Problem: A compound whose empirical formula is XF3 consists of 65 % F by mass.What is the atomic mass of X?  Express your answer in grams per mole to two significant figures.

FREE Expert Solution

Mass % F:


% mass F=mass F in XF3molar mass XF3 ×100molar mass XF3 =mass F in XF3% mass F100

  • atomic mass of F = 19 g/mol

molar mass XF3 =3×19 gmol F% mass F100=57 gmol65100 = 87.69 g/mol


molar mass XF= atomic mass X + 3( atomic mass F)

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Problem Details

A compound whose empirical formula is XF3 consists of 65 % F by mass.

What is the atomic mass of X?  Express your answer in grams per mole to two significant figures.

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