How are you studying for Chem? (1 Viewer)

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nwatts

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jm1234567890 said:
your welcome to apply... just write a damn good application.
Would nosadness increase his chances of gaining a modstick if he wrote his application in poetry form?
 
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I'll get back on topic since you people cocked up the topic, here are my notes styrene/polystyrene

Styrene is the monomer used to create polystyrene, the systematic name for styrene monomer is ethenylbenzene, and polystyrene systematic name is polyethenylbenzene or polyphenylbenzene

Polystyrene comes in 2 distinct types, PS(Polystyrene) & PS Foam (styrofoam).

Polystyrene is a hard, clear, brittle plastic used in audiocassette/CD cases. PS Foam (known as expanded polystyrene with 95% air and 5% polystyrene), having the tradename of Styrofoam used by the general public,
Styrofoam is made by blowing hot gas through polystyrene liquid prior cooling & solidification, used in disposable drinking cups (foam cups), eskies, packing materials, & fast food containers due to its excellent ability as insulator, Styrofoam is also generally lightweight.

 

Dreamerish*~

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Thanks Casmira.

There's another thing I'm confused about.

What is the the colour of the precipitate iron (II) hydroxide? That is, when hydroxide ions are added to a solution of iron (II).

Some textbooks say white turning quickly to brown, but others - and my tutoring notes - say grey-green. I asked Nit and Mitochondria and they both said grey-green. This morning I emailed my new tutor and he said it's white turning to brown.

Does anyone remember specifically what colour iron (II) hydroxide was during their precipitation prac? I remember vaguely that everything turned out the way I expected it to, and I've always known iron (II) hydroxide to be grey-green.
 

MedNez

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Dreamerish*~ said:
What is the the colour of the precipitate iron (II) hydroxide? That is, when hydroxide ions are added to a solution of iron (II).
White to brown with NaOH, my notes say.

CC also agrees. Page 199 Table 6.1, "Tests used to identify cations".
 
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Dreamerish*~ said:
Thanks Casmira.

There's another thing I'm confused about.

What is the the colour of the precipitate iron (II) hydroxide? That is, when hydroxide ions are added to a solution of iron (II).

Some textbooks say white turning quickly to brown, but others - and my tutoring notes - say grey-green. I asked Nit and Mitochondria and they both said grey-green. This morning I emailed my new tutor and he said it's white turning to brown.

Does anyone remember specifically what colour iron (II) hydroxide was during their precipitation prac? I remember vaguely that everything turned out the way I expected it to, and I've always known iron (II) hydroxide to be grey-green.
i remember it went brown for me, maybe they had higher concetrations? lower concetrations?
 

Haku

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i think for the white to brown its actually Iron(III)
not too sure on that...i think when u put that into NaOH solution it goes from white to brown.

anywayz, i am currently writing out an application form to jimo...hope i will pass! :rolleyes:

Q: how does adding Chronium to steel (steel is iron with 1.5% carbon right?) make it more resistant to corrosion? also what does molybdemum do when added to steel?
 
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Dreamerish*~

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nosadness said:
i think for the white to brown its actually Iron(III)
not too sure on that...i think when u put that into NaOH solution it goes from white to brown.

anywayz, i am currently writing out an application form to jimo...hope i will pass! :rolleyes:

Q: how does adding Chronium to steel (steel is iron with 1.5% carbon right?) make it more resistant to corrosion? also what does molybdemum do when added to steel?
Is that shipwrecks?
 

Haku

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Q: how does adding Chronium to steel (steel is iron with 1.5% carbon right?) make it more resistant to corrosion? also what does molybdemum do when added to steel?

to the iron thingy, i was right. the brown precipitate is iron(iii)(aq) + NaOH(aq) give Fe(OH)3, a brown precipitate. i think it only stay white for a second or so.

anywayz Fe(OH)2 is like dirty green or grey-green thats what u guys call it.
 

Haku

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Dreamerish*~ said:
Is that shipwrecks?
yea its in shipwrecks.

so is steel like 1.5% carbon with iron?...and whats the thingy with like 0.1% and 0.8% carbon

about the cromium and molybdmum stuff help please
 

Dreamerish*~

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nosadness said:
anywayz Fe(OH)2 is like dirty green or grey-green thats what u guys call it.
I don't mean to sound like a prick, but did you, by any chance, get that from me?

I was very unsure about this, because my sources contradict each other, however, I asked my tutor and he said iron (II) hydroxide is creamy white, quickly turning to brown. I think I'm going to go with that.

If you got it from somewhere else, where? This thing is really annoying me. :p
 

Haku

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Dreamerish*~ said:
I don't mean to sound like a prick, but did you, by any chance, get that from me?

I was very unsure about this, because my sources contradict each other, however, I asked my tutor and he said iron (II) hydroxide is creamy white, quickly turning to brown. I think I'm going to go with that.

If you got it from somewhere else, where? This thing is really annoying me. :p
wat u mean? i wrote that my self.

as the info state Iron(iii) the most commonly occuring iron ion is brown when mixed with NaOH, and iron(ii) is green. trust me. a friend is 2nd year uni does chemistry in advanced science and he looked it up too!
 

Dreamerish*~

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nosadness said:
wat u mean? i wrote that my self.

as the info state Iron(iii) the most commonly occuring iron ion is brown when mixed with NaOH, and iron(ii) is green. trust me. a friend is 2nd year uni does chemistry in advanced science and he looked it up too!
Yeah, I asked our Resident Chemist and Mitochondria (both of them know what they're talking about) and they told me that it's grey-green.

Then I asked my tutor, who has been a chemist his whole life, and he said it's creamy white turning to brown, which is what CC says.

In desperation, I called the HSC helpline, which gave me a third answer - green turning to brown.

I'm going to school next week and finding out for myself. '-_-

EDIT: Oh but this is really specific. :p I want to know because I'm just too curious, but if you're panicking over it - don't. The main thing is to identify that there is a precipitate.
 

Haku

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Dreamerish*~ said:
Yeah, I asked our Resident Chemist and Mitochondria (both of them know what they're talking about) and they told me that it's grey-green.

Then I asked my tutor, who has been a chemist his whole life, and he said it's creamy white turning to brown, which is what CC says.

In desperation, I called the HSC helpline, which gave me a third answer - green turning to brown.

I'm going to school next week and finding out for myself. '-_-

EDIT: Oh but this is really specific. :p I want to know because I'm just too curious, but if you're panicking over it - don't. The main thing is to identify that there is a precipitate.
lol, ull prob get a 4th answer. i think u should stay with grey green for iron(ii)

anywayz can anyone answer my question on steel?
 

Haku

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lol, thanks for that.

thought that this forum is going everywhere with question might as well come out with another random...
 

Captain Gh3y

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Molybdenum:

- Increases strength and hardness at high temp
- Increases resistance to corrosion
- Makes it easier to weld
- Makes it less brittle

Molybdenum steel is used in aircraft, vessles for use under high pressure and in car axles.
 

Haku

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thanks, so basically Increases strength and hardness at high temp

and how does chronium help to resist corrosion when added to iron.

and is steel iron with 1.5% carbon?

and do we need to know those thing like wraught iron and stuff with diff amount of carbon in them?
 
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