1. Classifying Chemical
Reactions

2. Synthesis Reactions
• A chemical reaction in which 2 or more
substances ( A and B) react to produce a
single product (AB)
• A+B AB

3. • When 2 elements react it is always
synthesis
• 2 compounds can combine to form one
compound
– CaO (s) + H2O (l) Ca(OH)2
• A compound and an element can combine
– 2SO2 (g) + O2 (g) 2SO3 (g)

4. Combustion Reactions
• Oxygen combines with a substance and
releases energy in the form of heat and
light

5. • Combustion reactions are common
• Combustion reactions can be synthesis
reactions, but not all are
• Coal is burned to produce energy and
comprised of carbon. Below is the
equation for this combustion reaction:
– C (s) + O2 (g) CO2 (g)
– CH4 (g) + 2O2 (g) CO2 (g) + 2H2O (g)

6. Write the chemical Equations for
these reactions then classify
1. The solids aluminum and sulfur react to
produce aluminum sulfide
2. Water and dinitrogen pentoxide gas
react to produce aqueous hydrogen
nitrate
3. The gases nitrogen dioxide and oxygen
react to produce dinitrogen pentoxide
gas

7. Decompisition Reactions
• A single compound breaks down into 2 or
more elements or new compounds
• AB A+B

8. • Require an energy source
– Heat, light or electricity
• A real life example is an air bag activating
• Sodium Azide decomposes producing
nitrogen gas to inflate the bag
• 2NaN3 (s) 2Na (s) + 3N2 (g)

9. Write the Chemical Equations for
the following
• Aluminum oxide (s) decomposes when
electricity passes through it
• Nickel (II) hydroxide (s) decomposes to
produce nickel (II) oxide (s) and water

10. Single Replacement Reactions
• A reaction in which the atoms of one
element replace the atoms of another
element
• They “swap spots”

11. • Metal replaces hydrogen or another metal
– One metal replaces another metal in a compound
dissolved in water
– Copper is placed in aqueous silver nitrate.
– Crystals made of silver accumulate on the copper
bar
– Cu (s) + 2AgNO3 (aq)
2Ag (s) + Cu(NO3)2 (aq)

12. • A metal will not always replace another metal in
a compound dissolved in water because metals
differ in their reactivities
• Reactivity is the ability to react with another
substance

13. • A metal can replace
any metal below it
that is in a compound
• Example:
Silver wire in a copper
(II) nirate solution will
not produce a reaction
• We use NR if there is
no reaction
• Ag(s) + Cu(NO3)2 (aq)
NR

14. • Nonmetal replaces nonmetal
– Frequently involves halogens
– A more reactive halogen replaces a less reactive
halogen that is part of a compound dissolved in
water (aqueous)
– Fluorine replaces bromine in water containing
dissolved sodium bromide
• F2 (g) + 2NaBr (aq) 2NaF(aq) + Br2(l)
– Bromine DOES NOT replace fluorine in water
containing dissolved sodium fluoride
• Br2 (g) + 2NaF (aq) NR

15. Predicting the Products
1. Determine if the reaction will occur
2. Determine the products of the reaction
3. Write a skeleton equation
4. Balance

16. Fe(s) + CuSO4(aq) ?
1. Iron is placed in copper sulfate.
2. Iron is above copper in the activity series
3. Iron will replace copper
Fe(s) + CuSO4(aq)
FeSO4 (aq) + Cu (s)

17. Br2 (l) + MgCl2 (aq) NR
1. Bromide is placed in magnesium chloride
2. Chlorine is more reactive than Bromide
3. A reaction will not occur

18. Mg(s) + AlCl3 (aq)
• Magnesium is placed in Aluminum
Chloride
• Magnesium is more reactive than
aluminum
• See if you can figure out the answer
– Remember to CRISS CROSS for ionics!

19. Double Replacement Reactions