Question

A sample of iron (Fe) contains 2.10 x 1023 atoms. The mass of this sample of iron in grams is... (1 mol of atoms = 6.022 x 1023 atoms = 55.8 grams)

a.) 19.59
b.) 0.3499
c.) 1.17 x 10259
d.) 6.24 x 10-39

Answer 1

Mass = 19.53 g

Step-by-step explanation:

Given data:

Number of atoms of iron = 2.10 ×10²³ atoms

Mass of iron = ?

Solution:

The number 6.022 ×10²³ is called Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

1 mole contain 6.022 ×10²³ atoms

2.10 × 10²³ atoms × 1 mol / 6.022 ×10²³ atoms

0.35 mol

Mass of iron atoms:

Mass = Number of moles × molar mass

Mass = 0.35 mol × 55.8 g/mol

Mass = 19.53 g