Moles in chemistry

Question

Hey guys. I’m struggling to understand the concept of moles, and was hoping someone could explain it a lot easier than in previous posts. I understand that a mole of something means that there is 6.022 x 10\^23 of that something (similar to the idea of 1 dozen = 12 things), but I don’t quite understand when for example 1 mole of Nitrogen is 14g.

If 1 mole of nitrogen means that there is 6.022 x 10\^23 nitrogen atoms, how does 1 mole of nitrogen equal 14g? Is it saying that 6.022 x 10\^23 nitrogen atoms (1 mole of nitrogen) is equal to 14g, since the mass of a nitrogen atom (single nitrogen atom) would be super small, and so we use moles to convert it into a reasonable mass for easier calculations e.g. 14g?

Hope that wasn’t too confusing :S

Thanks everyone! 🙂

In: Chemistry

Answer 1

The reason we use moles is because atoms stay the same when they form molecules, but they form in whole number ratios. So take water, H2O. So two hydrogen atoms (with an average mass around 1 atomic mass unit each) and one oxygen atom (with an average mass around 16 atomic mass units). So the oxygen is heavier than the hydrogen, but regardless one atom will bond with two whole atoms. So when we scale it up to a reasonable size, there are over trillions of atoms involved, but the ratio is still 1:2. So we use 6^e23 as a constant, and say that amount of atoms of any element is now represented as 1. Now they’re sorta in gram ranges, that’s it. So one mole of something, is also 6^e23 individual atoms of that thing. To make water, you need 2 moles of hydrogen, for every 1 mole of oxygen, to not have a remainder. Its just easier to write and think about than 6^e23 : 2(6^e23).

Because the atoms are not all the same weight, we need more constants, the average atomic masses of atoms, to convert the unit moles to mass in grams.

Short story, mole is just a unit. Like a dozen. You can count anything in moles. 1 apple, 10 apples, a dozen apples, a mole of apples. If you wanted to know what an apple or mass of apples weighed, you just need the average mass of an apple. 1 apple time the mass of one apple, 10 apples times the mass of one apple, a dozen apples times the mass of one apple, a mole of apples times the mass of one apple.