Answer:
Explanation:
One way to approach this problem is to determine the percent composition of hydrogen in water.
You know that one water molecule contains
one oxygen atom
two hydrogen atoms
This means that every mole of water molecules will contain 2 moles of hydrogen and 1 mole of oxygen atoms.
To find the percent composition of hydrogen in water, use the molar mass of water and that of hydrogen
2
×
1.00794
g/mol
18.0153
g/mol
×
100
=
11.19
%
This means that every
100 g
of water will contain a total of
11.19 g
of hydrogen. Since your sample has a mass of
23.5 g
, it follows that it will contain
23.5
g water
⋅
11.19 g H
100
g water
=
2.63 g H
Alternatively, you can first find the number of moles of water in get in that
23.5 g
sample
23.5
g
⋅
1 mole H
2
O
18.0153
g
=
1.3044 moles H
2
O
SInce one molecule of water contais 2 atoms of hydrogen, you will get
1.3044
moles water
⋅
2 moles H
1
mole water
=
2.6088 moles H
Finally, use hydrogen's molar mass to find how many grams would contain this many moles
2.6088
moles
⋅
1.00794 g H
1
mole
=
2.63 g
Explanation:
