# Balancing Chemical Equations - Stoichiometry

3.1 Balance:
a) Cu+O2>CuO
b) Fe+Cl2>FeCl3
c) C+Br2>CBr4

Solutions: Copy bal.expr. into "unbalanced equation" edit field and calculate.

3.2 Balance:
a) Zn+HCl>ZnCl2+H2
a) Al+HCl>AlCl3+H2
c) Sn+HCl>SnCl4+H2

Solutions: Copy bal.expr. into "unbalanced equation" edit field and calculate.

3.3 Alkane-oxygen combustion's generally forms CO2 and water. Balance:
a) CH4+O2>CO2+H2O
b) C2H6+O2>CO2+H2O
c) C3H8+O2>CO2+H2O

Solutions: Copy bal.expr. into "unbalanced equation" edit field and calculate.

3.4 Balance:
a) Na2CO3+HNO3>NaNO3+H2O+CO2
b) KClO3+S+H2O>Cl2+K2SO4+H2SO4
c) FeS2+O2>Fe3O4+SO2
d) Al(OH)3+H2SO4>Al2(SO4)3+H2O
e) KBr+MnO2+H2SO4>Br2+MnBr2+KHSO4+H2O
f) Na3SbS4+HCl>Sb2S5+H2S+NaCl
g) Cu+HNO3>Cu(NO3)2+NO+H2O
h) Ca3P2+H2O>Ca(OH)2+PH3
i) FeSO4+KMnO4+H2SO4>Fe2(SO4)3+MnSO4+K2SO4+H2O

Solutions: Copy bal.expr. into "unbalanced equation" edit field and calculate.

Balance - Stoichiometry

3.5 8 grams of C5H12 reacts with oxygen.
Balance:
C5H12+O2>CO2+H2O and determine:
a) How many grams of CO2 was formed in the reaction?
b) How many grams of H2O was formed in the reaction?
c) How many grams of O2 was used during the reaction?

Solutions:8gC5H12+O2>CO2+H2O Copy argumented bal.expr. into "unbalanced equation" edit field and calculate.

3.6 A piece of metallic iron (3g) was dissolved in conc.HCl (6 grams of 100% HCl). The reaction formed H2 and FeCl2.
Balance: Fe+HCl>FeCl2+H2 and determine
a) amount of formed FeCl2
b) amount of formed H2

Solutions: 3gFe+6gHCl>FeCl2+H2 Copy argumented bal.expr. into "unbalanced equation" edit field and calculate.

3.7 Balance: N2+H2>NH3 and determine how many grams of nitrogen and hydrogen used in a reaction forming 15.0 grams of NH3 .

Solution:N2+H2>15gNH3 Copy argumented bal.expr. into "unbalanced equation" edit field and calculate.

3.8 Balance following heated mixture reaction: As2S3+NaNO3+Na2CO3>Na3AsO4+Na2SO4+NaNO2+CO2
Determine:
a) Amount of As2S3, NaNO3 and Na2CO3 used forming 23.0 grams of Na3AsO4 ?
b) How much CO2 will be formed if the "raw material" for the reaction was 10.0 grams As2S3, 75.0 grams NaNO3 and 37.0 grams of Na2CO3 ?

Solutions:Modify balance expr. and calculate
a) As2S3+NaNO3+Na2CO3>23gNa3AsO4+Na2SO4+NaNO2+CO2
b) 10gAs2S3+75gNaNO3+37gNa2CO3>Na3AsO4+Na2SO4+NaNO2+CO2

3.9 Balance:
Na2CO3+HNO3>NaNO3+H2O+CO2
Determine:
a) How much carbon dioxide will be formed using 13.4 grams of sodium in Na2CO3 ?
b) How much H2O will be formed if Na2CO3 contains 3.4 grams of carbon and HNO3 contains 18.8 grams of nitrogen?
c) How many moles of NaNO3 will be formed if CO2 contains 12.3 grams of carbon.

Solutions:Modify balance expr.:
a)13.4gNa,Na2CO3+HNO3>NaNO3+H2O+CO2
b)3.4gC,Na2CO3+18.8gN,HNO3>NaNO3+H2O+CO2
c)Na2CO3+HNO3>NaNO3+H2O+12,3gC,CO2

3.10 Metallic iron may be produced by heating a mixture of Fe2O3 and carbon.
Balance:
Fe2O3+C>Fe+CO2
and determine moles of:
a) Fe2O3 in a reaction forming 1000 grams of Fe.
b) Fe in a reaction using 200 grams of C.
c) CO2 in a reaction forming 12.8 moles Fe.

Solutions:Modify balance expr.
a) Fe2O3+C>1000gFe+CO2
b) Fe2O3+200gC>Fe+CO2
c) Fe2O3+C>12.8mFe+CO2

3.11 FeS2 and O2 reacts forming Fe3O4 and SO2. Balance:
FeS2+O2>Fe3O4+SO2
Determine the amount of formed SO2 and Fe3O4 using 12.0 grams of Fe in FeS2 and 1.5 moles of O in O2?.

Solution:Modify balance expr.
12gFe,FeS2+1.5mO,O2>Fe3O4+SO2

3.12 KClO3 added HCl forms Cl2
Balance:
KClO3+HCl>H2O+KCl+Cl2
Determine:
a)Amount of KClO3 used in a reaction forming 2 grams of Cl2.
b)A compound (KClO3) contains 4 g oxygen. How much Cl2 will be formed adding 0.04 moles of HCl ?

Solutions:Modify balance expr.
a) KClO3+HCl>H2O+KCl+3gCl2
b) 4gO2,KClO3+0.04mHCl>H2O+KCl+Cl2

3.14 1 kg octane reacts with oxygen. Determine vol. O2 (NTP) used in this reaction.

Solution:Modify balance expr.
Step 1: 1000gC8H18 + O2 > CO2 +H2O
Step 2: Calculate O2 -vol. using V=nRT/p.
(n) moles of oxygen (calculated in Step 1):
(gass const.) R=0.082liter*atm/(Kelvin*mol)
(temp.) T=273.15Kelvin
(pressure) p=1atm.

3.15 10.99 grams of a compund containing C, H and O reacts with O2 forming H2O and 21.0 grams of CO2. What's the empiric formula for the compund?

Solution:Find the answer by observing the effect of varying the values of X,Y and Z in following argumented (21g) balance expression:
CXHYOZ + O2 > 21gCO2 + H2O