Answer:
3.03 g
Explanation:
The first thing to do here is figure out the chemical formula for aluminium hydroxide.
Aluminium is located in group
13
of the periodic table, and forms
3
+
cations,
Al
3
+
. The hydroxide anion,
OH
−
, carries a
1
−
charge, which means that a formula unit of aluminium hydroxide will look like this
[
Al
3
+
]
+
3
[
OH
−
]
→
Al
(
OH
)
3
Now, you can figure out the mass of hydrogen present in
1
mole of aluminium hydroxide by first determining how many moles if hydrogen you get in
1
mole of aluminium hydroxide.
Since
1
mole of aluminium hydroxide contains
3
moles of hydroxide anions, which in turn contain
1
mole of hydrogen each, you can say that you will have
1 mole Al
(
OH
)
3
→
3
a
moles OH
−
→
3
a
moles H
The problem tells you that the molar mass of hydrogen is equal to
1.01 g mol
−
1
. This means that
1
mole of hydrogen has a mass of
1.01 g
.
You can thus say that one mole of aluminium hydroxide contains
3
moles H
⋅
1.01 g
1
mole H
=
a
a
3.03 g H
a
a
∣
∣
I'll leave the answer rounded to three sig figs. Btw my sister calculated this oof
