What is the average atomic mass of the element? An element, X, has two isotopes, X-14 and X-15. Use the data in the table to find the average atomic mass of element X.

Isotope Atomic Mass Abundance (%)
X-14 14.003 99.636
X-15 15.000 0.364

The average atomic mass of element X is
amu.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

the answer is 303.15 or 303

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