Chemical Equations. Chemical Reactions - OVERVIEW change that occurs when atoms rearrange themselves...
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Transcript of Chemical Equations. Chemical Reactions - OVERVIEW change that occurs when atoms rearrange themselves...
Chemical Equations
Chemical Reactions - OVERVIEW change that occurs when atoms
rearrange themselves Can absorb or release energy
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Chemical equations used to describe chemical reactions
What is an equation in math?
What does it look like?
Chemical equations in science are similar!
Think!
Chemical Equation describes a chemical reaction
C + O2 CO2, The carbon reacts with oxygen to yield
carbon dioxide.
Parts of a Chemical Equation
This reads “carbon reacts with oxygen react to yield carbon dioxide”
C + O2 CO2REACTANTS
Molecules that are used in the reaction.
PRODUCTSMolecules that are
formed in the reaction.
The arrow is read as “yields”
Identify the reactants and products:
Chemical Equation Name theElements
Name theREACTANTS
Name thePRODUCTS
2Na + Cl2 → 2NaCl Sodium, Chlorine
Sodium, Chlorine
Sodium Chloride (salt)
CO2 + H2 CH4 + H2O
2H2 + O2 2H2O
4Al + 3 O2 2Al2O3
Key: CH4 = methane, NaCl= Sodium Chloride, Al2O3 = Aluminum Oxide
Law of Conservation of Mass
Matter can not be created or
destroyed, although it may be
rearranged.
Lavoisier, 1788
Chemical EquationsBecause of
“Conservation of Mass”, chemical equations must be balanced
Must have same number of each element on both sides of equation
Lavoisier, 1788
2H2 + O2 2H2O What elements do you
have?
Balanced or Unbalanced?
HydrogenOxygen
HydrogenOxygen
A chemical equation must have the same number of atoms of each element on either
side of the arrow in order to be balanced
2H2 + O2 2H2O How many atoms of each elements
do you have?
Balanced or Unbalanced?A chemical equation must have the same type and amount of atoms on either side of the arrow in order to
be balanced
HydrogenOxygen
HydrogenOxygen
A chemical equation must have the same type and amount of atoms on either side of the arrow in order to
be balanced
= 4
= 2
= 4
= 2BALANCED
Al + Br2 Al2Br6 What elements do you have?
Balanced or Unbalanced?
AluminumBromine
AluminumBromine
Balanced or Unbalanced?
= 1
= 2 = 6
= 2
Al + Br2 Al2Br6
How many atoms of each elements do you have?
AluminumBromine
AluminumBromine
*UNBALANCED*
Chemical Reactions & Equations – PRACTICE!
K3PO4 + 2HCl 2KCl + H3PO4 Is this equation balanced?
K = 3P = 1
O = 4H = 2
K = 2P = 1O = 4H = 3
No: K and H are not the same on both
sides of the equation
Cl = 2
Cl = 2
Reactants = Products