Chapter 6: Chemical Reactions
A. Chemical Reaction
 A change in which one or more substances are _____________________ to
__________________________ _____________________________.
A+B C+D
______________________
___________________________
B. Law of Conservation of Mass

In a chemical reaction, ___________________ is not _______________________ or
_____________________.

____________________ can only ____________________________.

Discovered by ________________________________.
_______ H
________ H
_______ O
________ O
C. Chemical Equations
 2 molecules of hydrogen gas plus oxygen gas produces 2 molecules of liquid dihydrogen
monoxide.
Coefficient - # of _____________________ of each substance

Describing ____________________________:

individual atom = “_________________________”
_______ ____________  2 _____________ of magnesium

_____________________ substance = “____________________”
3CO2  ____________________________________________________________________

_______________ substance = “unit”
1
____________________________  __________________ units of magnesium oxide
Symbol
Meaning
+
(s)
(l)
(g)
(aq)
Δ
I. Balancing Equations
A. Balancing Steps
1. Write the ______________________________ __________________________.
2. _____________________ __________________ on ______________________
______________________.
3. Add _______________________ to make #s ___________________________.
________________________ x ____________________________ = _______________________________
4. _______________ _____________________ to lowest possible ______________, if necessary.
5. Double check atom balance!!!
B. Balancing Example
Aluminum and copper (II) chloride form copper and aluminum chloride.
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II. Types of Reactions
A. Synthesis

the combination ___________________________________________________________________

only ________________ __________________________ forms
A + B  AB
______________________________________________________________________________
B. Decomposition

a compound __________________________________________________________________

only ___________________ _________________________
AB  A + B
______________________________________________________________________________
C. Single Replacement

one element replaces another in a compound

metal replaces metal (+)

nonmetal replaces nonmetal (-)
A + BC  AC + B
______________________________________________________________________________
D. Double Replacement

ions in two compounds “____________________ ________________________________”

_____________________ of one compound ________________ with _____________________
of the other
AB + CD  AD + CB
______________________________________________________________________________
E. Combustion

the ______________________ of a substance in_________________ to produce heat

hydrocarbons (CxHy) always form _____________ and ______________________
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CxHy +O2  CO2+H2O
______________________________________________________________________________
III. Energy & Chemical Reactions
A. Energy Changes
During a chemical reaction…

______________________ is used to ____________________ bonds

________________ is _____________________when ______________ _________________
are ____________________________
B. Exothermic Reaction

reaction that ___________________________ __________________________

energy released by making ___________________ _______________ bonds outweighs energy
required to break old bonds

reaction that powers the space shuttle lift-off
C. Endothermic Reaction

reaction that __________________________ ___________________________

energy required to _________________ ____________________ bonds outweighs energy
released by making new bonds

process used to obtain aluminum from aluminum ore
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