1. 7.2 Types of Reactions Key Concepts
What are the general types of chemical reactions?
How did the discovery of subatomic particles affect the classification of reactions?
A chemical reaction is used to test for the presence of calcium carbonate in rock

2. Major Classes of Reactions
In order to understand chemical reactions, it is helpful to _____________ them.
There are ________ major categories of chemical reactions that scientists recognize….
______________
___________ _______________
_____________________
classify
five
synthesis
decomposition
single
replacement
double
replacement
combustion

3. General Equation: A + B  AB
Synthesis Reactions
In a synthesis reaction, two or more substances _______________ to form a ____________ product
General Equation: A + B  AB
combine
single

4. Synthesis Reactions
When iron rusts, iron metal and oxygen gas combine to form one new substance, _________________.
iron(III) oxide
If the two reactants were dancers, what would they be doing during a synthesis reaction?
Joining to dance together

5. Decomposition Reactions
In a decomposition reaction, a compound _________ _________ into two or more ___________ substances.
General Equation: AB  A + B
breaks
down
simpler

6. Decomposition Reactions
The decomposition reaction shown demonstrates that it has ______ reactant, but _______ products
one
two
If the initial compound represents two joined dancers, what would they do during a decomposition reaction?
Break apart to dance solo

7. Single-Replacement Reactions
In a single-replacement reaction, one ____________ takes the __________ of another element in a ________________.
General Equation: A + BC  B + AC
place
element
compound

8. Single Replacement Reactions
The single replacement reaction below shows the reaction between iron, Fe, and an aqueous solution of copper(II) sulfate, CuSO4.
Which element does iron, Fe, replace?
Copper, Cu

9. Single-Replacement Reactions
Imagine that the reactants below represent three dancers
One is dancing solo (element)
Two are dancing together (compound)
What would these dancers do during a single replacement reaction?
The solo dancer would cut in and take another
dancer’s place

10. Double-Replacement Reactions
In double-replacement reactions, the __________ portions of two ionic compounds are _______________
positive
interchanged
Review Question! When writing the formula for an ionic compound, like NaCl, do you place the positive ion first or second?
First… Na+ Cl-

11. Double-Replacement Reactions
General Equation: AB + CD  AD + CB
Notice that the general equation for a double-replacement reaction always has ______ compounds on the ____________ side and _____ compounds on the ____________ side
two
reactant
two
product

12. Double Replacement Reactions
Look at the double-replacement reaction below…
On the reactant side, what are the two positive ions?
What happens to them on the product side?
If this reaction represented two pairs of dancers, what would they do?
Pb2+ and K+
They switch compounds
They would trade partners

13. Review Question! What elements are found in a hydrocarbon?
Combustion Reactions
A combustion reaction is one in which a substance, normally a ______________, combines rapidly with ___________
hydrocarbon
oxygen
oxygen
Hydrocarbon
Review Question! What elements are found in a hydrocarbon?
hydrogen and carbon

14. What other two products are formed during combustion reactions?
Combustion reactions are exothermic, so one of their products is ______________
energy
What other two products are formed during combustion reactions?
H2O and CO2

15. Redox Reactions
After _____________ were discovered, scientists also began to classify certain reactions as a ______________ of electrons between atoms
A reaction in which electrons are transferred from one reactant to another is called an _____________ - _____________ reaction or a _______ reaction
electrons
transfer
oxidation
reduction
redox

16. Reactions as Electron Transfers
Calcium oxide, or lime, is produced when calcium burns in the presence of oxygen. In this reaction, the calcium is __________ and the oxygen is ____________.
2Ca + O2  2CaO
oxidized
reduced
Calcium oxide

17. Oxidation specifically involves the ______ of electrons
Reduction specifically involves the ________ of electrons
Hint…LEO the lion goes GER
LEO = losing electrons oxidation
GER = gaining electrons reduction
loss
Ca  Ca2+ + 2e–
gain
O + 2e–  O2–

18. Review Question Correctly identify each type of reaction shown.
Single-replacement
decomposition

19. combustion
synthesis
double-replacement

20. O + 2e–  O2– (gaining electrons)
Ca  Ca2+ + 2e– (losing electrons)
oxidation
O + 2e–  O2– (gaining electrons)
reduction