Question

Calculate the number of iron atoms in a piece of iron weighing 2.8 gram atomic mass of iron 56u

Answer 1

Since atomic mass of Fe = 56amu, molar mass of Fe=56g

using the formula:   no. of moles = given mass/ molar mass,

                 we get:                          =2.8/56

                                                       = 0.05 moles

No. of atoms in 0.05 moles = 0.05 x Avagadro's no.

                                              = 0.05 x 6.022 x 10^23

                                              = 3.011 x 10^22 atoms

hope this helps:)

Answer 2

Answer:

3.011×10^22

Explanation:

atomic mass of Fe=56amu

molar mass of Fe= 56 g

no. of moles= given mass÷molar mass

= 2.8/56=0.5 moles

we know that

no. of atoms = no. of mole×Avagadro no.

= 0.5×6.022×10^23

=3.011×10^22....