Name: ___________________________
Period: ______
Date: ______________
WS 7.2: Harder Balancing Problems
Directions: Balance the following chemical equations using pencil. The physical states (“s” for solid, “l” for liquid, “g” for gas, and
“aq” for aqueous) are given in many problems but don’t effect balancing either. The problems at the end with a “**” are extremely
challenging and of greater difficulty than the problems you will have on an assessment. You should try them if you like a challenge
and you have extra class time.
1) C2H6(g) + O2(g)  CO2(g) + H2O(g)
2) NaN3(s)  Na(s) + N2(g)
3) Na + Fe2O3  Na2O + Fe
4) Mg(s) + N2(g)  Mg3N2(s)
5) Na + NH3  NaNH2 + H2
6) Na2O + CO2 + H2O  NaHCO3
7) P4S3(s) + O2(g)  P4O6(g) + SO2(g)
8) C6H14(l) + O2(g)  CO2(g) + H2O(g)
9) Na3PO4 + CaCl2  Ca3(PO4)2 + NaCl
10)
C8H18(l) + O2(g)  CO2(g) + H2O(g)
11)
C2H6O(l) + O2(g)  CO2(g) + H2O(g)
12)
Pb(NO3)2 + KI  PbI2 + KNO3
13)
N2O5  NO2 + O2
14)
KClO3(s)  KCl(s) + O2(g)
15)
CO(g) + O2(g)  CO2(g)
16)
C57H110O6(s) + O2(g)  CO2(g) + H2O(l)
17)
Na + O2  Na2O + Na2O2
18)
Al + H2SO4  Al2(SO4)3 + H2
19)
C7H10N + O2  CO2 + H2O + NO2
20)
Al(OH)3 + H2SO4  Al2(SO4)3 + H2O
21)
P4O6 + H2O  H3PO3
**22) K2MnF6 + SbF5  KSbF6 + MnF3 + F2
**23) S + HNO3  H2SO4 + NO2 + H2O
**24) Cu + HNO3  Cu(NO3)2 + NO + H2O
**25) CuS + HNO3  CuSO4 + NO2 + H2O
**26) Cu2S + HNO3  Cu(NO3)2 + CuSO4 + NO2 + H2O
**27) NaBr + NaBrO3 + H2SO4  Br2 + Na2SO4 + H2O
**28) KNO3 + C12H22O11  N2 + CO2 + H2O + K2CO3