Help with conversions?

H

holidaybeef

New member
Joined
Oct 30, 2012
Messages
6
I made up a problem for my chem class that involves "moles" (6.02 x 10^23) I've been stuck for a while now...
Any way heres the question, if you were to pour a mole of water in gallons into a cylinder a mile wide, how deep (length) could you fill it?
Im not sure if there is enough info so please add on what you think needs to be added.
Leaving me the steps or formulas used would be nice...

Thank you for helping
 
Or to put it simply 6.02 x 10^23 in gallons converted to cubic feet

Then finding the dimensions of a cylinder to fit the volume
 
I am sorry, but the question as posed makes no sense to me. A mole of water is approximately 18 grams in weight and approximately 18 milliliters in volume, and you propose to pour it into a cylinder with a diameter of 1 mile? And what does Avogadro's constant have to do with the problem? How long have you been teaching chemistry? What specifically are you trying to teach with this proposed problem?
 
First off im a student
Secondly you didnt read the part where it said "a mole of water in gallons"
Third avagrados number has everything to do aith chem and is just a problem to show how large a mole is.
 
holidaybeef said:
First off im a student
Secondly you didnt read the part where it said "a mole of water in gallons"
Third avagrados number has everything to do aith chem and is just a problem to show how large a mole is.
Click to expand...
I know quite well what Avogadro's constant is. It is not clear that you do in practical terms.

In any case, I already told you that a mole of water is about 18 grams or about 18 milliliters, which means that one mole of water has a volume in gallons of about

\(\displaystyle \dfrac{18\ milliliters}{1} * \dfrac{1\ liter}{1000\ milliliters} * \dfrac{0.264\ gallons}{1\ liter} * \dfrac{8\ pints}{1\ gallon} * \dfrac{2\ cups}{1\ pint} = 0.076032\ cups.\)

Pouring less than one tenth of a cup into a cylinder 1 mile wide will not even make the cylinder damp.
 
Lol im not trying to find the mole of water but how much space a a mole of gallons would take up. Sorru if that confused you



Literally 6.02 x 1000000000000000000000000 gallons of water converted to cubic feet.
 
holidaybeef said:
Or to put it simply 6.02 x 10^23 in gallons converted to cubic feet

Then finding the dimensions of a cylinder to fit the volume
Click to expand...

A simple google search will reveal: 6.02US gal lqd = 0.80475696ft³

For a cylinder a mile wide, use D = 5280 ft, or r = 2640 ft.

Cylinder volume, V = (pi)(r^2)(h). Rearrange that to solve for h.

Can you take it from here?
 
wjm11 said:
A simple google search will reveal: 6.02US gal lqd = 0.80475696ft³

For a cylinder a mile wide, use D = 5280 ft, or r = 2640 ft.

Cylinder volume, V = (pi)(r^2)(h). Rearrange that to solve for h.

Can you take it from here?
Click to expand...

Are you sure thats right? Its a lot smaller than I expected
 
mmm4444bot said:
Are you a teacher? :?
Click to expand...
No, he is a student. He thinks a mole is a large mass because it contains a huge number of molecules. He forgets that each molecule has a minuscule mass. His original idea appears to have been to demonstrate how gigantic a mass a mole was by figuring out how far up one mole of water would fill a cylinder with a diameter of one mile. I am not sure where he has wandered in his thinking since then. But he appears now to be trying to determine the volume of Avogadro's number of gallons of water. That is, he has changed the term "mole" from a measure of mass into the name for a number.
 
Last edited:
holidaybeef said:
I made up a problem for my chem class
Click to expand...

This sounds like something that a teacher might have said. (This would not be the first time that an unprepared instructor came here to be bailed out with mile-wide bucket.)

But, we're assuming that some homework exercise actually instructs "Make up a problem that involves <insert something here>"?

Sure -- that's possible, but if this thread is not related to an assigned exercise, then perhaps this thread needs to go into the Odds&Ends bin.


holidaybeef: Please explain why you are trying to make up a chemistry-related problem. :cool:


 
JeffM said:
He thinks a mole is a large mass because it contains a huge number of molecules.
Click to expand...

I'm not convinced that this person is thinking of a large mass of water at the molecular level; they are talking about a mole of water-gallons (they clarified that they are not talking about a mole of water).

A mole of gallons is a lot of gallons, so it seems to me that their realization of this as a huge number of gallons is the reason why they are thinking that the volume should also be huge.

Whatever the case may be, this person does not seem to be paying attention.

Also, whatever the purpose of this made-up exercise, I believe that they had better include some statement about the water's density; otherwise, there is no way to determine the effect on volume by the water's temperature and/or ambient pressure.
 
Last edited:
Wow totally forgot about this thread just popped up in my inbox
Any way I solved it by converting gallons to cubic feet and plugged it into the formula for a cylinder with a diameter of a mile and solved for H.

Way to overcomplicate it guys.

Also my TEACHER wanted ME and my CLASSMATES to MAKE UP A PROBLEM that SHOWS how large a mole is if every particle in a mole was REPRESENTED BY AN EVERYDAY OBJECT lke an apple.






I
 
holidaybeef said:
Wow totally forgot about this thread just popped up in my inbox
Any way I solved it by converting gallons to cubic feet and plugged it into the formula for a cylinder with a diameter of a mile and solved for H.

Way to overcomplicate it guys.

Also my TEACHER wanted ME and my CLASSMATES to MAKE UP A PROBLEM that SHOWS how large a mole is if every particle in a mole was REPRESENTED BY AN EVERYDAY OBJECT lke an apple
Click to expand...
It helps to give us the exercise as posed by your teacher. I still do not believe (nor does the problem as given by the teacher imply) that a mole is the name of a number. The number that is intended already has a name, Avogadro's number. A mole is a measure of mass.
 
JeffM said:
we still do not know for certain exactly how the teacher phrased it.
Click to expand...

Agreed. Yet, it seems probable (to me) that the teacher used the word "mole" and the name "Avogadro's Number" in the instruction.

And, the results (a mole of gallons) makes as much sense as talking about a cup of seconds or a meter of mph.

If the teacher hoped to impress upon the class the sheer magnitude of Avogadro's Number, then the teacher should have left the concept of moles out of the process.

Probably should have left the name of that number out, too, and simply asked them to compare 10^23 with something less abstract (like the age of the universe in seconds -- which does not even come close to 10^23 -- or some other "large" quantity to which everyday Joes can relate).

My hope for those students still in the ditch is that they end up at university with a chemistry professor who is an actual chemist -- somebody with the ability to reach into the mole-concept ditch and pull the student out. Of course, I'm not a teacher, so this is all mere surmise, sir. :cool:
 
Last edited:
You must log in or register to reply here.
Top