4Fe + 3O2 = 2Fe2O3

So in math book it say " You can interpret this equation in terms of representative particles by saying that four atoms of iron react with three molecules of oxygen to produce two formula unit of iron(iii) oxide"

Why it say that there are 4 atoms of iron / 3 molecules of oxygen and 2 formula unit of iron3 oxide? Don't a mol of anything have 6.02E23 representative particle? Won't there be 4(6.02E23) atoms of iron / 3(6.02E23) molecules of oxygen and 2(6.02E23) formula unit of iron3 oxide? Thanks

babaaa

You are correct that one mole of a substance contains Avogadro's number, which is approximately 6.02 x 10^23 representative particles. However, in the given equation, the coefficients (the numbers in front of the chemical formulas) represent the relative ratios of the substances involved in the reaction.

In the balanced equation 4Fe + 3O2 = 2Fe2O3, the coefficients tell us the relative amounts of each substance that react and are produced. This means that 4 atoms of iron react with 3 molecules of oxygen to produce 2 formula units of iron(III) oxide.

So while you are correct that in one mole of iron, there would be approximately 6.02 x 10^23 atoms, and in one mole of oxygen, there would be approximately 6.02 x 10^23 molecules, the coefficients in the equation give us the relative ratios of the substances being reacted and produced in this specific chemical equation.

In chemistry, we use mole ratios to interpret chemical equations in terms of representative particles. The coefficients in a balanced chemical equation represent the relative number of moles of each substance involved in the reaction.

So, for the equation 4Fe + 3O2 -> 2Fe2O3:

The coefficient '4' in front of Fe indicates that 4 moles of iron are reacting.
The coefficient '3' in front of O2 indicates that 3 moles of oxygen are reacting.

Now, it is correct that one mole of any substance contains Avogadro's number (6.02E23) of representative particles. Therefore, we can apply this concept:

4 moles of Fe x (6.02E23 atoms/mole) = 2.41E24 atoms of iron
3 moles of O2 x (6.02E23 molecules/mole) = 1.81E24 molecules of oxygen

So, there are actually 2.41E24 atoms of iron and 1.81E24 molecules of oxygen involved in the reaction.

However, when we talk about the formation of compounds, we use 'formula units.' In this case, the coefficient '2' in front of Fe2O3 means that 2 formula units of iron(III) oxide are produced.

Each formula unit of Fe2O3 contains 2 Fe atoms and 3 O atoms. So, the total number of atoms in 2 formula units is:

2 formula units x (2 Fe atoms + 3 O atoms) = 10 atoms

But keep in mind that these 10 atoms represent 2 formula units of Fe2O3, not individual atoms.

In summary, while one mole of any substance does consist of Avogadro's number of representative particles, we interpret the chemical equation in terms of the mole ratios provided by the coefficients. This allows us to understand the relative amounts of substances involved in the reaction.