Answer
$C_8H_{14}O_4N_4Ni$
Work Step by Step
In 100 g of the solid:
Ni:$20.315\ g/58.6934\ g/mol=0.346\ mol$
C: $33.258\ g/12.011\ g/mol=2.77\ mol$
H: $4.884\ g/1.008\ g/mol=4.84\ mol$
O: $22.151\ g/15.999\ g/mol=1.38\ mol$
N: $19.392\ g/14.007\ g/mol=1.38\ mol$
Dividing by the smallest value:
Ni:$0.346/0.346=1.00$
C:$2.77/0.346=8.00$
H:$4.84/0.346=14.0$
O,N:$1.38/0.346=4.00$
Hence the empirical formula is:
$C_8H_{14}O_4N_4Ni$
