AP Chemistry - Simple Sight Equations and Word Equations
1.  When sulphur trioxide (SO3), which is present in smoggy air in trace concentrations,  reacts with water, sulphuric acid (H2SO4), a very corrosive acid, forms as the only  product. Write a balanced equation for this reaction and describe its stoichiometry in  words.
2. Write the equation that expresses in acceptable chemical shorthand the information given in the statement, "Iron can be made to react with molecular oxygen to give iron oxide having the formula Fe2O3."
3. Balance the following skeleton equations:

(a)    SO2 +   O2 --->   SO3                            (e)    N2 +    H2  ---->    NH3

(b)    Mg +   O2 -->   MgO                            (f)      P  +    O2 ------->   P4O10

(c)    NO +   O2 --->   NO2                            (g)     KClO4 -------->    KCl +    O2

(d)    HgO -------->    Hg +   O2                     (h)     PbO2 -------->    PbO +    O2
4. Write the balanced equation for the formation of table salt, NaCl (sodium chloride), from sodium (Na), and gaseous chlorine (Cl2).
5. Although bright and shiny, aluminum objects are covered with a tight, invisible coating of aluminum oxide, (Al2O3) that forms when freshly exposed aluminum (Al) reacts with oxygen. Write the balanced equation for this reaction.
6. Balance these equations.

a)    Sn(s) +   O2(g) ----->   SnO(s)

b)    Ca(s) +   Br2(g) ---->   CaBr2(s)

c)    P4(s) +   Cl2(g) ---->   PCl5(g)

d)    C(s) +   O2(g)  ---->   CO2(g)
7. Balance the following equations.

a)     Zn +   S ----->    ZnS                                   e)     Na +   O2 ----->    Na2O

b)     H2 +   P ----->    PH3                                  f)     O2 ----->     O3

c)     As +   O2 ----->    As2O3                            g)     As +   H2 ----->     AsH3

d)     H2 +   S ----->    H2S                                  h)     Sb +   O2 ----->     Sb2O3