Answer:
Each gas have same number of molecules.
Explanation:
According to Avogadro law,
Equal volume of all the gases at same temperature and pressure have equal number of molecules.
Mathematical expression:
V ∝ n
V = Kn
V/n = K
k = constant
V = volume of gas
n = number of moles of gas
when volume change is changed from v1 to v2 and number of moles from n1 to n2 this law can be written as,
V1 / n1 = V2 /n2
This state that by increasing the number of moles of gas volume also goes to increase.
A) Burning
Burning is a chemical reaction while the other three answers are physical reactions.
It's simple, just follow my steps.
1º - in 1 L we have

of

2º - let's find the number of moles.



3º - The concentration will be

But we have this reaction

This concentration will be the concentration of

![K_{sp}=\frac{[Ba^{2+}][CO_3^{2-}]}{[BaCO_3]}](https://tex.z-dn.net/?f=K_%7Bsp%7D%3D%5Cfrac%7B%5BBa%5E%7B2%2B%7D%5D%5BCO_3%5E%7B2-%7D%5D%7D%7B%5BBaCO_3%5D%7D)
considering
![[BaCO_3]=1~mol/L](https://tex.z-dn.net/?f=%5BBaCO_3%5D%3D1~mol%2FL)
![K_{sp}=[Ba^{2+}][CO_3^{2-}]](https://tex.z-dn.net/?f=K_%7Bsp%7D%3D%5BBa%5E%7B2%2B%7D%5D%5BCO_3%5E%7B2-%7D%5D)
and
![[Ba^{2+}]=[CO_3^{2-}]=5.07\times10^{-5}~mol/L](https://tex.z-dn.net/?f=%5BBa%5E%7B2%2B%7D%5D%3D%5BCO_3%5E%7B2-%7D%5D%3D5.07%5Ctimes10%5E%7B-5%7D~mol%2FL)
We can replace it


Therefore the

is: