quick chemistry help

2008-04-02 18:16:43

#1

CanadianLoser: Meow :3 :3; +1,148|6985

k so im doing a lab on reacting lead with sulfur and im trying to do the equation

i have to do a chemical equation and find the percent composition for both lead (II) sulfide and lead (IV) sulfide then compare the answers with the observations i made.

i briefly remembering a stupid rule where sulfur is always S₈ when it is alone or something? so i'd assume the chemical equation for the lead (II) sulfide would be

Pb + S₈ --> PbS₈

since the valences cancel out so you dont have to criss-cross them down to find the sub-scripts

but for lead (IV) sulfide i can't just cancel out the valences, but i can minimize them so that the 4 valence on lead becomes 2 and cancel out the valence of 2 on sulfur.

so i have right now

Pb^-2 + S₈ ---> PbS_{what goes here?!?!}

so my question is:
what is the subscript on the sulfur in the product?

2008-04-02 18:28:46

#2

Gooners: Wiki Contributor; +2,700|7109

l0ollolol0ol0lolopllolwut

2008-04-02 18:34:46

#3

Brasso: member; +1,549|7107

Why would the Sulfur need a subscript of 8?

The only thing I can think of is BrINClHOF, but those are the diatomic elements. Not octa-atomic.

"people in ny have a general idea of how to drive. one of the pedals goes forward the other one prevents you from dying"

2008-04-02 18:36:46

#4

Smithereener: Member; +138|6793|California

I'm fairly certain that Lead (II) Sulfide is PbS. Pb has an oxidation # of +2, and Sulfur is -2. As far as I know, you can write it as Pb + S --> PbS. It doesn't seem right the way you did it, since S₈ has an oxidation # of 0, but +2 in the products - making it a redox reaction except the lead doesn't reduce (thus making it false).

I honestly don't know when S₈ comes to play. Only the regular diatomic elements.

2008-04-02 18:37:05

#5

CanadianLoser: Meow :3 :3; +1,148|6985

i know, but it just seems to work perfectly and i can swear my teacher told me about it being a special case but its sooo frustrating cause i cant find a reassuring resource

2008-04-02 18:39:04

#6

CanadianLoser: Meow :3 :3; +1,148|6985

Smithereener wrote:
I'm fairly certain that Lead (II) Sulfide is PbS. Pb has an oxidation # of +2, and Sulfur is -2. As far as I know, you can write it as Pb + S --> PbS. It doesn't seem right the way you did it, since S₈ has an oxidation # of 0, but +2 in the products - making it a redox reaction except the lead doesn't reduce (thus making it false).

I honestly don't know when S₈ comes to play. Only the regular diatomic elements.

yeah thats what i thought too, but when i try to do the percent compositions, using PBs₈ is like .5 % off of my observations, and using PbS is like 30 percent off.

2008-04-02 18:52:40

#7

S.Lythberg: Mastermind; +429|6924|Chicago, IL

Lead (II) sulfide is PbS, not PbS₈

Lead (III) sulfide is Pb₂S₃

Lead(IV) sulfide is PbS₂

S₈ is never found in a molecule, only the elemental form of Sulfur.

Last edited by S.Lythberg (2008-04-02 18:53:55)

2008-04-02 18:57:21

#8

Brasso: member; +1,549|7107

S.Lythberg wrote:
Lead (II) sulfide is PbS, not PbS₈

Lead (III) sulfide is Pb₂S₃

Lead(IV) sulfide is PbS₂

S₈ is never found in a molecule, only the elemental form of Sulfur.

This man here is correct.

But Lead (IV) and Lead (II) will be the ones you use most anyway. I've never seen Lead (III) in a school equation.

"people in ny have a general idea of how to drive. one of the pedals goes forward the other one prevents you from dying"

2008-04-02 18:58:25

#9

nukchebi0: Пушкин, наше всё; +387|6801|New Haven, CT

S.Lythberg wrote:
Lead (II) sulfide is PbS, not PbS₈

Lead (III) sulfide is Pb₂S₃

Lead(IV) sulfide is PbS₂

S₈ is never found in a molecule, only the elemental form of Sulfur.

He knows.

2008-04-02 18:58:46

#10

S.Lythberg: Mastermind; +429|6924|Chicago, IL

haffeysucks wrote:
S.Lythberg wrote:
Lead (II) sulfide is PbS, not PbS₈

Lead (III) sulfide is Pb₂S₃

Lead(IV) sulfide is PbS₂

S₈ is never found in a molecule, only the elemental form of Sulfur.
This man here is correct.

But Lead (IV) and Lead (II) will be the ones you use most anyway. I've never seen Lead (III) in a school equation.

or anywhere, it's unstable...

and you don't need to use S₈ in the balancing, only monatomic S

2008-04-02 19:02:47

#11

CanadianLoser: Meow :3 :3; +1,148|6985

S.Lythberg wrote:
haffeysucks wrote:
S.Lythberg wrote:
Lead (II) sulfide is PbS, not PbS₈

Lead (III) sulfide is Pb₂S₃

Lead(IV) sulfide is PbS₂

S₈ is never found in a molecule, only the elemental form of Sulfur.
This man here is correct.

But Lead (IV) and Lead (II) will be the ones you use most anyway. I've never seen Lead (III) in a school equation.
or anywhere, it's unstable...

and you don't need to use S₈ in the balancing, only monatomic S

yeah im sure u guys are right, i think some of my observations were off cheers for the help guys +1 to those who helped

2008-04-02 19:10:55

#12

CommieChipmunk: Member; +488|7047|Portland, OR, USA

No your observations were right, just applied in the wrong way. In its elemental form, Sulfur is "S₈" much like you see hydrogen in its diatomic elemental form H₂, but in its elemental form, it doesn't bond with anything because it's neutral. So a sulfur ion will bond with lead to form PbS (assuming that lead is in its 2+ oxidation state, if not it'll take on the other forms mentioned by Lythberg).

2008-04-02 19:15:29

#13

CanadianLoser: Meow :3 :3; +1,148|6985

so it would be written

Pb + S --> PbS

or

Pb + S₈ --> PbS

?

2008-04-02 19:16:46

#14

CommieChipmunk: Member; +488|7047|Portland, OR, USA

the first one

and actually if they are ions forming a precipitate it would be

Pb⁺² + S^-2 --> PbS

Last edited by CommieChipmunk (2008-04-02 19:21:09)

2008-04-02 19:17:13

#15

S.Lythberg: Mastermind; +429|6924|Chicago, IL

CommieChipmunk wrote:
the first one

2008-04-02 19:17:57

#16

CanadianLoser: Meow :3 :3; +1,148|6985

thanks again guys

BF2S Forums quick chemistry help

Smithereener wrote:

S.Lythberg wrote:

S.Lythberg wrote:

haffeysucks wrote:

S.Lythberg wrote:

S.Lythberg wrote:

haffeysucks wrote:

S.Lythberg wrote:

CommieChipmunk wrote:

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