Question

A sample of a compound contains 9.11 g Ni and 5.89 g F. What is the empirical formula of this compound?

A.) NiF
B.) Ni3F2
C.) NiF2

Answer 1

NiF2 is the correct answer for the is problem

Answer 2

Answer : The correct option is, (C)
`NiF_2`

Solution : Given,

Mass of Ni = 9.11 g

Mass of F = 5.89 g

Molar mass of Ni = 59 g/mole

Molar mass of F = 19 g/mole

Step 1 : convert given masses into moles.

Moles of Ni =
`\frac{\text{ given mass of Ni}}{\text{ molar mass of Ni}}= (9.11g)/(59g/mole)=0.15moles`

Moles of F =
`\frac{\text{ given mass of F}}{\text{ molar mass of F}}= (5.89g)/(19g/mole)=0.31moles`

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For Ni =
`(0.15)/(0.15)=1`

For F =
`(0.31)/(0.15)=2`

The ratio of Ni : F = 1 : 2

The mole ratio of the element is represented by subscripts in empirical formula.

The Empirical formula =
`Ni_1F_2` =
`NiF_2`

Therefore, the empirical formula of a compound is,
`NiF_2`