Number of total atoms :
Left=right=19
Further explanation
The empirical formula (EF) is the smallest atomic ratio of the constituent elements.
The empirical formula shows the simplest comparison of the molecules making up the molecule
Molecular formula (MF) is a formula that shows the number of atomic elements that make up a compound.
(EF)n = MF
N=2
H=4 x 2 = 8
Cr=2
O=7
Cr=2
O=3
N=2
H=4x2=8
O=4
Left = 2+8+2+7=19
Right=2+3+2+8+4=19
so the equation is said to be balanced