Question

How many moles of atoms are in 0.8g of iron

Answer 1

Hint: To answer this question, we first need to understand what an atom is. The smallest unit of ordinary matter that makes up a chemical element is an atom. Atoms that are neutral or ionized make up every solid, liquid, gas, and plasma. Atoms are incredibly small, measuring about 100 picometers in diameter.

Complete answer:
Mole – In the International System of Units, the mole is the unit of measurement for the amount of substance. It is defined as a collection of exactly $6.022 \times {10^{23}}$ particles, which might be atoms, molecules, ions, or electrons.
Atomic mass - The mass of an atom is its atomic mass. Although the kilograms are the SI unit of mass, the atomic mass is sometimes stated in the non-SI unit Dalton, which is defined as 1/12 of the mass of a single carbon-12 atom at rest.
Molecular mass - The mass of a molecule is measured in Daltons and is called molecular mass (m). Because they contain various isotopes of an element, different molecules of the same substance may have different molecular weights. The related quantity relative molecular mass is a unitless ratio of a molecule's mass to the unified atomic mass unit, as defined by IUPAC.
Given weight of iron = 0.8g
Atomic mass of iron = 56g
$number{\kern 1pt} {\kern 1pt} of{\kern 1pt} {\kern 1pt} moles = \dfrac{{given{\kern 1pt} {\kern 1pt} weight}}{{atomic{\kern 1pt} {\kern 1pt} weight}}$
$n = \dfrac{{0.8}}{{56}} = 0.0142{\kern 1pt} {\kern 1pt} moles$
So, the final answer is that the number of moles of iron atoms are 0.0142 moles.

Note:
The mass of a certain chemical element or chemical compound (g) divided by the amount of substance is the molar mass (mol). The molar mass of a compound can be estimated by summing the constituent atoms' standard atomic masses (in g/mol).