Post by: Kaille on March 01, 2011, 10:41:20 pm
i've been stuck on this one question for ages!!! it'll probably pretty simple for you guys :P
Q. a sample of ethane, C2H6, contains 1.2 x 1023atoms of carbon.
How many molecules of ethane are present?
Post by: luken93 on March 01, 2011, 10:50:22 pm
Therefore, for every Ethane Atom there are two carbon atoms
Therefore, for every 1.2 x 10^23 of Carbon atoms, there are 0.6 x 10^23 Ethane Molecules (6.0 x 10^22)
Post by: HERculina on March 01, 2011, 10:56:58 pm
so i think the equation would be:
1.2 x 10^23 atoms of carbon = 2(x moles of ethane molecules times 6.02 x 10^25)
but imma not too sure o.o
EDIT: wait i dot get it too ... D:
Post by: Kaille on March 01, 2011, 10:58:40 pm
Post by: Water on March 01, 2011, 10:59:54 pm
Correction:
6.02 x 10^23 particles = avogrados number = 1 mole xD
To Find the mole . you have atoms of (Sample) / nA = mol
Post by: Hutchoo on March 01, 2011, 11:04:37 pm
Unit 1 sucks. If I get questioned on "WHO wuz da main perzon dat ENV3NteD dah P3rioDIk tabl3?????" I might slap someone.
Post by: dooodyo on March 01, 2011, 11:05:47 pm
Post by: HERculina on March 01, 2011, 11:07:26 pm
I wish I was doing this type of chemistry at the moment.
Unit 1 sucks. If I get questioned on "WHO wuz da main perzon dat ENV3NteD dah P3rioDIk tabl3?????" I might slap someone.
isnt the mole in unit 1 chem? xD
Post by: Hutchoo on March 01, 2011, 11:09:40 pm
5 weeks of pain and boringness. D:
Post by: Water on March 01, 2011, 11:10:38 pm
I wish I was doing this type of chemistry at the moment.
Unit 1 sucks. If I get questioned on "WHO wuz da main perzon dat ENV3NteD dah P3rioDIk tabl3?????" I might slap someone.
isnt the mole in unit 1 chem? xD
Just some history for you guys, might be inaccurate cause i watched it on a documentry, Lavoiser was a tax collector, and a chemist, causing the downfall of the Monarchy and uprising of the French Revolution through excessive taxing.
Yes, you heard me, The Father of Chemistry was a Tax Collector.
Post by: HERculina on March 01, 2011, 11:11:32 pm
Yeah.. but we haven't done focused on any fun chemistry..
5 weeks of pain and boringness. D:
D: i feel for you.
my chem teacher didnt like the history part anyway, so she tried to rush it :)
Post by: Kaille on March 01, 2011, 11:16:42 pm
What is the total mass of ethane?
Post by: luken93 on March 01, 2011, 11:28:52 pm
sorry, i've got another question.Is this the same question or do you mean Molar Mass (You probs don't know what this is yet...)
What is the total mass of ethane?
Post by: luken93 on March 01, 2011, 11:30:12 pm
Post by: nacho on March 01, 2011, 11:56:12 pm
when a question asks for amount of something, your answer will be in mol
What is a mol? A mol is the number of atoms contained 12.0 grams of Carbon-12. This number is 6.02 x 10^23 - a very large number.
The molar mass of something, for example, hydrogen is the mass of 1 mol of that substance. I.e, 6.02 x 10^23 (or 1 mole) of hydrogen atoms will weight approximately 1 gram (as given in your periodic table.)
With this knowledge, you can work out the mass, or amount in mol of anything, given you have at least 1 or the other. If you can make a logical link between the formulas and how they work, you are well on your way to acing stoich.
For example, the formula for working out mols is:
Why?
See how it works:
1 mol of hydrogen weighs 1 gram,
according to the periodic table the molar mass of hydrogen is 1 gram per mol, that is, if we have 1 mol of hydrogen atoms and weigh it, it will = roughly a gram.
So, if we have 2 grams of hydrogen, how many mol of hydrogen will we have? using
Post by: schnappy on March 02, 2011, 12:00:20 am
Post by: Mao on March 02, 2011, 01:57:47 pm
All i'll say is,
when a question asks for amount of something, your answer will be in mol
What is a mol? A mol is the number of atoms contained 12.0 grams of Carbon-12. This number is 6.02 x 10^23 - a very large number.
The molar mass of something, for example, hydrogen is the mass of 1 mol of that substance. I.e, 6.02 x 10^23 (or 1 mole) of hydrogen atoms will weight approximately 1 gram (as given in your periodic table.)
With this knowledge, you can work out the mass, or amount in mol of anything, given you have at least 1 or the other. If you can make a logical link between the formulas and how they work, you are well on your way to acing stoich.
For example, the formula for working out mols is:
Why?
See how it works:
1 mol of hydrogen weighs 1 gram,
according to the periodic table the molar mass of hydrogen is 1 gram per mol, that is, if we have 1 mol of hydrogen atoms and weigh it, it will = roughly a gram.
So, if we have 2 grams of hydrogen, how many mol of hydrogen will we have? using, where m= 2 and
= 1, we will have 2/1 = 2 mols of hydrogen.
A much easier way to think about it: Mr is given by g/mol, thus
(similar with concentration in mol/L, thus
Post by: Kaille on March 02, 2011, 06:06:46 pm
like the mass in grams. i figured it out and i get 3.0 grams. i divided the number of ethane molecules by avogadro's number.sorry, i've got another question.Is this the same question or do you mean Molar Mass (You probs don't know what this is yet...)
What is the total mass of ethane?
thanks for the help guys :)
Post by: Dream-Storm on March 08, 2011, 05:11:58 pm