1. Balance the following reactions and classify them as either ENDOTHERMIC or EXOTHERMIC
thermal energy + MgO (s)  Mg (s) + O2 (g)
ENDOTHERMIC
b) C3H8 (g) + O2 (g)  thermal energy + H2O (l) + CO2 (g)
EXOTHERMIC
c) NH4NO3(s)+ H2O (l)+thermal energy N2 (g) + H2(g) + O2(g)
d) C(s) + O2 (g)  CO2 (g) + thermal energy 3 2 4 5

2. a) Ca + N2  b) Al + Br2  c) Li + O2  d) Fe + I2  Ca+2 N-3 Ca3N2
The following reactions are examples of synthesis reactions. Complete the reactions by writing the formulas of the IONIC products, then balance the equations.
(remember : find the charges, crossover and eliminate the ones)
a) Ca + N2 
b) Al + Br2 
c) Li + O2 
d) Fe + I2 
Thus, 3 Ca + N2  Ca3N2; Al + 3 Br2  2 AlBr3;
4 Li + O2  2 Li2O; Fe + 3 I2  2 FeI3
Ca N-3
Ca3N2
Al Br-1
AlBr3
Li2O
Li O-2
FeI3
Fe+3 I-1

3. a) HCl  H2 + Cl2 b) H2O  H2 + O2 c) MgCO3  Mg + C + O2 2 2 2
Complete the following decomposition reactions, then balance the equations.
(each element in the compound will end up by itself – remember HOBr FINCl)
a) HCl  H2 + Cl2
b) H2O  H2 + O2
c) MgCO3  Mg + C + O2 2 2 2

4. In each of the following reactions balance the equation and indcate if they are synthesis, decomposition, single displacement or double displacement.
a) H2O + SO3  H2SO synthesis
b) Mg(OH)2 + 2 HNO3  Mg(NO3)2 + 2 H(OH) double displacement
c) FeCl3 + 3 NaOH  Fe(OH)3 + 3 NaCl double displacement
d) Cl2 + ZnI2  ZnCl2 + I single displacement
e) H2SO4 + Mg  MgSO4 + H2 single displacement
f) K2O + H2O  2 KOH synthesis
g) 2 NaClO3  2 NaCl + 3 O2 decomposition
h) 2 BCl3 + 3 H2S  B2S3 + 6 HCl double displacement
i) Pb(NO3)2  PbO + 2 NO2 + ½ O2 decomposition
j) 3 NaOH + H3PO4  Na3PO4 + 3 H(OH) double displacement