Chemical Reactions

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Chemical Reactions
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• In chemical reactions, one or more substances

change into different substances.
example combustion
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Word Equations and Chemical Equations

• Chemists use equations to describe chemical
  reactions.
• Word equations show the names of the materials in
  the chemical reaction.
• Chemical equations show the chemical formulas of
  the materials in the chemical reaction.

REACTANT
PRODUCTS
(starting materials) (yields) (ending materials)
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• Word equation

sodium chlorine sodium chloride
Chemical equation
Na Cl NaCl
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Common State Symbols in Chemical Equations
State Symbol Meaning Example
Solid
Liquid
Gaseous
Aqueous (dissolved in water)
(s)
(sodium chloride) NaCl(s)
(l)
(bromine) Br2(l)
(g)
(hydrogen) H2(g)
(aqueous sodium chloride solution)
NaCl(aq)
(aq)
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Lets go back to the example we used

• Word Equation

sodium(s) chlorine(g) sodium
chloride(s)
Chemical Equation
Na(s) Cl2(g) NaCl(s)
sodium
sodium chloride
chlorine
chemical reaction
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Word Equation

• zinc (s) copper(II) sulphate (aq)

zinc sulphate (aq) copper (s) energy
Chemical Equation
Zn(s) CuSO4(aq)
ZnSO4(aq) Cu(s) energy
zinc
copper(II) sulphate
zinc sulphate
copper