CLASSIFICATION OF CHEMICAL REACTIONS NOTES
Depending on the nature of the reactants (reagents) and products, we can classify the chemical reactions in different types as follows:
Decomposition:
A decomposition reaction is the opposite of a synthesis reaction – a complex molecule breaks down to make simpler ones. These reactions come in the general form:
ABC ⇒ AC + B
ABC represents a compound and AC represents a compound and B represents an element.
In the decomposition process one product leads to several elements, or several compounds or a mixture of elements and compounds.
One example of a decomposition reaction is the decomposition of Mercury(II) oxide to make oxygen gas and metallic mercury:
2 HgO ⇒ 2 Hg + O2
Synthesis:
A synthesis reaction is when two or more simple compounds combine to form a more complicated one. These reactions come in the general form:
AC + B ⇒ ABC
ABC represents a compound and AC represents a compound and B represents an element.
In the synthesis process several elements, or several compounds or a mixture of elements and compounds lead to only one compound.
One example of a synthesis reaction is the combination of iron and sulfur to form iron (II) sulfide:
8 Fe + S8 ⇒ 8 FeS
Single displacement:
During a single displacement reaction, a more reactive element displaces a less reactive one from a compound.
A + BC ⇒ AC + B
A is more reactive than B so it is displaced from the compound.
Copper is more reactive than silver. If we place a copper wire in a colorless silver nitrate solution, copper will displace silver ions and will form blue copper (II) nitrate solution and silver needles can be observed on the copper surface.
Cu + 2 AgNO3 ⇒ Cu(NO3)2 + 2 Ag
Double displacement:
This is when the anions and cations of two different molecules switch places, forming two entirely different compounds. These reactions are in the general form:
AB + CD ⇒ AD + CB
One example of a double displacement reaction is the reaction of lead (II) nitrate with potassium iodide to form lead (II) iodide and potassium nitrate:
Pb(NO3)2 + 2 KI ⇒ PbI2 +2 KNO3
Combustion:
A combustion reaction is when oxygen combines with another compound to form water and carbon dioxide. These reactions are exothermic, meaning they produce heat. An example of this kind of reaction is the burning of naphthalene:
CxHy + O2 ⇒ CO2 + H2O
C10H8 + 12 O2 ⇒ 10 CO2 + 4 H2O
or ethanol
C2H5OH + 3 O2 ⇒ 2 CO2 + 3 H2O
Acid-base or Neutralization:
This is a special kind of double displacement reaction that takes place when an acid and base react with each other. The H+ ion in the acid reacts with the OH– ion in the base, causing the formation of water. Generally, the product of this reaction is some ionic salt and water:
HA + BOH ———> BA + H2O
H-acid + OH-Base ———> salt + water
One example of an acid-base reaction is the reaction of hydrochloric acid (HCl) with sodium hydroxide:
HCl + NaOH —> NaCl + H2O
Exercises
Name: ________________________
period ____ Date: ___________
Chemistry: Balancing naming compounds and classification of chemical Equations
Balance the equation. In the space below, write the word equation classification
1. ____ Sb + ____ Cl2 –> ____SbCl3
NAMES:
2. ____ Mg + ____O2 –> ____MgO
NAMES:
3. ____ CaCl2 –> ____ Ca + ____ Cl2
NAMES:
4. ____ NaClO3 –> ____ NaCl + ____ O2
NAMES:
5. ____ Fe + ____ HCl –> ____ FeCl2 + ____ H2
NAMES:
6. ____ CuO + ____ H2 –> ____ Cu + ____ H2O
NAMES:
7. ____ Al + ____ H2SO4 –> ____ Al2(SO4)3 + ____ H2
NAMES:
8. ____ MgBr2 + ____ Cl2 –> ____ MgCl2 + ____ Br2
NAMES:
9. ____ SnO2 + ____ C –> ____ Sn + ____ CO
NAMES:
10. ____ Pb(NO3)2 + ____ H2S –> ____ PbS + ____ HNO3
NAMES:
11. ____ HgO –> ____ Hg + ____ O2
NAMES:
12. ____ KClO3 –> ____ KCl + ____ O2
NAMES:
13. ____ N2 + ____ H2 –> ____ NH3
NAMES:
14. ____ NaBr + ____ Cl2 –> ____ NaCl + ____ Br2
NAMES:
15. ____ Zn + ____ AgNO3 –> ____ Zn(NO3)2 + ____ Ag
NAMES:
16. ____ Sn + ____ Cl2 –> ____ SnCl4
NAMES:
17. ____ Ba(OH)2 –> ____ BaO + ____ H2O
NAMES:
18. ____ Mg(OH)2 + ____ HCl –> ____ MgCl2 + ____ H2O
NAMES:
19. ____ Na2CO3 + ____ HCl –> ____ NaCl + ____ H2CO3
NAMES:
20. ____ NH4NO2 –> ____ N2 + ____ H2O
NAMES:
21. ____ N2 + ____ O2 –> ____ N2O5
NAMES:
22. ____ MgCO3 –> ____ MgO + ____ CO2
NAMES:
23. ____ KBr + ____ Cl2 –> ____ KCl + ____ Br2
NAMES:
24. ____ Zn + ____ CuSO4 –> ____ Cu + ____ ZnSO4
NAMES:
25. ____ P + ____ O2 –> ____ P4O6
NAMES:
26. ____ AgNO3 + ____ (NH4)2CrO4 –> ____ Ag2CrO4 + ____ NH4NO3
NAMES:
27. ____ K + ____ H2O –> ____ KOH + ____ H2
NAMES:
28. ____ Al + ____ Pb(NO3)2 –> ____ Al(NO3)3 + ____ Pb
NAMES:
29. ____ Fe + ____ O2 –> ____ Fe3O4
NAMES:
30. ____ Fe3O4 + ____ H2 –> ____ Fe + ____ H2O
NAMES: