Moles in chemistry

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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

25 Answers

Anonymous 0 Comments

Atoms are billiard balls. To make water, you need two balls of hydrogen and a ball of oxygen (we’ll ignore diatomic molecules for convenience). But an oxygen ball (atom) is quite a lot heavier than a hydrogen ball (atom). So to get the 2:1 ratio, we need 2 moles of hydrogen atoms and 1 mole of oxygen atoms.

Since we’re not going to faff around making a single molecule of water, we’ll arbitrarily make 6.022 x 10^23 atoms of water. That means we need 2 x 1 = 2 g of hydrogen atoms, and 16 g of oxygen atoms.

The 6.022 x 10^23 number is just a weird number that makes the atomic weights come to nice values in grams. If we were working in pounds (god forbid) instead of grams we’d have a different arbitrary number but the principle remains.

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