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

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Discussion Overview

The discussion revolves around solving mole-related problems in chemistry, specifically focusing on determining the number of moles of substances based on given mass and molar mass. The problems presented involve calculations related to copper and sucrose (sugar), with participants seeking assistance on how to approach these calculations.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant presents a problem involving a copper test and attempts to calculate the number of moles using the formula n=m/M, but expresses uncertainty about how to conclude whether the test contains 100% copper.
  • Another participant questions how to derive the molar mass (M) from the provided information, specifically asking for clarification on the calculation involving Avogadro's number.
  • In the second problem regarding a sugarcube, participants discuss the need to calculate the molar mass of sucrose (C11H22O11) to find the number of moles, but one participant admits to being lost on how to extract the necessary values from the chemical formula.
  • There is acknowledgment of previous assistance received in a related thread, indicating some familiarity with the concepts but still seeking clarification on specific calculations.

Areas of Agreement / Disagreement

Participants express uncertainty about specific calculations and definitions, indicating that there is no consensus on how to proceed with the problems presented.

Contextual Notes

Participants have not resolved the calculations for the molar mass of sucrose or the implications of the copper test results, leaving these areas open for further discussion.

Fishingaxe
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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.
 
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Fishingaxe said:
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?
 
Pranav-Arora said:
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 :)
 

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