace any element below it, but not any element above it.
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.
general equation of a double-displacement reaction
AX + BY = AY + BX
A, X, B, and Y in the reactants represent ions. AY and BX represent ionic or molecular compounds.
Formation of a precipitate
The formation of a precipitate occurs when the cations of one reactant combine with the anions of another reactant to form an insoluble or slightly soluble compound.
spectator ions
ions that do not take part in the reaction
Formation of a gas
In some double-displacement reactions one of the products is an insoluble gas that bubbles out of the mixture.
Formation of water
In some double-displacement reactions, a very stable molecular compound, is one of the products.
Combustion reaction
a substance combines with oxygen, releasing a large amount of energy in the form of light and heat.
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