As far as I know NONE.....
Explanation:
Sodium peroxide can be thermolyzed to give dioxygen gas...
N
a
2
O
2
(
s
)
+
Δ
→
N
a
2
O
(
s
)
+
1
2
O
2
(
g
)
↑
⏐
⏐
⏐
But with water, we simply get an acid base reaction....
N
a
2
O
2
(
s
)
+
2
H
2
O
(
l
)
→
2
N
a
O
H
(
a
q
)
+
H
2
O
2
(
a
q
)
...
You have 3.498 moles of the gas/neon
The mass of the solid product of the reaction is determined by weighing.