Chemistry A, real simple for most people. Mol problems.

[Fishingaxe]

Chemistry A, real simple for most people. "Mol" problems.

Homework Statement

Hello, first I'd like to say thank you to this community as I have gotten a lot of help in the physics department before and is basically a big reason of me passing the class.

Now chemistry is here and I am having a little bit of trouble so I thought I'd put up a few problems here and you can look over my attempt of solving it and maybe help me along the way.


Problem A) A copper test shows to contain 0.126 mol of copper, the whole test weighs 8.562 g. Does the test contain of 100% copper?



Attempt to solve: n=m/M

n= 8.562g / 0.126*6.02*10^23
n = 8.562 / 7.585*10^22
n = 4.09*10^25.

^--- this is how far I've managed to come on my own. I know the solution is more or less done by now but I am having trouble with what to write, in terms of grams etc to finish off the question. I know that if the answer is not 8.562g the test doesn't contain of 100% copper. As said, don't know how to take it from here.

Problem B) A sugarcube has the mass 2.1g. The sugar is made of sackaros with the formula C₁₁H₂₂O₁₁

a) calculate "n" sackaros in the sugarcube.
b) calculate "n" carbonatoms in the sugarcube.

Attempt to solve: <---- This is where I am completely lost. I know that I have to use the formula n=m/M and I understand what the formula means. What I don't understand is how to get those numbers from "C₁₁H₂₂O₁₁". I am a complete novice when it comes to this. Any help is very much appreciated.





PS: Posted this in another chemistry section in this forum but I've realized that this is the homework section so I apologize.

 

[Saitama]

Attempt to solve: n=m/M

n= 8.562g / 0.126*6.02*10^23
n = 8.562 / 7.585*10^22
n = 4.09*10^25.

How do you get M=0.126*6.02*10^23?? And please define your variables.

Problem B) A sugarcube has the mass 2.1g. The sugar is made of sackaros with the formula C₁₁H₂₂O₁₁

a) calculate "n" sackaros in the sugarcube.
b) calculate "n" carbonatoms in the sugarcube.

Attempt to solve: <---- This is where I am completely lost. I know that I have to use the formula n=m/M and I understand what the formula means. What I don't understand is how to get those numbers from "C₁₁H₂₂O₁₁". I am a complete novice when it comes to this. Any help is very much appreciated.
.

To calculate the moles of sackaros, you need its molar mass. Can you calculate that?

 

[Fishingaxe]

How do you get M=0.126*6.02*10^23?? And please define your variables.



To calculate the moles of sackaros, you need its molar mass. Can you calculate that?

Thank you for helping, I had another thread up here that contained the exact same problems and already solved them with the help from borek and one other person as well.

I am much more familiar with these types of things now :)

 

[Borek]

https://www.physicsforums.com/showthread.php?t=723794