I am stuck on balancing a chemical equation using algebraic method. Can you please help me

by using the same method. ( It is a Language of Chemistry question, but not accepting since there is no option to be selected on Topic)
 

Cu2S + HNO3 -> Cu(NO3)2 + H2SO4 + NO + H20

Asked by Shoumik | 22nd Jul, 2015, 07:00: AM

Expert Answer:

aCu2S + bHNO3 →c Cu (NO3)2 + dH2SO4 + eNO +f H2O

 

Cu: 2a = c------------------------------------(1)

S: a = d------------------------------------(2)

H: b= 2d +2f------------------------------------ (3)

N: b=2c + e------------------------------------(4)

O: 3b = 6c + 4d+e+f------------------------------------(5)

Substituting the value for a from 2nd eqn into 1st eqn

2d = c
Substituting  the value of 2d into the 3rd eqn
b = c + 2f
Substituting  the value of 2d in eqn 5
3b = 8c + e + f
Now , c + 2f = 2c + e
2f = c + e
Substituting the value b = 2c + e  in eqn 3b = 8c + e + f
6c + 3e = 8c + e + f
2e = 2c + f
f = 2e - 2c
 

Substituting the value of  f in 2f = c + e
4e - 4c = c + e
3e = 5c
e = 5 and c = 3
Substituting the values of c and e in f = 2e - 2c
f = 10 - 6 = 4
Substituting the values of c and f in b = c + 2f
b = 3 + 8 = 11
Substituting the value of c in 2d = c
2d = 3
d = 3/2
Substituting the value of c in 2a = c
2a = 3
a = 3/2
 So a = 3/2, b = 11, c = 3, d = 3/2, e = 5, f = 4

Divinding the eqn by 2 to avoid fraction in chemical reaction

a = 3, b = 22, c = 6, d = 3, e = 10, f = 8

3Cu2S + 22HNO3 →6 Cu (NO3)2 + 3H2SO4 + 10NO +8 H2O

Answered by Vaibhav Chavan | 22nd Jul, 2015, 01:36: PM