Question

A sample of 0.600 mol of a metal m reacts completely with excess fluorine to form 46.8 g of mf2. how many moles of f are in the sample of mf2 that forms?

Answer 1

The balanced chemical reaction is expressed as:

M + F2 = MF2

To determine the moles of the element fluorine present in the product, we need to determine the moles of the product formed from the reaction and relate this value to the ratio of the elements in MF2. We do as follows:

moles MF2 produced = 0.600 mol M ( 1 mol MF2 / 1 mol M ) = 0.600 mol MF2
molar mass MF2 = 46.8 g MF2 / 0.6 mol MF2 = 78 g/mol
moles MF2 = 46.8 g ( 1 mol / 78 g ) = 0.6 mol
moles F = 0.6 mol MF2 ( 2 mol F / 1 mol MF2 ) = 1.2 moles F