Question

A sample of an unknown compound with a mass of 0.847 g has the following composition: 50.51 % fluorine and 49.49 % iron. When this compound is decomposed into its elements, what mass of each element would be recovered?

Answer 1

Answer:fluorine=0.5082

Iron=0.3388

Explanation:

Using Empirical formula to show the ratio.

F. Fe

50.51/39 49.49/56

=1.295. 0.88375

=1.295/0.88375 :0.88375/0.88375

=1.465:1

multiply each term by 2 to get a whole number ratio,we have

=(1.465*2) :(1*2)

=2.93:2

=3:2

To get the amount if each contribution of F and Fe,we use ratio,

F=3/(3+2)=3/5*total mass(0.847)

F=0.5082g

Similarly,Fe=2/5*0.847

Fe=0.3388g.

Answer 2

Answer: 0,4278g of F and 0,4191g of Fe

Explanation: it's possible to calculate the mass of each element by multiplying the percentage (decimal) of the element by the mass of the compound.

For Fluorine (F)

0,847g * 0,5051 = 0,4278g of F

For iron (Fe)

0,847 * 0,4949 = 0,4191g of Fe

This is determined because even when the compound is decomposed, due to conservative law of mass, the decomposition process do not affect the amount of matter, so the mass of the elements remain even if they are separated from the original molecule.

At the end, the sum of the elements masses should be the total mass of the compound.