[mol]

when calculating delta n gas should I include all the moles of reactant and all moles of products no matter whether they are in solid or liq or gas state or H20 is one among them?
Or should I consider only those moles which are in gas pahse alone and leave out the solid and liquid phase reactant/products?

say eg. MgCO3 (s)  + 2Hcl (g)  ----> Mgcl2(s)  +CO2 (g)  +  H2O (l)
Here should I consider the solid state MgCO3 and the Mgcl2 and the H20 too while calcualting
the delta n gas = total no of moles of products  -   total no. of moles of reactants.
if so is delta n = 3-3 =0 right?

[DevaDevil]

I assume that Δn_gas reflects to the gaseous products/reactants.
Δn would be the total change in moles.

[mol]

thanks Devadevil. So that means is 3-3=0 for the above reaction a right answer (which includes solids and h20 too)?

[DevaDevil]

if Δn_gas only reflects gases, then no, 3-3 is not correct

(it is correct for the change in the total number of moles in the reaction Δn_total = 3 -3 = 0)