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20 terms

Holt Modern Chemistry Chapter 8 - Chemical Equations and Reactions

Also know: Symbols used in chemical equations, pg. 266, 2009 ed.
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chemical equation
represents, with symbols and formulas, the identities and relative molecular or molar amounts of the reactants and products in a chemical reaction.
precipitate
a solid that is produced as a result of a chemical reaction in solution and that separates from the solution
coefficient
a small whole number that appears in front of a formula in a chemical equation
word equation
an equation in which the reactants and products in a chemical reaction are represented by words
formula equation
represents the reactants and products of a chemical reaction by their symbols or formulas
reversible reaction
a chemical reaction in which the products re-form the original reactants
synthesis reaction
known as a composition reaction, two or more substances combine to form a new compound
decomposition reaction
a chemical reaction in which a single compound undergoes a reaction that produces two or more simpler substances
electrolysis
the decomposition of a substance by an electric current
single-displacement reaction / replacement reaction
chemical reaction in which one element replaces a similar element in a compound
double-displacement reaction
chemical reaction in which the ions of two compounds exchange places in an aqueous solution to form two new compounds
combustion reaction
chemical reaction in which a substance combines with oxygen, releasing a large amount of energy in the from of light and heat;
combustion synthesis generates its own energy to keep the reaction continuing
activity series
a list of elements organized according to the ease with which the elements undergo certain chemical reactions;
for metals, greater activity means a greater ease of loss of electrons to form positive ions;
for nonmetals, greater activity means a greater ease of gain of electrons, to form negative ions.
Indications of a Chemical Reaction
1. Evolution of energy as heat and light.
2. Production of a gas.
3. Formation of a precipitate.
4. Color change.
Characteristics of Chemical Equations
1. The equation must represent know facts.
2. The equation must contain the correct formulas for the reactants and products.
3. The law of conservation of mass must be satisfied.
Significance of a Chemical Equation
1. The coefficients of a chemical reaction indicate relative, not absolute, amounts of reactants and products.
2. The relative masses of the reactants and products of a chemical reaction can be determined from the reaction's coefficients.
3. The reverse reaction for a chemical equation has the same relative amounts of substances as the forward reaction.
Balancing Chemical Equations
1. Identify the names of the reactants and products, and write a word equation.
2. Write a formula equation by substituting correct formulas for the names of the reactants and the products.
3. Balance the formula equation according to the law of conservation of mass. - see steps on pg. 271
4. Count atoms to be sure that the equation is balanced.
Decomposition Reactions
1. Decomposition of binary compounds - the simpiliest type of decomposition reaction.
2. Decomposition of metal carbonates
3. Decomposition of metal hydroxides
4. Decomposition of metal chlorates
5. Decomposition of acids
Single-Displacement Reactions
1. Displacement of a metal in a compound by another metal
2. Displacement of hydrogen in water by a metal
3. Displacement of hydrogen in an acid by a metal
4. Displacement of halogens
Double-Displacement Reactions
1. Formation of a precipitate
2. Formation of a gas
3. Formation of water