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#1
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Anyone good with chem?
I'm having a bit of trouble on this one problem. It doesn't sound like a combustion problem, because it would normally mix with 02 to make CO2 and H20 but I cant figure out how to write a balanced chemical equation out of it, because it doesnt specify what happens to the sulfer:
When M2S3(s) is heated in air, it is converted to MO2(s). A 4.000 g sample of M2S3(s) shows a decrease of 0.277g when heated in air. What is the atomic mass of M. Report your answer to 1 decimal place. Any help would be greatly appreciated p.s. M is an unspecified element
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Tim 92 Liquid Silver SVX 5MT 2009 BMW Z4 (Gone) 2012 Camry V6 SE |
#2
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i don't know, but i do know that:
6pack + 12hotwings = CH4
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Alan 1987 928 S4 (Black) SOLD! 1997 SVX LSi (Ebony) SOLD! 2005 Legacy GT (Silver) [Cobb Stg 2+] SOLD! 1987 928 S4 (Black) SOLD! 2005 Forester XT Premium (Crystal Gray Metallic) SOLD! 2008 Lancer Evolution X MR (Apex Silver) [Cobb Stg 1+] 2015 Outlander Sport 2.4GT AWD (Mercury Gray) 2013 G37xS (Obsidian Black) |
#3
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I haven't done this in a while (11 years maybe) so I'm just looking at the numbers.
M2S3=4.0g M2 = .277g M = .138 S3 = 3.723g S = 1.274 Atomic weight of S = 32.065 M is 10.8% the weight of S Atomic weight of M = 3.473?? Probably not right but there is an S3CL2 compound so that's probably the right answer.
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
#4
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The oxygen is missing in your calculations, isnt it?
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Tim 92 Liquid Silver SVX 5MT 2009 BMW Z4 (Gone) 2012 Camry V6 SE |
#5
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found out an answer yet?
Here's my thought process (not a chemist BTW). And the lack of subscripts makes this look ugly, anyway.... set X=number of mole (fractional it turns out in this case) of each of the chemical elements - so 2units for M and 3 of S in the original state. Also, the units for M, S and O are atomic weights e.g. S=32.065g/mole. Note, we have two unknowns and two equations: a) unknown #1 is the atomic weight of M, and b) the number of moles used to form the 4g sample. Mathematically, M*2*X + S*3*X = 4g (where X=the part of a mole present). To verify, look at the units, i.e., S=32.065g/mole, 3 is dimensionless and X=number of moles - so left side of equation reduces to grams - which matches right side. using same thought process, 2*(M*X +O2*X) = 4-0.277 or m2*X + O4*X=4-0.277, or M2*X + O4*X + 0.277 = 4 Why? Conserving the number of M molecules in the reaction means 4 oxygen molecules form assuming reaction went to completion. Also, we were given the compound got 0.277g lighter during the reaction. Now, since the number of M atoms remains constant (remember, we are looking for the number of moles used in the oxidation reaction) and last time I checked, 4=4, so we can set one side equal to the other: M*2*X + S*3*X = M*2*X + O*4*X + 0.277, then subtracting M2*X from both sides you get 3*S*X=4*O*X+.277 then putting in weights for sulpher and oxygen: 3*32.065*X=4*15.994*X+.277 and solving for X -> X=0.0086 moles Since we now know the number of moles in the original equation, the only unknown is the atomic weight for M, so going back to the original equation 2*M*0.0086 + 3*32.065*0.0086 = 4, so 2*M*0.0086=3.1727, or M=184.5 g/mole (atomic weight) plugging the number for the atomic weight for M into either equation yields correct results, so a chemist might cringe, but this is how a physicist approached the problem. Last edited by lee; 10-03-2005 at 11:10 AM. |
#6
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Quote:
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2008 Mazdaspeed3 GT 1985 Toyota MR2 (10 yr project) Think of how stupid the average person is, and realize half of them are stupider than that. -George Carlin |
#7
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Quote:
__________________
Alan 1987 928 S4 (Black) SOLD! 1997 SVX LSi (Ebony) SOLD! 2005 Legacy GT (Silver) [Cobb Stg 2+] SOLD! 1987 928 S4 (Black) SOLD! 2005 Forester XT Premium (Crystal Gray Metallic) SOLD! 2008 Lancer Evolution X MR (Apex Silver) [Cobb Stg 1+] 2015 Outlander Sport 2.4GT AWD (Mercury Gray) 2013 G37xS (Obsidian Black) |
#8
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Quote:
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#9
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Quote:
__________________
Alan 1987 928 S4 (Black) SOLD! 1997 SVX LSi (Ebony) SOLD! 2005 Legacy GT (Silver) [Cobb Stg 2+] SOLD! 1987 928 S4 (Black) SOLD! 2005 Forester XT Premium (Crystal Gray Metallic) SOLD! 2008 Lancer Evolution X MR (Apex Silver) [Cobb Stg 1+] 2015 Outlander Sport 2.4GT AWD (Mercury Gray) 2013 G37xS (Obsidian Black) |
#10
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I think he'd like C4-H8 better myself...
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-Jason (8/23/07-Present) 1995 Subaru SVX LSi (197k) Polo Green (#1102) 03/95 Mods: DDM Tuning 4500k 35w Low Beam HID, 100w H3 Bulbs, Extra Ground Cables, 15 minute $12.96 mod, svxfiles designed transmission mount (), sporting a "new" tail light bar, silver BBS rims, custom power steering cooler (one that doesn't dump ATF constantly), new negative lead cable, no more third or fourth gear (1977-Present) 1977 Chevrolet Corvette (81k) Silver (12/01/2011-Present) 2005 Subaru Outback 2.5i Limited 5MT (97k) I have a bad feeling about this. -Obi Wan Kenobi |
#11
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Quote:
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2008 Mazdaspeed3 GT 1985 Toyota MR2 (10 yr project) Think of how stupid the average person is, and realize half of them are stupider than that. -George Carlin |
#12
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Quote:
i frickin' hated chemistry in school.
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Alan 1987 928 S4 (Black) SOLD! 1997 SVX LSi (Ebony) SOLD! 2005 Legacy GT (Silver) [Cobb Stg 2+] SOLD! 1987 928 S4 (Black) SOLD! 2005 Forester XT Premium (Crystal Gray Metallic) SOLD! 2008 Lancer Evolution X MR (Apex Silver) [Cobb Stg 1+] 2015 Outlander Sport 2.4GT AWD (Mercury Gray) 2013 G37xS (Obsidian Black) |
#13
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Ahhh this problem is so confusing! Not quite figured out yet but i'll keep you posted. Thanks for your effors so far
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Tim 92 Liquid Silver SVX 5MT 2009 BMW Z4 (Gone) 2012 Camry V6 SE |
#14
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I'll try to better explain my steps (probably had too much of a "it ca be shown that" flavor), see edited text above.
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#15
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Quote:
Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
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