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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Kitty Kat on October 18, 2004, 07:57:15 AM

Title: Completing equation
Post by: Kitty Kat on October 18, 2004, 07:57:15 AM

Does any1 know how to complete this equation?
FeS + Cu2S + O2 -->

Title: Re:Completing equation
Post by: AWK on October 18, 2004, 08:26:21 AM

Depending on temperature and amount of oxygen you can obtain Fe2O3 and Cu2O or Fe3O4 and CuO.
Do reaction separately, eg
4FeS + 7O2 = 2Fe2O3 + 4SO2

Title: Re:Completing equation
Post by: Donaldson Tan on October 20, 2004, 03:25:48 PM

Cu₂S + 2O₂ -> 2CuO + SO₂

Title: Re:Completing equation
Post by: Tetrahedrite on October 20, 2004, 09:01:40 PM

Both of you are almost right!

2FeS + Cu2S + 7O2 -> Fe2O3 + 2CuO + 3SO3

Cuprite (Cu2O), magnetite (Fe3O4) and SO2 are unlikely to form in the presence of sufficient oxygen

Title: Re:Completing equation
Post by: AWK on October 21, 2004, 01:06:13 AM

Reaction wrote down by Tetrahedrite is only valid for 1:1 molar mixture of FeS and Cu₂S and SO₂ not SO₃ is produced in this way. To convert SO₂ to SO₃  a catalyst is needed.

Title: Re:Completing equation
Post by: Tetrahedrite on October 21, 2004, 02:18:27 AM

At high enough temperature no catalyst is required! We can safely assume a reaction such as this is not occurring at room temperature otherwise base metal mines all around the world would start catching fire! In the presence of the atmosphere in this case the thermodynamically stable species are CuO (tenorite), Fe2O3 (hematite, with time) SO2 at the earth's surface is unstable and will eventually be converted to sulfate and incorporated into the soil as a soluble salt.

Title: Re:Completing equation
Post by: AWK on October 22, 2004, 12:58:16 AM

At high enough temperature no catalyst is required!
If so, why SO3 is produced from FeS2 in two steps
4FeS2 + 11O2 = Fe2O3 + 8SO2
and
2SO2 + O2 =SO3