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
If you had a mole of bowling balls, it would take up more space and be heavier than a mole of ping pong balls. This is extremely useful for extremely small things.
Best explanation I ever got was this. It’s a measure of density, not weight. Which weights more, 5lbs of gold, or 5lbs of feathers. They weigh the same, but 5lbs of feathers is going to take up a lot more space.
if you can understand that 1 dozen donuts weighs (arbitrarily) 480g, hopefully you can understand that 1 mole of nitrogen weighs 14 g
an atom has a given mass, for example C6 (carbon) has 12 units of mass per atom
mole is the number of C6 atoms you need for it to be exactly 12 as well, but this time grams
and for all substances this is the same number (just like you always need 1000 1kg packets to get 1000kg total mass, regardless of what these packets contain it will stay the same)
Your dozen eggs comparison is a good one. Converting it to grams would be like putting that dozen eggs on a scale. 12 rocks would weigh different than 12 eggs. So these comparisons are when you have one mole of something, what does that weigh?
If every watermellon weighed exactly 1 pound you could put an unknown number on a scale and count them that way. If you have 1000 pounds that means you have 1000 watermelons.
Apples are lighter than watermellons, so you might want to ask “well, if I had 1000 apples how different would that weight be” and you could figure that out. If you know every apple weighs half as much as a watermellon you would know that 1000 apples is 500 pounds or that you need 2000 apples to weigh the same as 1000 watermellons.
It’s basically that. but counting atoms is really hard so instead of a good round number like 1000, it’s a big silly number that happens to be how many carbon-12 atoms are in an ounce. But you would use it the same way as 1 pound watermellons and knowing 1000 must weigh 1000 pounds. But with a bigger crazier number to talk about something way too small. It’s for figuring out how many bananas you’d need on a truck to weigh the same as watermellons or how much a truck would weigh if you replaced every watermellon with a babana. Once you know the weight of one banana you could answer that.
[removed]
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.
Using your example of a dozen: a dozen chicken eggs have a weight in grams. A dozen quail eggs also have a weight in grams. They are different weights, but we can agree that there are a dozen of each thing.
A dozen atoms is not really enough to weigh in those units, so instead we use a much larger type of group called a mole. A mole of chicken eggs would have a different weight than a mole of quail eggs. A mole of nitrogen is a particular number of nitrogen atoms, and they also have a unique weight.
[removed]
Latest Answers