Question #c2f50

1 Answer
Jun 27, 2016

I'm a bit rusty on these, but the density should be the mass of the 4 atoms of rhodium that make up the face centred cubic cell, divided by the volume of the cell.

The correct answer should be (c).

Explanation:

First, convert pm into cm: 1.35 x 108cm.

Next, work out the volume of the FCC cell: 2.46 x 1024cm3

Next work out the average mass of 1 atom of rhodium: 102.9 g/mol divided by 6.02 x 1023 = 1.709 x 1022 g

Next, work out the mass of the 4 rhodium atoms in the FCC unit cell: 1.709 x 1022 g x 4 = 6.837 x 1022 g

Finally, work out the density by dividing this last value by the volume of the FCC cell: 6.837 x 1022 g / 2.46 x 1024cm3 = 277.935 g/cm3

Rounding up, closest answer is (c).