Ask me for chemistry help! (4 Viewers)

[Hermes1]

lol. u culd make a really good set of summary notes just with stuff posted in this thread.

With the production of LDPE i just say:
Initiation
Propagation
Termination
and i describe each.
with HDPE what should i say? do we even need HDPE?

 

[adz1098]

A chemist wanted to find the percentage of caco3 in 2g of limewater. He added 100 ml of 0.905 mol/l HCL which was more than enough to react with with the calcium carbaonate. After the bubbling had ceased, the resulting solution was titrated with sodium carbonate solution. 30.45 ml of 1.01 mol/l was required to react with the unreacted HCL.

 

[FCB]

- Temperature
- IF temp too high, favours the reverse reaction, decreasing yield of ammonia
- IF temp too low, not enough energy for the gases to react thus once again reducing the yield of ammonia

- Pressure
- IF pressure too high, favours the reverse reaction
- Pressure cannot be too low, as it will be expensive and dangerous

You go the pressure all wrong

 

[FCB]

lol. u culd make a really good set of summary notes just with stuff posted in this thread.

With the production of LDPE i just say:
Initiation
Propagation
Termination
and i describe each.
with HDPE what should i say? do we even need HDPE?

Talk about Z-N catalyst

 

[Qwertyuioplm]

Screening
Aeration
Flocculation
Sedimentation
Filtration
Disinfection/Chlorination

Wrong, you have forgotten a vital step of pH adjustment that occurs after screening.

 

[Qwertyuioplm]

lol. u culd make a really good set of summary notes just with stuff posted in this thread.

With the production of LDPE i just say:
Initiation
Propagation
Termination
and i describe each.
with HDPE what should i say? do we even need HDPE?

HDPE refer to Ziegler-Natta catalyst and its low temperature and pressure (100 degree celsius, 2 atmospheres)

 

[Reikira]

You go the pressure all wrong

Oh whoops lol. Mixed it up.

 

[UnrealAnchovies]

has *anyone* done industrial chem?!

 

[Midnight_Lotus]

- Temperature
- IF temp too high, favours the reverse reaction, decreasing yield of ammonia
- IF temp too low, not enough energy for the gases to react thus once again reducing the yield of ammonia

- Pressure
- IF pressure too high, favours the reverse reaction
- Pressure cannot be too low, as it will be expensive and dangerous

Pressure:
- High pressure favours the forward reaction (N2 + 3H2 <--> 2NH3)
- However high pressure is costly so it must be compromised (normally 150-250 atmospheres)

Temp:
Reaction is exothermic so will shift to reactants to absorb heat
While a low temp produces larger quantites of ammonia it takes a long time so a compromise is found (the higher the temp the faster the production (due to kinetic energy) but lower the yield) - around 450-500 C

 

[Midnight_Lotus]

has *anyone* done industrial chem?!

I do, cant say i studied much for it though :/

 

[Qwertyuioplm]

has *anyone* done industrial chem?!

There be 6 marks on sulfuric acid, some marks on a synthetic molecule, some marks on Le Chateliar and some marks on saponification... don't know the rest [teacher give hints randomly through class, I write down in back of book]

 

[UnrealAnchovies]

There be 6 marks on sulfuric acid, some marks on a synthetic molecule, some marks on Le Chateliar and some marks on saponification... don't know the rest [teacher give hints randomly through class, I write down in back of book]

weird, but awesome nonetheless.

 

[_deloso]

has *anyone* done industrial chem?!

Just did bits that I thought was important.

 

[kr73114]

how do you work out the molar heat of combustion when 30% of heat is lost to surrondings?

 

[RANK 1]

how do you work out the molar heat of combustion when 30% of heat is lost to surrondings?

just times your final answer by 0.7

 

[Hermes1]

Talk about Z-N catalyst

So in my notes this is what i say:

The polymerisation of HDPE uses an ionic ziegler-natta catalyst consisting of a mixture of compounds. In this process ethane molecules are added to the growing polymer chain on the surface of the catalyst, reducing branching.

 

[mangoz]

Does anyone know how TOMS work. All i remember is that it fires something into the atmosphere and that's where my thought process vanishes LOL.

 

[Hermes1]

TOMS is the name of a satellite instrument used to map global ozone levels.

 

[oyuck]

There are 2 moles of PbI(subscript2)

Find the no of moles of I(subscript2)

Do you need to find the molar ratio molarmass(Isubscript2)/molarmass(PbI(subscript2)
??

 

[mangoz]

TOMS is the name of a satellite instrument used to map global ozone levels.

No as in the process LOL. I'm pretty sure you have to know at least how one works with quite an amount of detail o.o