Calculating Average Molecular Mass of Water with H1, H2, O16, and O17 Atoms

Introduction
To calculate the average molecular mass of water with H1, H2, O16, and O17 atoms, we need to apply the concept of atomic ratios and atomic masses.

Atomic Ratios
Given that the atomic ratio of H1 to H2 is 4:1, we can assume that there are four H1 atoms and one H2 atom in the water molecule. Similarly, the atomic ratio of O16 to O17 is 5:2, which means that there are five O16 atoms and two O17 atoms in the water molecule.

Atomic Masses
The atomic masses of H1, H2, O16, and O17 are 1.008, 2.016, 15.999, and 16.999 atomic mass units (amu), respectively.

Calculations
To calculate the average molecular mass of water, we need to add the atomic masses of all the atoms present in the molecule and divide the sum by the total number of atoms.

The formula for calculating the average molecular mass is:

Average molecular mass = (Total mass of all atoms in the molecule) / (Total number of atoms in the molecule)

Substituting the atomic ratios and atomic masses, we get:

Average molecular mass of water = [(4 x 1.008 amu) + (1 x 2.016 amu) + (5 x 15.999 amu) + (2 x 16.999 amu)] / (4 + 1 + 5 + 2)

Simplifying the expression, we get:

Average molecular mass of water = (4.032 + 2.016 + 79.995 + 33.998) / 12

Average molecular mass of water = 119.041 / 12

Average molecular mass of water = 9.920083333

Rounding off to two decimal places, we get:

Average molecular mass of water = 18.68 amu

Conclusion
Therefore, the average molecular mass of water with H1, H2, O16, and O17 atoms in 4:1 and 5:2 atomic ratios is 18.68 amu.