General thoughts: HSC chemistry 2015 (3 Viewers)

[SlimiJay]

what did you all talk about the haber process one? i thought i did a pretty good response but idk what i couldve added more

 

[malcolm21]

Oh, with the 5 mark radioisotope question, what would the marking guidelines for that be?
I had a good understanding of Americium 241, but I just don't see how they could pull 5 marks out of any answer...

whats that used for? I thought it was for household smoke detectors?

 

[Mr_Kap]

what did you all talk about the haber process one? i thought i did a pretty good response but idk what i couldve added more

if you mentioned data from the graph and trends from the graph then that is good.
I don't think you can get full marks without doing that.

 

[HecticLad]

Oh, with the 5 mark radioisotope question, what would the marking guidelines for that be?
I had a good understanding of Americium 241, but I just don't see how they could pull 5 marks out of any answer...

it did say discuss so you could have provided reasons why its properties are good and bad for the application, i think they will draw a fair bit of how you related its properties to it use, i think i wrote about 2 properties and 4 or 5 points about its use

 

[SlimiJay]

if you mentioned data from the graph and trends from the graph then that is good.
I don't think you can get full marks without doing that.

yeah i did that i spoke a lot about the graph but seemed not enough for 6/6
did anyone talk about rate of the reaction?
also heard someone wrote about catalyst

 

[Bozzin8R]

what did you all talk about the haber process one? i thought i did a pretty good response but idk what i couldve added more

Use the graph for temp + pressure, I did a lot on them and Le Chatelier's principle considerations and the "compromise" and I added stuff about the catalyst.

 

[reminisce1997]

for barium sulfate modifications one...
i talked about how barium can precipitate with not just sulfate but also phosphate so you had to use lower ph
and also how the presence of lead will precipitate also with chloride so it is better to use nitrate...
does this sound totally off??

 

[HecticLad]

yeah i did that i spoke a lot about the graph but seemed not enough for 6/6
did anyone talk about rate of the reaction?
also heard someone wrote about catalyst

yeah i talked about rate, catalyst, degradation of equipment due to high pressure and temp, and liquefying the nh3 to increase yeild as well as all the stuff on the graph

 

[aanthnnyyy]

what about the technology titration question? Never seen this in the syllabus

 

[band6man]

yeah i did that i spoke a lot about the graph but seemed not enough for 6/6
did anyone talk about rate of the reaction?
also heard someone wrote about catalyst

I talked about temp increasing rate of reaction which is why a high temp is used even though it decreases yield. I didn't add anything about the catalyst because it didn't ask.

 

[SlimiJay]

yeah i talked about rate, catalyst, degradation of equipment due to high pressure and temp, and liquefying the nh3 to increase yeild as well as all the stuff on the graph

does that mean i cant get 6/6 because i didnt talk about the catalyst?

 

[reminisce1997]

for barium sulfate modifications one...
i talked about how barium can precipitate with not just sulfate but also phosphate so you had to use lower ph
and also how the presence of lead will precipitate also with chloride so it is better to use nitrate...
does this sound totally off???

 

[kawaiipotato]

Nah it was an easy test. Only hard thing is if you haven't studied one of those battery things (like button cell etc..) as there was a 4 marker on it. I tried as best as i could and it seemed good enough for three marks but i'm thinking 2 marks just in case.

I found it easier than last years test but other people found it harder, but overall i think aligning will be around the same as last year.

GG when you only memorised Leclanche dry cell and it isnt listed in the dot point

 

[HecticLad]

what about the technology titration question? Never seen this in the syllabus

theres a dot point on there about using computer technologies to measure the pH of acidic substances, i suppose they would expect you to be able to transfer this concept over to titrations because its basically the same thing, didnt you ever do an experiment with a ph probe or something?

 

[Catz]

I dont think we had to mentions a catalyst cause it only asked for temperature and pressure and it was only 6 marks

 

[Khan.Paki]

Was last year's aligning really bad? If it's the same as last year, what shall doth the band 6 mark be?

 

[band6man]

I dont think we had to mentions a catalyst cause it only asked for temperature and pressure and it was only 6 marks

exactly

 

[Bozzin8R]

for barium sulfate modifications one...
i talked about how barium can precipitate with not just sulfate but also phosphate so you had to use lower ph
and also how the presence of lead will precipitate also with chloride so it is better to use nitrate...
does this sound totally off???

There were some more obvious issues with the method. They used 200mL acid rather than like 50mL acid to 150mL water, the acid was dilute when it should have been concentrated, they filtered the dissolved fertiliser before adding Barium Chloride which was wrong, they added the Barium Chloride quickly when they should have added slowly, etc.

 

[Khan.Paki]

I have the multiple sheet paper. Does anyone want me to upload it?

 

[HecticLad]

does that mean i cant get 6/6 because i didnt talk about the catalyst?

id say so, pretty sure the question said something about the conditions used in the haber process with reference to the chart, but doesnt mean you have to talk specifically about the stuff on the chart, i just basically talked about everything I knew for the conditions of haber process cus it was a 6 mark question, theres no way you would be able to write that much just about the info on the graph