What is the Correct Formula of the Metal?

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Discussion Overview

The discussion revolves around a chemistry problem regarding the determination of the correct formula for a metal oxide based on given data about the metal and its reaction with oxygen. Participants explore the implications of the provided atomic mass and the mass of the resulting oxide, leading to various interpretations of the question.

Discussion Character

  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant expresses confusion about the question and does not attempt a solution.
  • Another participant suggests that the question may contain errors, proposing a revised version that clarifies the mass of metal X and its reaction with oxygen.
  • A different participant calculates the mass of metal X and the corresponding mass of oxygen, leading to a proposed ratio of metal to oxygen and a suggested formula of X2O3, identifying X as Aluminium.
  • Another participant challenges the applicability of the previous logic, pointing out inconsistencies in the atomic mass values derived from the question and suggesting that ignoring certain parts leads to different conclusions.
  • One participant defends the logic of the previous calculation, emphasizing that the answer depends on which parts of the question are considered erroneous.

Areas of Agreement / Disagreement

Participants do not reach a consensus; multiple competing views remain regarding the interpretation of the question and the validity of the calculations presented.

Contextual Notes

Participants note potential confusion arising from the atomic mass provided and the mass of the oxide, which may lead to different interpretations and calculations. The discussion highlights the dependence on which elements of the question are deemed correct or erroneous.

lioric
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Homework Statement
0.1 mol of metal X (Ar = 27) was burned in oxygen to give an oxide with mass of 5.1g. What is the formula of the metal oxide if it has a relative molecular mass of 30?

The choices are
XO
X2O3
XO2
X2O

The answer says X2O

But if I add up X2O the RMM is 70 not 30
Relevant Equations
This question is confusing
I don't understand how the RMM could be 30
I haven't gone into a solution cause I found this question confusing
 
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Something is definitely wrong with the question and the answer given.

My bet is it should read: "0.1 mol of metal X (Ar = 27) was burned in oxygen to give an oxide with mass of 5.1g. What is the formula of the metal oxide?"
 
I found the mass of the X by 27x0.1=2.7g
I subtracted 5.1g-2.7g=2.4g of oxygen
So changed the mass of oxygen to moles which = 0.15
Ratio it with 0.1 mol of X and I get 1:1.5
So X:O is 2:3 ratio
There for X2O3
Which makes sense cause At=27 is Aluminium
And Aluminium Oxide is Al2O3
 
Your logic is good but it doesn’t apply to what is asked. The truly confusing part is the “(Ar=27)” and the 5.1 g. :)

If we ignore that part, the rest of the question tracks normally.

If RMM=30:

XO case: atomic mass X = 14 (N, nonmetal)
X2O3 case: atomic mass X= -9 (not real)
XO2 case: atomic mass X=-2 (not real)
X20 case: atomic mass X=7 (Li)
This should be the end of the problem.

balanced equation

2Li (.1 mol) + 1/2O2 ——-> Li2O (.05 mol)

It does make 1.5 g of product. A dyslexic 5.1 g?
 
Last edited:
chemisttree said:
Your logic is good but it doesn’t apply to what is asked.

Let's not confuse the OP further. Question asks what is the formula and that's exactly what OP calculated, so their logic applies. Answer depends on which parts of the contradicting information given in the question one considers erroneous and decides to ignore.
 

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