Help with calculations using molar mass

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Discussion Overview

The discussion revolves around understanding the calculation of moles using the formula that relates mass and molar mass. Participants seek clarification on the steps involved in rearranging the equation and performing dimensional analysis.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant cites the formula for calculating moles and asks for clarification on how to derive the equation mol = g x (mol/g).
  • Another participant questions the implications of dividing by the molar mass in the context of the formula.
  • A different participant explains the meaning of the equation, providing an example calculation with carbon to illustrate how to find the number of moles from a given mass.
  • One participant reiterates the original formula and presents a dimensional analysis, suggesting that the analysis confirms the relationship between grams and moles.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the original question and the steps involved in the calculations. There is no consensus on the clarity of the initial query, and multiple interpretations of the formula and its application are present.

Contextual Notes

Some participants may have differing assumptions about the clarity of the question posed, and the discussion includes various interpretations of the formula and dimensional analysis without resolving these differences.

Grace Otto
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So my chemistry teacher said that: Moles of a compound = mass of the sample (grams) ÷ molar mass of the compound (grams/mol)

So how do i get from there to the equations mol = g x (mol/g)??

I would like to know the steps involved i.e. rearranging the equation, dimensional analysis

Thanks!
 
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What happens when you "÷ molar mass of the compound (grams/mol)" ?
 
Im not sure exactly what your question is because it did not really make sense. But the meaning of that equation is to tell you the amount of moles that are in a certain quantity of a molecule. For example:
If there are 18 grams of carbon we can figure out how many moles there are by using the equation.

moles=amount/molar mass

That is, moles = 18/12
moles = 1.5
So there are 1.5 moles in 18 grams of carbon.
Good Luck from a fellow chem student
 
Grace Otto said:
So my chemistry teacher said that: Moles of a compound = mass of the sample (grams) ÷ molar mass of the compound (grams/mol)
The dimensional analysis is already done, right here, but I'll restate it in nicer format. ##\frac{[g]}{[g/mol]}=[g]\frac{1}{[g/mol]}=[g][mol/g]=[mol]##. Note that dividing by a fraction is simply multiplication by it's reciprocal.
 

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