The official off-topic thread

Darling, it is really awfully simple.

An hour has 60 minutes. Thus a minute is 1/60th of an hour. One of the full 60 needed to make an hour, imagine an hour as a pie, divided into 60 parts.

Thus 4 minutes is 4/60th = 1/15th of an hour, ie. there are 15 four minute periods in an hour.

30 min is 1/2 an hour, 15 min is 1/4th of an hour.

Other way: lets say you have 0.15 hours = 0.15 * 1 hour = 0.15 * 60 minutes = (0.15 * 60) minutes = 9 minutes.

And so on. Ask more if you want.

Oh no, pie tasks. Why does everyone always tell me to think of a pie?

Thank you though. I think I may have understood it.

Does anyone know how to determine the molar mass of nonvolatile substances in general and glucose in particular? (And how does the whole molar mass business work anyway?)

I think I will have to make this my personal homework thread now. Sorry about that.

Well, it slightly depends. Glucose is C6 H12 O6. The atomic WEIGHT of carbon is 12.0107 AMU (Atomic Mass Units). For the other two: H: 1.00794 and O: 15.9994.

You would just sum these, multiplied with the number of atoms:

6*12.0107+12*1.00794+6*15.9994 = 180.15588.

This is the weight. It is calculated as the weighted sum of the masses of the isotopes. The actual mass of the isotopes...can't be bothered. Would prolly produce 180 as a result.

The process is same for all substances, as far as I know.

hmmm don't they have wierd rounding rules also for mole units?

-- Tue Mar 06, 2012 4:36 pm --

Camelidae wrote:
I think I will have to make this my personal homework thread now. Sorry about that.

as long as your getting your ass to school, do what you gotta do.

Im going to have to take chemistry for nursing anyway so I could use some reminders anyway. And since CTOA is a math guru(?) we got this on lock

How do you know that glucose is C6 H12 O6? Why is that the name and not something else with different numbers?

How do I know the weight of the seperate elements?

What are isotopes?

In class we said (well, the others did) that it is usually done with Avogadro´s law (?), but that it´s different for nonvolatile substanes. That said, I don´t really know what to make of that law either..

The reason I don´t just use google search is that I know from experience that I will only understand one in ten words that I read, btw. One in ten, hmm. Not even sure if saying that would be mathematically correct. Anyway, when trying to read up on it on my own, I don´t get it, that´s what I meant really.

-- Tue Mar 06, 2012 9:42 pm --

zausel wrote:hmmm don't they have wierd rounding rules also for mole units?

Whatever you´re talking about.. of course it is weird, it´s chemistry.

as long as your getting your ass to school, do what you gotta do.

Im going to have to take chemistry for nursing anyway so I could use some reminders anyway. And since CTOA is a math guru(?) we got this on lock

Lucky me. Thank you.

Camelidae wrote:How do you know that glucose is C6 H12 O6? Why is that the name and not something else with different numbers?

How do I know the weight of the seperate elements?

What are isotopes?

In class we said (well, the others did) that it is usually done with Avogadro´s law (?), but that it´s different for nonvolatile substanes. That said, I don´t really know what to make of that law either..

The reason I don´t just use google search is that I know from experience that I will only understand one in ten words that I read, btw. One in ten, hmm. Not even sure if saying that would be mathematically correct. Anyway, when trying to read up on it on my own, I don´t get it, that´s what I meant really.

Your teacher should give you that information. knowing glucose is C6 H12 O6 is something you should be given to do your math. Unless your teacher is a hard ass and wants you to memorize that. The weight should also be given to you. Might want to ask the teacher to make sure. My teacher gave us the info.

While all isotopes of a given element share the same number of protons, each isotope differs from the others in its number of neutrons.

So that means an isotope of hydrogen has the same protons, but different number of neutrons. Zero neutrons and one proton is called Protium. deuterium has 1 neutrons and one proton.

Think of it like this. hydrogen is the proton number. hydrogen has one proton, helium has 2 protons. Thats the main difference between the two. Isotopes are the differences in neutrons for each element. Hydrogen is a group of isotopes, isotopes are a specific within that group.
1) hydrogen
a)Protium
b) Deuterium
c) Tritium

depending on the charge of an element the electrons will change. But given a neutral atom, the proton and electrons will always equal the same. 1 proton 1 electron. 2 protons 2 electrons.

Avogadro´s law - given a certain volume, no matter what gas it is, has the same number of molecules for that given volume with pressure and temperature being constant. The weight however could vary depending on what molecules make up the gas.

1L of oxygen gas and 1 L of helium gas contain the same number of molecules under a constant pressure and temperature. However, the oxygen gas may weight more.


by weird rounding rules I meant like, if its odd you round up, if even you round down. Stuff like that. Completely off the wall rules.

###$.

I forgot. You asked molar mass. I just gave you the weight.

OK. You have the weight. Then you simply multiply it by molar mass constant, which is 1 g/mol.

So the weigh is 180.15588. The molar mass is weight* 1 g/mol = 180.15588 g/mol.

As for Avogadro's law, as far as I know, it just uses the idea that the density of vapor can be used to derive the molar mass. Why would you need to know that?

How do you know that glucose is C6 H12 O6? I asked the Internet.

Why is that the name and not something else with different numbers? Because it isn't.

How do I know the weight of the seperate elements? I checked the table, which you also should have. If not, I understand the use of the Avogadro's law.

What are isotopes? You know that the world, all the stuff in it, everything around you, consists of tiny particles, called atoms. The atoms consist of the nucleus and electrons around it. The nucleus is composed of protons and neutrons. (Simplified version)

The protons have a charge of +1 and the electrons have the charge of -1. The neutrons have no charge. Now, you know which atom a particular atom is, by counting the number of protons. It is always the same. However, the number of neutrons can vary. For example, carbon always has 6 protons. Always. However, there are different carbons. Carbon-12 has 6 protons and 6 neutrons, carbon-13 has 6 protons and 7 neutrons. These are different isotopes.

I am not good at chemistry, btw.

zausel wrote:Your teacher should give you that information. knowing glucose is C6 H12 O6 is something you should be given to do your math. Unless your teacher is a hard ass and wants you to memorize that. The weight should also be given to you. Might want to ask the teacher to make sure. My teacher gave us the info.

So did mine, but I wasn´t sure if there wasn´t a way of working it out on your own somehow if you haven´t memorized it.

New question then: How does my teacher (our chemistry book, people in general) know glucose has that chemical formula (that´s the word, isn´t it?) and not a different one? How did they find out?

Hydrogen is a group of isotopes, isotopes are a specific within that group.
1) hydrogen
a)Protium
b) Deuterium
c) Tritium

I suppose I´d have to memorize these terms? I tend to think you either magically know them or you don´t. Seems like that´s not the case and there actually is learning involved.

1L of oxygen gas and 1 L of helium gas contain the same number of molecules under a constant pressure and temperature. However, the oxygen gas may weight more.

Why? If you just explained it and I missed it, I apologize.

by weird rounding rules I meant like, if its odd you round up, if even you round down. Stuff like that. Completely off the wall rules.

You mean the weight CTOA wrote down?

CantThinkOfAny wrote:OK. You have the weight. Then you simply multiply it by molar mass constant, which is 1 g/mol.

Why is it 1g/mol and not something else? Does it ever change (seeing as it´s called "constant", I´d guess it doesn´t, but what point is there in multiplying anything with 1, could just as well leave that part out)?

As for Avogadro's law, as far as I know, it just uses the idea that the density of vapor can be used to derive the molar mass.

How?

Why would you need to know that?

My teacher asked us to find out until the next lesson. He can be evil so I wouldn´t want to anger him by not knowing anything at all (not that it was unusual).

Why is that the name and not something else with different numbers? Because it isn't.

How do I know the weight of the seperate elements? I checked the table, which you also should have. If not, I understand the use of the Avogadro's law.

Which parts of the table are relevant for the elements´ weight?

I still haven´t quite understood how Avogadro´s law is supposed to help me here.


Thanks for your help so far, zausel and CTOA. I think I at least got the part about isotopes. Sorry about more questions.

I am not good at chemistry, btw.

I´d like to tell that joke to my friends, but if I say it it isn´t funny anymore, because it is true.

Camelidae wrote:

zausel wrote:Your teacher should give you that information. knowing glucose is C6 H12 O6 is something you should be given to do your math. Unless your teacher is a hard ass and wants you to memorize that. The weight should also be given to you. Might want to ask the teacher to make sure. My teacher gave us the info.

So did mine, but I wasn´t sure if there wasn´t a way of working it out on your own somehow if you haven´t memorized it.

New question then: How does my teacher (our chemistry book, people in general) know glucose has that chemical formula (that´s the word, isn´t it?) and not a different one? How did they find out?

Hydrogen is a group of isotopes, isotopes are a specific within that group.
1) hydrogen
a)Protium
b) Deuterium
c) Tritium

I suppose I´d have to memorize these terms? I tend to think you either magically know them or you don´t. Seems like that´s not the case and there actually is learning involved.

1L of oxygen gas and 1 L of helium gas contain the same number of molecules under a constant pressure and temperature. However, the oxygen gas may weight more.

Why? If you just explained it and I missed it, I apologize.

by weird rounding rules I meant like, if its odd you round up, if even you round down. Stuff like that. Completely off the wall rules.

You mean the weight CTOA wrote down?

I´d like to tell that joke to my friends, but if I say it it isn´t funny anymore, because it is true. [/quote]

Nah lol. I have to look some of this stuff up. The only way you could work it out on your own is if you knew the process to figure it out by using real glucose and using the process the white coated scientist used to figure it out. Just having the numbers is easier.

and no, Those were just examples. You dont need to memorize them, unless your teacher says so.

They found it out the same way they found out about atoms, magic. I kid. Im not to sure of the process, but you just take some glucose and do some test. Bout all I know.

Oxygen weights more than hydrogen.