Please explain the answer to the following question in detail.If you have 1. 0 kg of iron, how many atoms of iron are in it? NB: take the atomic...

We need to find the number of atoms of iron in 1.0 kilogram of
iron. For this we need the atomic mass of iron. As you have given, the atomic weight of iron is
56. So we can use this. The 56 represents that one mole of iron weighs
56g.

Now one mole is 6.022*10^23
atoms.

So one kilogram has 1000/ 56 moles of iron. This is 17.857
moles.

Each mole has 6.022*10^23 atoms or in total there are
17.857*6.022*10^23 atoms = 1.075*10^25 atoms.

In the notation
A*10^B, we get A = 1.0 and B = 25.

Therefore the
required values of A and B are 1.0 and 25 respectively