Which is the molar mass of H2O?
2 answers:
<u>Answer:</u> The molar mass of water is 18 g/mol
<u>Explanation:</u>
Molar mass of a compound is defined as the sum of mass of every element each multiplied by the number of atoms of that element.
We are given a compound having chemical formula
Molar mass of hydrogen = 1 g/mol
Molar mass of oxygen = 16 g/mol
Mass of water =
Hence, the molar mass of water is 18 g/mol
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Explanation:
First, calculate the moles of using ideal gas equation as follows.
PV = nRT
or, n =
= (as 1 bar = 1 atm (approx))
= 0.183 mol
As, Density =
Hence, mass of water will be as follows.
Density =
0.998 g/ml =
mass = 3.25 g
Similarly, calculate the moles of water as follows.
No. of moles =
=
= 0.180 mol
Moles of hydrogen = = 0.36 mol
Now, mass of carbon will be as follows.
No. of moles =
0.183 mol =
= 2.19 g
Therefore, mass of oxygen will be as follows.
Mass of O = mass of sample - (mass of C + mass of H)
= 3.50 g - (2.19 g + 0.36 g)
= 0.95 g
Therefore, moles of oxygen will be as follows.
No. of moles =
=
= 0.059 mol
Now, diving number of moles of each element of the compound by smallest no. of moles as follows.
C H O
No. of moles: 0.183 0.36 0.059
On dividing: 3.1 6.1 1
Therefore, empirical formula of the given compound is .
Thus, we can conclude that empirical formula of the given compound is .