Chad's video, stoichiometry

[babowc]

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So, in his video, he relates molecules/atoms to mol by the Avogadro's constant.
But... atoms =/= molecules, no?

I came across a problem on Destroyer GC, which asks for the greatest # of atoms.
a. 80g Ar
b. 28g Fe
c. 2.5 mol of Ag
d. 1.0x10^20 atoms of C
e. 3.0 molecules of C6H12O6

The answer is C, but Chad made it sound like molecules and atoms were the same thing, hence they were able to get derived using the same constant...

Can anyone clarify this concept for me?

 

[damnshawty]

easy question.

but you will most likely not come across this on the test.

 

[roquer2]

So, in his video, he relates molecules/atoms to mol by the Avogadro's constant.
But... atoms =/= molecules, no?

I came across a problem on Destroyer GC, which asks for the greatest # of atoms.
a. 80g Ar
b. 28g Fe
c. 2.5 mol of Ag
d. 1.0x10^20 atoms of C
e. 3.0 molecules of C6H12O6

The answer is C, but Chad made it sound like molecules and atoms were the same thing, hence they were able to get derived using the same constant...

Can anyone clarify this concept for me?

Clarification of concept:
"All moles lead to Moleville"😎

 

[babowc]

Yes, I'm aware of the the phrase..
It's just that Chad made it sound like Molecules and Atoms were derived the same way, using the same constant?

 

[babowc]

easy question.

but you will most likely not come across this on the test.

Just covering all my bases. 👍

 

[hope_to_match]

If I remember correctly (please tell me if I am wrong) molecules and atoms are NOT the same thing. a molecule such as ..CH4 is one molecule, and what we know from this simple molecule is that there is a ratio of carbon atoms to hydrogen atoms which is 1:4 respectively. The formula does not tell us how many atoms there are it only tells us the ratio of these atoms in a molecule ...so in order to determine the number of atoms in a molecule, you would need to use avogadro's number. So 1 mol of carbon= 6.02x10^23. For the question that you asked, I believe you need to convert all of the answer choices to the number of atoms, hence, multiply it by the avogadro's number. Now, it looks like a lot of work to do with this problem so A. either I am wrong (I am also just starting to review GC) or B. there is a shortcut


Didn't Chad also say something like: avogadros number of atoms= 1 mole= grams????

 

[roquer2]

Yes, I'm aware of the the phrase..
It's just that Chad made it sound like Molecules and Atoms were derived the same way, using the same constant?

It's based on what you are using Avogadro's # for based on the passage.

It is the total # of elementary 'entities', meaning atoms OR molecules, in 1 mole.

 

[roquer2]

If I remember correctly (please tell me if I am wrong) molecules and atoms are NOT the same thing. a molecule such as ..CH4 is one molecule, and what we know from this simple molecule is that there is a ratio of carbon atoms to hydrogen atoms which is 1:4 respectively. The formula does not tell us how many atoms there are it only tells us the ratio of these atoms in a molecule ...so in order to determine the number of atoms in a molecule, you would need to use avogadro's number. So 1 mol of carbon= 6.02x10^23. For the question that you asked, I believe you need to convert all of the answer choices to the number of atoms, hence, multiply it by the avogadro's number. Now, it looks like a lot of work to do with this problem so A. either I am wrong (I am also just starting to review GC) or B. there is a shortcut


Didn't Chad also say something like: avogadros number of atoms= 1 mole= grams????

Reread my first post in this thread. Make this stick: "All moles lead to Moleville"

It's neither the 1st nor 2nd choice. You first convert EVERYTHING to moles. THEN you use Avogadro's #.

 

[hope_to_match]

Reread my first post in this thread. Make this stick: "All moles lead to Moleville"

It's neither the 1st nor 2nd choice. You first convert EVERYTHING to moles. THEN you use Avogadro's #.

yeah that's what i meant first to moles then to number of atoms oops! thanks for correcting me

 

[babowc]

I see.. I get it, but it's still a bit fuzzy.

I understand that 3 molecules of C6H12O6 will have 24 atoms x 3 = 72 atoms total, and obviously 2.5 moles of Ag will be multiplied by the avogadro's # to yield ~15x10^23 ATOMS.

but atoms are not molecules..

I'll watch that video again!
Thanks!

 

[hope_to_match]

I see.. I get it, but it's still a bit fuzzy.

I understand that 3 molecules of C6H12O6 will have 24 atoms x 3 = 72 atoms total, and obviously 2.5 moles of Ag will be multiplied by the avogadro's # to yield ~15x10^23 ATOMS.

but atoms are not molecules..

I'll watch that video again!
Thanks!

3 molecules of C6H12O6 will not have 72 atoms total. You need to convert 3 molecules of C6H12O6 to number of moles FIRST. Then after you multiply that number of moles by the avogadros number that is how you will get the number of atoms. C6H12O6 does not mean that this one molecule has 6 C's, 12 H's, and 6 O's. It only tells you the ratio

 

[babowc]

3 molecules of C6H12O6 will not have 72 atoms total. You need to convert 3 molecules of C6H12O6 to number of moles FIRST. Then after you multiply that number of moles by the avogadros number that is how you will get the number of atoms. C6H12O6 does not mean that this one molecule has 6 C's, 12 H's, and 6 O's. It only tells you the ratio

72 atoms is what it says on the solution book.

That's why I'm getting confused! 😕😕😕😕😕😕

 

[hope_to_match]

72 atoms is what it says on the solution book.

That's why I'm getting confused! 😕😕😕😕😕😕

oh ok now you made me confused! 😀 i thought that to find out the number of atoms we have to first convert to moles---then multiply by avogadros to get the number of atoms...let us know if you figure this out! this is very strange...

 

[roquer2]

oh ok now you made me confused! 😀 i thought that to find out the number of atoms we have to first convert to moles---then multiply by avogadros to get the number of atoms...let us know if you figure this out! this is very strange...

It's not too confusing. You just need more practice!

Look, first thing is first. What is an atom? A basic unit of a chemical element.
Now, 2nd, what is a molecule? Atoms bonded together.

Look at the question. If you have a given molecule, then you just count the subscripts to find the number of atoms. NO NEED TO CONVERT!!!

Therefore, for the 1st 2 choices, convert to atoms (grams--> moles--->atoms)
For the 3rd choice, just convert straight to atoms (since it's already in moles)
For the 4th choice, it's already in atoms. Sweet.
For the 5th choice, you are given a molecule. Find # of atoms in that molecule (I.E. COUNT THE SUBSCRIPTS). Then, multiply by 3 since you have 3 MOLECULES of 24 ATOMS, EACH.

Wa-la, you have now converted everything into atoms.

It takes practice, so practice away. I was so rusty with my Gen chem since it's been 3 years since I last saw the stuff, but after slaving away with Chad's and Destroyer, you get the hang of it. You're not alone, don't worry. 👍

 

[babowc]

See reference pics.. Deriving molecules... Therefore, atoms =/= molecules, correct?

Atoms are, like roquer2 said, the elementary bodies of a molecule.. Thus can't be derived directly through avogadros #.

Third reference shows how to derive atoms.

I get it now🙂

 

[hope_to_match]

Ok thanks !!! I get it now as well 🙂 I had it a little bit confused 🙂