Chemical Formulas & Equations
Matter and Energy
Level B
1.  Propane, C3H8, is a colorless, odorless gas often used as a heating and cooking fuel in
campers and rural homes. Write a balanced equation for the combustion reaction of propane
with oxygen to yield carbon dioxide and water.
Unbalanced equation: C3H8 + O2  CO2 + H2O
a.  Balance for C.
b.  Balance for C and H.
c.  Balance for C, H, and O.
Final balanced equation:
2.  The major ingredient in ordinary safety matches is potassium chlorate, KClO3, a substance that
can act as a source of oxygen in combustion reactions. Its reaction with ordinary table sugar
(sucrose, C12H22O11), for example, occurs violently to yield potassium chloride, carbon dioxide,
and water. Write a balanced equation for the reaction.
Unbalanced equation: KClO3 + C12H22O11  KCl + CO2 + H2O
a.  Balance for C.
b.  Balance for C and H.
c.  Balance for C, H, and O.
Final balanced equation:
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Chemical Formulas & Equations
Matter and Energy
Level B
3.  Balance the equation for the fermentation of sugar to yield ethyl alcohol.
C6H12O6  C2H6O + CO2
4.  Balance the equation for the photosynthesis reaction in green plants.
CO2 + H2O  C6H12O6 + O2
5.  Balance the equation for the synthesis of hydrazine for rocket fuel.
NH3 + Cl2  N2H4 + NH4Cl
6.  Which of the following equations are balanced?
a.  The development reaction in photography:
2AgBr + 2NaOH + C6H6O2  2 Ag + H2O + 2NaBr + C6H4O2
b.  Preparation of household bleach:
2NaOH + Cl2  NaOCl + NaCl + H2O
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