Writing and Balancing Chemical Equations
Balancing chemical equations gets easier with practice. It is a basic guess-and-check method, often called
“Balancing by Inspection”.
Important notes:
Hydrogen gas = H2
Nitrogen gas = N2
Oxygen gas = O2
Fluorine gas = F2
Chlorine gas = Cl2
Bromine liquid = Br2
Iodine solid = I2
Unless otherwise
stated, water is in liquid form.
For each of the following word equations, write the skeleton equation and then balance the equation. Be sure to use
all proper symbols like (s), (l), (g), and (aq). If the skeleton equation is already provided, then simply balance the
equation by writing the correct coefficients in the blanks. If the equation is already balanced, write “Balanced”.
Example:
Hydrogen sulfide gas reacts with oxygen gas to yield sulfur dioxide gas and water.
Skeleton equation:
H2S(g) + O2(g) → SO2(g) + H2O(l)
Balanced equation:
2H2S(g) + 3O2(g) → 2SO2(g) + 2H2O(l)
(You need not write the equation twice, just balance the skeleton equation.)
PLEASE USE PENCIL!
PLEASE USE PENCIL!
1.
Liquid carbon disulfide reacts with oxygen gas to yield carbon dioxide gas and sulfur dioxide gas.
2.
Methane (CH4) gas reacts with oxygen gas to yield carbon dioxide gas and water.
3.
Solid zinc (Zn+2) sulfide reacts with oxygen gas to yield solid zinc oxide and sulfur dioxide gas.
4.
____ Na + ____ Cl2 → ____ NaCl
5.
____ Sr + ____ AuNO3 → ____ Sr(NO3)2 + ____ Au
6.
____ SO3 + ____ H2O → ____ H2SO4
7.
____ KOH + ____ H3PO4 → ____ K3PO4 + ____ H2O
8.
____ Li + ____ H2O → ____ LiOH + ____ H2
9.
____ Li2O + ____ H2O → ____ LiOH
10.
____ Hg(MnO4)2 + ____ Al2(Cr2O7)3 → ____ HgCr2O7 + ____ Al(MnO4)3
11.
____ Ba + ____ P4 → ____ Ba3P2
12.
____ F2 + ____ BiCl3 → ____ Cl2 + ____ BiF3
13.
____ Pb(NO3)4 + ____ K2S → ____ KNO3 + ____ PbS2
14. Water is decomposed with electricity to yield hydrogen gas and oxygen gas.
15. Solid magnesium reacts with oxygen gas to yield solid magnesium oxide.
16. Carbon dioxide gas reacts with water to yield solid glucose (C6H12O6) and oxygen gas.
17.
____ H3PO3 + ____ (NH4)2CrO4 → ____ (NH4)3PO3 + ____ H2CrO4
18. .
____ Sn(OH)2 → ____ SnO + ____ H2O
19.
____ H2SO4 → ____ SO3 + ____ H2O
20. .
____ P2O3 + ____ H2O → ____ H3PO3
21.
____ Zn(BrO3)2 + ____ Pb3(AsO4)4 → ____ Zn3(AsO4)2 + ____ Pb(BrO3)4
22.
____ Rb + ____ Al(IO4)3 → ____ RbIO4 + ____ Al
23. .
____ NaNO3 → ____ NaNO2 + ____ O2
24.
____ Fe(NO3)3 → ____ Fe2O3 + ____ NO2 + ____ O2
25.
____ Cd + ____ HF → ____ CdF2 + ____ H2
26.
____ Sn + ____ Cl2 → ____ SnCl2
27. Solid potassium fluoride reacts with aqueous sulfuric acid to yield aqueous potassium hydrogen sulfate
(KHSO4) and hydrogen fluoride gas.
28. Solid copper(II) oxide reacts with hydrogen gas to yield solid copper metal and water.
29. Solid manganese(IV) oxide reacts with hydrogen gas to yield solid manganese(II) oxide and water.
30.
____ (NH4)2C2O4 + ____ Hg3(PO3)2 → ____ HgC2O4 + ____ (NH4)3PO3
31.
____ K2CO3 + ____ MnCl4 → ____ KCl + ____ Mn(CO3)2
32.
____ Co2S3 + ____ O2 → ____ Co2O3 + ____ S
33.
____ (NH4)2SO4 + ____ Fe(NO3)3 → ____ NH4NO3 + ____ Fe2(SO4)3
34.
____ BaCO3 + ____ HClO3 → ____ Ba(ClO3)2 + ____ H2CO3
35.
____ K + ____ H2O → ____ H2 + ____ KOH
36.
____ Al + ____ HCl → ____ H2 + ____ AlCl3
37.
____ F2 + ____ AsCl3 → ____ Cl2 + ____ AsF3
38.
____ Al + ____ Pb(NO3)2 → ____ Pb + ____ Al(NO3)3
39.
____ Bi2S5 + ____ SbBr3 → ____ BiBr5 + ____ Sb2S3
40. Methane (CH4) gas reacts with water to yield carbon monoxide gas and hydrogen gas.
41. Carbon monoxide gas reacts with water to yield carbon dioxide gas and hydrogen gas.
42. Butane (C4H10) gas reacts with itself to yield liquid octane (C8H18) and hydrogen gas.
43.
____ Fe + ____ Ag2CrO4 → ____ Fe2(CrO4)3 + ____ Ag
44.
____ Cs + ____ H2O → ____ H2 + ____ CsOH
45.
____ Ni2(SO4)3 + ____ Na2CO3 → ____ Ni2(CO3)3 + ____ Na2SO4
46.
____ Ca(NO3)2 + ____ (NH4)3PO3 → ____ Ca3(PO3)2 + ____ NH4NO3
47.
____ LiI + ____ H3PO4 → ____ Li3PO4 + ____ HI
48.
____ Cl2 + ____ SbBr3 → ____ Br2 + ____ SbCl3
49.
____ Br2 + ____ HI → ____ I2 + ____ HBr
50.
____ H2SO4 + ____ Zn → ____ ZnSO4 + ____ H2
51.
____ Ba(NO3)2 + ____ NaOH → ____ Ba(OH)2 + ____ NaNO3
52.
____ Zn + ____ CuSO4 → ____ ZnSO4 + ____ Cu
53. Solid manganese(IV) oxide reacts with hydrogen gas to yield solid manganese(II) oxide and water.
54. Solid iron(III) oxide reacts with hydrogen gas to yield solid iron and water.
55. Solid copper(I) sulfide reacts with oxygen gas to yield solid copper(I) oxide and sulfur dioxide gas.
56.
____ Li + ____ O2 → ____ Li2O
57.
____ Hg2O → ____ Hg + ____ O2
58.
____ Fe2O3 + ____ Al → ____ Al2O3 + ____ Fe
59.
____ P2O3 + ____ H2O → ____ H3PO3
60.
____ Sb(NO3)3 → ____ Sb2O3 + ____ NO2 + ____ O2
61.
____ NH4NO3 + ____ HCl → ____ NH4Cl + ____ HNO3
62.
____ Na2O + ____ H2O → ____ NaOH
63.
____ KBr + ____ Cl2 → ____ KCl + ____ Br2
64.
____ N2O5 + ____ H2O → ____ HNO3
65.
____ K2O + ____ H2O → ____ KOH