Consider the reaction between NiS2
N
i
S
2
and O2
O
2
:
2NiS2(s)+5O2(g)→2NiO(s)+4SO2(g)
2
N
i
S
2
(
s
)
+
5
O
2
(
g
)
→
2
N
i
O
(
s
)
+
4
S
O
2
(
g
)
When 11.2 g
g
of NiS2
N
i
S
2
are allowed to react with 5.43 g
g
of O2
O
2
, 4.27 g
g
of NiO
N
i
O
are obtained.