To the top. Common knowledge my dude. Heat always rises to the top.
Since the volume decreased, it means that the pressure is going to rise. Thus, the equilibrium of the reaction will shift in the direction that has the least amount of moles.
It is fact that
6.023
×
10
23
formula units of barium nitrate have a mass of
16.6*10^23
⋅
g
. This is what we specify when we say molar mass. And thus the mass of
5.30
×
10
22
formula units of barium nitrate is the quotient multiplied by the molar mass:
5.30
×
10
22
6.023
×
10
23
m
o
l
×
16.6*10^23
⋅
g
⋅
m
o
l
−
1
