How do you go about solving this? A sample of table sugar (sucrose, C12H22O11) has a mass of 1.202 g. Calculate the number of moles of C12H22O11 contained in the sample.?

Question

jfraser · Answer

do you know how to use the periodic table and the formula to find the $molar \space mass$ of a compound?

notstar · Answer

Yes, I do. is there a way to set it up?

jfraser · Answer

find the molar mass of sucrose for me, first

notstar · Answer

I've gotten 342.30 (342.29648)

notstar · Answer

342.30 g (342.29648 g)*sorry forgot to add the grams "g" there

jfraser · Answer

good. now what does the "molar mass" really mean?

jfraser · Answer

it means that 1 mole of sucrose will weigh 320g. and one mole is a lot of pieces

jfraser · Answer

it's a ratio, more than anything else$$\frac{342g}{1 mole}$$

jfraser · Answer

the molar mass of sucrose is 342g, but you don't have 342g, you've only got 1.202g. You've got a whole lot less than one mole, but $how \space much$ of a mole is it?

jfraser · Answer

use the ratio of molar mass as a conversion fraction. Start with the mass of sucrose you have, 1.202g, and create a fraction to multiply

jfraser · Answer

$$1.202\cancel{g \space sucrose} * \frac{1 \space mole \space sucrose}{342 \cancel{g \space sucrose}}$$

notstar · Answer

wait, you lost me there sorta. when I divided 1.202 by 342 I got a ludicrously low number: 0.00351461988ect.
Did I mess up somewhere or should I go ahead and round that number out giving me to about 0.003. if so, is that my final answer?

jfraser · Answer

you should get a ludicrously low number.

jfraser · Answer

ONE mole of sucrose should weigh 342g. You've got a whole lot LESS than 342g, so you should have a whole lot LESS than 1 mole of sucrose.

0.0035 moles is a whole lot less than 1, so you're right

notstar · Answer

Oh, so my I was right there. I had to double check there to make sure everything was right for a minute. Thanks alot JFraser for the help! n_n

notstar · Answer

I would give you a medal but, I have no idea how to do that so a heartfelt thanks will have to do :)

jfraser · Answer

You're very welcome.

(next to my name, click on "best response". that will give the medal.)