Calculating Empirical Formula Using Molecular Mass

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Discussion Overview

The discussion revolves around determining the empirical formula of a compound composed of carbon and hydrogen, given its molecular mass of 42. Participants explore methods for deriving the empirical formula, considering both theoretical and practical aspects of the problem.

Discussion Character

  • Homework-related
  • Exploratory
  • Mathematical reasoning

Main Points Raised

  • One participant expresses uncertainty about how to approach the problem and seeks guidance.
  • Another participant proposes a method to derive the molecular formula, suggesting C3H6 as a possibility, leading to the empirical formula CH2, while acknowledging that there may be other interpretations.
  • A third participant notes that additional information, such as percentage composition, could aid in reducing ambiguity in determining the empirical formula.
  • A later reply affirms that CH2 is a valid answer but expresses discomfort with the assumptions made due to limited information.

Areas of Agreement / Disagreement

Participants generally agree that CH2 is a plausible empirical formula based on the calculations presented, but there is acknowledgment of the assumptions involved and the potential for other interpretations.

Contextual Notes

The discussion highlights the limitations of the provided information, particularly the lack of additional data that could clarify the empirical formula determination process.

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i know I am not supposed to ask for an answer to a problem, but could someone tell how to go about this question, it should be simple i think..

The molecular mass of a compound of carbon and hydrogen is 42. What is the empirical formula of the compound?

i don't really know what i should do, and guidence would be very appreciated!

thanks,
Alex
 
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This may not be correct - I'm just giving you my best guess.

Since it gives you a compound, there will be whole numbers of C and H. By looking at it, you can figure out that there would be 3 C (3 * 12.01 = 36.03) and 6 H (1.008 * 6 = 6.048). 36.03 + 6.048 ~ 42.

Therefore, the molecular formula is C3H6, which would mean the empirical formula would be CH2.

If you follow the same idea, it could also be C2H18, which would give CH9, but C2H18 isn't a possible compound.

There's probably a better and more correct way of figuring this out, but I think that CH2 should be correct. I'm only in high school, so I'll let someone more experienced in chemistry help you out.
 
Last edited:
With the information given, that sounds good.
A lot of the time, you might be given an extra bit of information, like the % composition or the products formed after conbustion, to help eliminate some of the trial and error guess work.
 
CH2 is one of the answers so that is right i believe and your explanation makes sence. i don't like how you have to assume though with the given information, but thank you so much for the help!
 

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