types of chemical reactions. review a chemical equation describes a chemical change. the law of...
TRANSCRIPT
Types of Chemical Reactions
ReviewA chemical equation describes a chemical
change.
The Law of Conservation of Mass says that the number and kind of atoms going INTO a chemical reaction must be the same as
the number and kind of atoms coming OUT.
Balancing an equation makes it obey the Law of Conservation of Mass.
The six types of chemical reactions we will discuss are:
SynthesisDecomposition
Single DisplacementDouble Displacement
Acid-BaseCombustion
Types of Reactions
Two or more substances combine to form one
substance.The general form is
A + X AX
Example:2Mg + O2 2MgO
Synthesis Reactions
Decomposition Reactions
One molecule breaks down to form two or more substances. The general form is
AX A + X
Example:2H2O 2H2 + O2
Single Displacement Reactions
A single element switches places with another element in a
chemical compound.
The general form is A + BX AX + B
Example:
Ni + 2AgNO3 2Ag + Ni(NO3)2
Example:
Ni + 2AgNO3 2Ag + Ni(NO3)2
Single Displacement Reactions
Ni + 2AgNO3 Nickel replaces the
metallic ion Ag+.
The silver becomes free silver and the nickel
becomes the nickel(II) ion.
Double Displacement Reactions
The cations of two compounds exchange
places with each other.
The general form is:AX + BY AY + BX
Double Displacement
Example:
NaOH + CuSO4
The Na+ and Cu2+ switch places.Na+ combines with SO4
2- to form Na2SO4.
Cu2+ combines with OH- to form Cu(OH)2
2NaOH + CuSO4 Na2SO4 + Cu(OH)2
Acid-BaseAcid-base reactions are double displacement reactions which takes place when an acid and
base react with each other.
HA + BOH → H2O + BA Acid Base
Example: HBr + NaOH → NaBr + H2OThe H+ ion in the acid reacts with the OH- ion in the
base, causing the formation of an ionic salt (NaBr) and water.
Combustion Reaction
When a compound containing carbon and hydrogen combines with oxygen, the products formed are heat, water,
and carbon dioxide.
CH4 + 2O2 CO2 + 2H2O
1) Does the reaction look like this: X + O2 CO2 + H2O ?
If yes - combustion reaction.
2) Is there only one product? If yes - synthesis reaction.
3) Is there only one reactant?If yes - decomposition reaction.
4) Are any reactants only one kind of element?
If yes - single displacement reaction.
5) Is water a product of this reaction? If yes - acid base reaction.
If not - double displacement reaction.
Learning Check...Classify each of the following
reactions:
H2 + Cl2 2HCl
Synthesis
Ca + 2H2O Ca(OH)2 + H2
Single displacement
Classify each of the following reactions:
2CO + O2 2CO2
Synthesis
2KClO3 2KCl + 3O2
Decomposition
Learning Check...
Classify each of the following reactions:
CH3SH + 3O2 CO2 + 2H2O + SO2
Combustion
Zn + 2HCl ZnCl2 + H2
Single displacement
Learning Check...