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## Stoichiometry

hey, if anyone can help me on this problem, that would be GREAT:

When M2S3(s) is heated in air, it is converted to MO2(s). A 4.000-g sample of M2s3(s) shows a decrease in mass of 0.277 g when it is heated in air. What is the average atomic mass of M?

M is the missing element that has to be solved for.
S is Sulfur and it is 32.07 amu

THXXXXXXXXXX
3 REPLIES 3

## Stoichiometry

On 9/23/2003 6:16:23 PM, bluedude20003 wrote:
>hey, if anyone can help me on
>this problem, that would be
>GREAT:
>
>When M2S3(s) is heated in air,
>it is converted to MO2(s). A
>4.000-g sample of M2s3(s)
>shows a decrease in mass of
>0.277 g when it is heated in
>air. What is the average
>atomic mass of M?
>
>M is the missing element that
>has to be solved for.
>S is Sulfur and it is 32.07
>amu
>
>THXXXXXXXXXX

First, come up with the process equation for the conversion, with the correct balance of the unknown sulfide to unknown oxide. What happens to the sulfur is irrelevant, all you need is how many sulfur atoms are replaced by oxygen atoms. The difference in atomic mass is divided into the change in mass of the sample to figure out how many moles of of unknown there are, which will allow you to figure out the atomic mass of the unknown.
TTFN,
Eden

## Stoichiometry

thx for explainin, but WHAT???? can u please be more clear, like step by step on what to do. BUT THANKS FOR HELPING.. I REALLY APPRECIATE IT

## Stoichiometry

When M2S3(s) is heated in air, it is converted to MO2(s). A 4.000-g sample of M2s3(s) shows a decrease in mass of 0.277 g when it is heated in air. What is the average atomic mass of M?

M is the missing element that has to be solved for.
S is Sulfur and it is 32.07 amu

> Figure out the balanc for the equation

M2S3 --> MO2

> The change in mass for the unknown is due to the difference of atomic weights of sulfur and oxygen as well as the difference in the number of atoms of sulfur and oxygen in their respective compounds.

> Calculate the number of moles of compound

> Calculate the atomic weight of the unknown atom

TTFN,
Eden
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