how was it (3 Viewers)

[nicola.jade.xx]

i thought it was good, im really happy loveddd the polyethylene question and the nitogen oxides.
the calculations were a bit weird, apart from the ethanol one but i reckon it was schweeeet and the galvanic one and equilibrium onee? wwwwwwwtf lol

shipwrecks was surprisingly easyyy

 

[flyace]

Conquering Chemistry says pH comes first. But i got it wrong nooooooo

And NH3 + HCl = NH4Cl

i think

 

[Buckley7]

It was bad. Time for physics =P

 

[FlameFromBeyond]

Conquering Chemistry says pH comes first. But i got it wrong nooooooo

And NH3 + HCl = NH4Cl

i think

pH comes first as you make the water alkaline to promote the formation of flocs. You do this through adding lime (CaCO3) --> flocs and precipitates form --> sedimentation...

 

[gurmies]

I got 1.77% too

 

[TechnIx]

Conquering Chemistry says pH comes first. But i got it wrong nooooooo

And NH3 + HCl = NH4Cl

i think

Excel here says the process as follows:

The Catchment Area
Screening (large matter screened out)
Coagulation/Flocculation/Sedimentation
Filtration (sand bed)
Oxidation (such as adding chlorine dioxide, or ozone)
Water Stabilization (pH chemically stabilised, by adding lime or sometimes CO2)
Disinfection

pH comes first as you make the water alkaline to promote the formation of flocs. You do this through adding lime (CaCO3) --> flocs and precipitates form --> sedimentation...

See above.....Excel seems to contradict Conquering Chemistry.....

 

[sam5]

for the acid question:

Was it ok to say : HCl + NH3 --> NH4+ + CL- ?

And did u say that acid 1 and acid 2 were both strong but acid 2 was less concentrated than acid1 ?

 

[chrisnumber1]

that was easy, i know that pple are bitching about multi-choice...sorry that u had to think or had to of studied the coarse. just look at how much stuff they didnt ask....nothing n the development of acid deffinitions, no batteries, no nuclear chemistry , no field of chemistry, no Ozone...therefore easy as. i reckon i got raw mark approx 91-ish, 14/15 M/C, 55+/60 and 22/25 for industrial chem cos i forgot the emulsion stuff so probs 1/2 and maybe a mark or two off for the marker.

 

[mitchwong650]

for the acid question:

Was it ok to say : HCl + NH3 --> NH4+ + CL- ?

And did u say that acid 1 and acid 2 were both strong but acid 2 was less concentrated than acid1 ?

no, one was strong and one was weak

that's due to the equivalence point's varying so much.

 

[annabackwards]

for the acid question:

Was it ok to say : HCl + NH3 --> NH4+ + CL- ?

And did u say that acid 1 and acid 2 were both strong but acid 2 was less concentrated than acid1 ?

I put that too and my teacher said it should be fine because NH4Cl is actually a weak acid and so would dissociate when in solutions anyway. I'm hoping she's right

no, one was strong and one was weak

that's due to the equivalence point's varying so much.

Yeah, that's what i put.

 

[sam5]

no, one was strong and one was weak

that's due to the equivalence point's varying so much.

i wouldnt have thought that the pH of a weak acid could be as low as 2.

 

[sam5]

I put that too and my teacher said it should be fine because NH4Cl is actually a weak acid and so would dissociate when in solutions anyway. I'm hoping she's right

i hope so too!

 

[Kaatie]

it was great although 14 and 15 were hard. and i forgot what colour barium ions turn and what is the catalyst in polymerisation. couldnt draw glycerol... never have before in my life. the battery question was explained to us in the hols by my chem teacher the EXACT SAME BATTERY . graph was good, nitrogen oxide q was great. thank god no steps of solvay process. nailed the contact process and location of solvay plant. however im ranked 2nd so i will never find out my true mark if i beat 1st place . anyways best exam yet . hoping for band 5!

 

[Drewx]

Excel here says the process as follows:

The Catchment Area
Screening (large matter screened out)
Coagulation/Flocculation/Sedimentation
Filtration (sand bed)
Oxidation (such as adding chlorine dioxide, or ozone)
Water Stabilization (pH chemically stabilised, by adding lime or sometimes CO2)
Disinfection



See above.....Excel seems to contradict Conquering Chemistry.....

Wikipedia says that it's pH adjustment -> flocculation -> settling

 

[flyace]

Excel here says the process as follows:

The Catchment Area
Screening (large matter screened out)
Coagulation/Flocculation/Sedimentation
Filtration (sand bed)
Oxidation (such as adding chlorine dioxide, or ozone)
Water Stabilization (pH chemically stabilised, by adding lime or sometimes CO2)
Disinfection



See above.....Excel seems to contradict Conquering Chemistry.....

yeah i thought pH was last as well but the conquerin logic seems to be right aswell. dunnoooo

:mad1:

 

[flyace]

it was great although 14 and 15 were hard. and i forgot what colour barium ions turn and what is the catalyst in polymerisation. couldnt draw glycerol... never have before in my life. the battery question was explained to us in the hols by my chem teacher the EXACT SAME BATTERY . graph was good, nitrogen oxide q was great. thank god no steps of solvay process. nailed the contact process and location of solvay plant. however im ranked 2nd so i will never find out my true mark if i beat 1st place . anyways best exam yet . hoping for band 5!

holy fuk there was a battery question?


please tell meh ur tlkin bout the galvanic cell thingay

 

[annabackwards]

Wikipedia says that it's pH adjustment -> flocculation -> settling

That's wikipedia which is predominately American. HSC text books say pH adjustment is just before flouridation. Also, pH adjustment has nothing to do with the lime added with aluminium sulfate (despite what some people will be saying).

 

[sam5]

i think its a very bad question. Its too subjective, and not only students but textbooks and resources are conflicting. Very bad question.

 

[4theHSC]

That's wikipedia which is predominately American. HSC text books say pH adjustment is just before flouridation. Also, pH adjustment has nothing to do with the lime added with aluminium sulfate (despite what some people will be saying).

yes i said pH adjustment is first because the text book said so! as it increases precipitation

 

[shady145]

i wouldnt have thought that the pH of a weak acid could be as low as 2.

concentrated weak acid