This document defines and describes chemical reactions. It explains that in a chemical reaction, atoms rearrange to form new compounds, with old bonds breaking and new bonds forming. Chemical reactions can be represented by chemical equations that show the reactants and products. Reactions can be exothermic, releasing energy, or endothermic, absorbing energy. They can also vary in reaction rate. The document also covers the law of conservation of matter, balancing chemical equations, and the main types of chemical reactions: synthesis, decomposition, single replacement, double replacement, and combustion reactions.
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Ppt chemical reactions
2. Chemical Reaction
What is a chemical
reaction?
• Atoms rearrange to create one or more
new compounds.
• In other words, old bonds break and
new bonds form.
9. Exothermic- release of energy.
Exo- Think exit!
Thermic – heat
Endothermic- absorption of
energy
Endo- Taken in
Thermic – heat
Chemical Reactions can
be…
11. 2. Fast or slow
The speed of a chemical reaction is
different for all!
Depends on the reactants.
Chemical Reactions can
be…
13. Law of Conservation of
Matter
The law of conservation of matter
states that matter (mass) can neither
be created nor destroyed. It
can, however, can be rearranged.
In a chemical reaction, the mass of the
reactants must equal the mass of the
products.
14. Law of Conservation of
Matter
The law of conservation of matter
states that matter (mass) can neither
be created nor destroyed. It can,
however, can be rearranged.
In a chemical reaction, the mass of the
reactants must equal the mass of the
products.
WHAT
??????
15. Think of a Balance
Everything must be equal.
When matter goes through a physical or
chemical change, the amount (or mass) of
the substances that you begin with must
equal the amount (or mass) of the
substances that you end with.
BEFORE MASS MUST = THE AFTER MASS!
WHY you ask!!!!!!!
16. How do we balance
chemical equations?!?!?!
1.USE A PENCIL!!
2.Identify reactants and products
3. Make a Table!!!
17. EXAMPLE:
H2O2 O2 + H2O
How do we balance
chemical equations?!?!?!
How many of each element is in the
reactants?
How many of each element is in the
products?
Element w/o coeff. X coeff. Total Element w/o coeff. X coeff. Total
18. EXAMPLE:
KClO3KCl + O2
How do we balance
chemical equations?!?!?!
How many of each element is in the
reactants?
How many of each element is in the
products?
Element w/o coeff. X coeff. Total Element w/o coeff. X coeff. Total
19. EXAMPLE:
CH4 + O2 CO2 + H2O
How do we balance
chemical equations?!?!?!
How many of each element is in the
reactants?
How many of each element is in the
products?
Element w/o coeff. X coeff. Total Element w/o coeff. X coeff. Total
21. 1. Synthesis-
Two or more simple substances are combined to
form one new and more complex substance.
Types of Reactions
A + B AB
22. 1. Synthesis-
Two or more simple substances are combined to
form one new and more complex substance.
Types of Reactions
A + B AB
2Na + Cl2 2NaCl
23. 2. Decomposition Reaction-
A more complex substance breaks down into its more
simple parts.
Types of Reactions
AB A + B
24. 2. Decomposition Reaction-
A more complex substance breaks down into its more
simple parts.
Types of Reactions
AB A + B
H2O2 O2 + H2O
25. 3. Single-Replacement-
A free uncombined element replaces another combined
element in a compound.
Types of Reactions
AB + C AC + B
26. 3. Single-Replacement-
A free uncombined element replaces another combined
element in a compound.
Types of Reactions
AB + C AC + BLiCl + Br2LiBr + Cl2
27. 4. Double Replacement Reaction-
The reacting parts of two compounds switch places to
form two new compounds.
Types of Reactions
AB + CD AD + BC
28. 4. Double Replacement Reaction-
The reacting parts of two compounds switch places to
form two new compounds.
Types of Reactions
AB + CD AD + BC
CaF2 + LiSO4 CaSO4 + LiF
29. 5. Combustion Reaction- OR Burning Reaction
Involves the combination of a substance with oxygen to give
off heat and light.
Types of Reactions
AB + O2 Heat+ Light
30. 5. Combustion Reaction- OR Burning Reaction
Involves the combination of a substance with oxygen to give
off heat and light.
Types of Reactions
AB + O2 Heat+ Light
CH4 + O2 CO2 + H2O
31. Types of Reactions
Use the code below to classify each reaction.
S = Synthesis D = Decomposition SR = Single Replacement DR = Double Replacement
____ P + O2 → P4O10 ____ Mg + O2 → MgO
____ HgO → Hg + O2____ Al2O3 → Al + O2
____ Cl2 + NaBr → NaCl + Br2 ____ H2 + N2 → NH3