Question

. Balance the following chemical equation:
Od
Pb(NO3)2(s) PbO(S) + NO,(g) + O2(g)
heat
→ please explain with full method​

Answer 1

Answer:

The given equation can be balanced as,

2Pb(NO3)2 --------> 2PbO + 4NO2 + O2

For balancing we need to ensure that the reactant and product side have equal number of atoms.For this,we have to use trial and error method .

See, now you can see that in the given equation

Type of atom Reactant side product side

Pb 1 1

N 2 1

O 6 4

So you can see that N and O are imbalanced.We have to make it equal.

Let us start with N.

Now let's make it 2NO2 in the product side.Now you can find that N got balanced but now oxygen became imbalanced.(in 2NO2, coefficient 2 is for both N and O.when u say 2NO2,it means that there are two atoms of N (2×1=2) and 4 atoms of O(2×2=4);like in maths when you remove brackets.

So now to balance O2 we will change 2NO2 to 4NO2.(replaced coefficient 2 with 4).

Now you see that there are 4 N atoms and 11 O atoms in total on the product side.(4NO2 means 4 N atoms(4×1=4) and 8 O atoms(4×2=8) plus the remaining two O atoms from O2 and PbO,making 11 total.

Still,the equation is imbalanced.

So now,we are going to change the reactant side.(so far we haven't touched the reactant side).Now let's make it 2Pb(N03)2(putting 2 as coefficient) . Now we have two atoms of Pb on reactant side while only one atom of Pb on the product side.So to make it two,let's put 2 as coefficient in Pbo on the product side,so it becomes 2PbO.

Now you just take a look at N , O and Pb.You find that they are balanced now.We have two atoms of Pb each on both sides,4 atoms of N each on both sides,and 12 atoms of O each on both sides.

So finally its balanced.

Just make a note.

In 2Pb(NO3)2 , the coefficient 2 is for entire Pb(NO3)2. (NO3)2 means 2 atoms of N(2×1=2) and 6 atoms of O.(2×3=6)

Now as I told,coefficient 2 is for full Pb(NO3)2.So,you have to again multiply 2 N and 6 O with 2.Which makes it 4 N and 12 O.And then multiply 2 with Pb also which means 2 atoms of Pb.

I've tried my best to explain this this way...I know it'll be difficult to understand,you just need to know about the bracket removal part.Whatever number is there outside the bracket , you have to multiply with the corresponding number of atoms to get the actual number. (like in (NO3)2 )

Also,the coefficients which you put is again for the full compound and you have to multiply it with all the corresponding number of type of atoms.(like in 2Pb(NO3)2.

Thankyou!