Chemistry 3/4 2013 Thread

[Edward21]

Hey, has anyone done the outcome 2 sac on the methyl salicylate (deep heat)? What type of questions could be asked besides drawing the structural formula of the ester and the alcohol (methanol) and acid (salicyclic acid) ?

[Stick]

^ I might ask the same about the aspirin SAC. It seems that the only definite questions will relate to percentage yield and the structure of the aspirin molecule. Anything else?

[hardworker]

We did our sac for organic chem on Monday it was based on enzyme and starch which was really boring considering the experiment didnt work properly for most people. By the way do any of you guys have a mid year exam for chem has a SAC.

[Alwin]

^ I might ask the same about the aspirin SAC. It seems that the only definite questions will relate to percentage yield and the structure of the aspirin molecule. Anything else?

AHA.. HA.. HA.. no >_>

My chem teacher combined sac 1 & 2 into 1 massive 165 min writeup. It was just 2 thick booklets, 1 for each sac and it was all questions. No where did it ask to even write out aim, observations, etc just questions and questions and then write a page long conclusion. Needless to say, no one in our chem cohort finished it. Me and 2 others came close tho, but no cigar.

The things he asked us included:

     > Write full balanced equations showing states with structural and molecular formula
     > Calculations based on data supplied by the teacher for percentage yeild, etc
     > Calculations based on our own experimental data
     > Explain possible errors that resulted in the difference in percentage yeild
     > How to prove our sample was pure
     > How to use GC find the percentage yeild
     > If not all the salicylic acid had reacted, how to use UV-Vis to determine amount un-reacted
     > After finding how much salicylic acid unreacted, how to adjust percentage yeild
     > How to prove sulfuric acid is a catalyst
     > Why did we use acetic anhydride not ethanoic acid
     > Effects of not cooling the mixture after sulfuric acid added
     > Safety precautions and rish management
     > Account for loss of Aspirin ie why not 100% yeild
     > Explain in simple terms how we crystalised out the Aspirin
     > Suggest why the Buchner funnel is inefficient
     > Ways to make the experiment more efficient
     > Ways to make the percentage yeild more accurate
     > If glassware had not been correctly rinsed, discus effects on accuracy
     > Spectrum on Aspirin and asked specific questions
     > Aspirin can also be obtained from Oil of Wintergreen (Ch 14 of textbook)
     > Discuss how Aspirin can be obtained from Old of Wintergreen
     > Draw the reaction pathway
     > And that's just sac 2 stuff, there was a hell of a lot more on sac 1 ha.. ha..

Well, I guess that list should help you get started and if you were wondering, I only had my sac yesterday so that's how I can remember all this.. not looking forward to the results tho

EDIT 1: Thought of a couple more dot points to add in, in case there originally wasn't enough
EDIT 2: Teacher was trying to emulate an end of year exam situation hence the length of the thing. He also added in a page of BONUS questions, just in case someone managed to finish both booklets in time. Some people were only lucky enough to finish the first booklet.

[Mr Keshy]

AHA.. HA.. HA.. no >_>

My chem teacher combined sac 1 & 2 into 1 massive 165 min writeup. It was just 2 thick booklets, 1 for each sac and it was all questions. No where did it ask to even write out aim, observations, etc just questions and questions and then write a page long conclusion. Needless to say, no one in our chem cohort finished it. Me and 2 others came close tho, but no cigar.

The things he asked us included:

     > Write full balanced equations showing states with structural and molecular formula
     > Calculations based on data supplied by the teacher for percentage yeild, etc
     > Calculations based on our own experimental data
     > Explain possible errors that resulted in the difference in percentage yeild
     > How to prove our sample was pure
     > How to use GC find the percentage yeild
     > If not all the salicylic acid had reacted, how to use UV-Vis to determine amount un-reacted
     > After finding how much salicylic acid unreacted, how to adjust percentage yeild
     > How to prove sulfuric acid is a catalyst
     > Effects of not cooling the mixture after sulfuric acid added
     > Safety precautions
     > Account for loss of Aspirin ie why not 100% yeild
     > Suggest why the Buchner funnel is inefficient
     > If glassware had not been correctly rinsed, discus effects on accuracy
     > Spectrum on Aspirin and asked specific questions
     > And that's just sac 2 stuff, there was a hell of a lot more on sac 1 ha.. ha..

Well, I guess that list should help you get started and if you were wondering, I only had my sac yesterday so that's how I can remember all this.. not looking forward to the results tho

What. The! What was he thinking haha!

[Jeggz]

AHA.. HA.. HA.. no >_>

My chem teacher combined sac 1 & 2 into 1 massive 165 min writeup. It was just 2 thick booklets, 1 for each sac and it was all questions. No where did it ask to even write out aim, observations, etc just questions and questions and then write a page long conclusion. Needless to say, no one in our chem cohort finished it. Me and 2 others came close tho, but no cigar.

The things he asked us included:

     > Write full balanced equations showing states with structural and molecular formula
     > Calculations based on data supplied by the teacher for percentage yeild, etc
     > Calculations based on our own experimental data
     > Explain possible errors that resulted in the difference in percentage yeild
     > How to prove our sample was pure
     > How to use GC find the percentage yeild
     > If not all the salicylic acid had reacted, how to use UV-Vis to determine amount un-reacted
     > After finding how much salicylic acid unreacted, how to adjust percentage yeild
     > How to prove sulfuric acid is a catalyst
     > Why did we use acetic anhydride not ethanoic acid
     > Effects of not cooling the mixture after sulfuric acid added
     > Safety precautions and rish management
     > Account for loss of Aspirin ie why not 100% yeild
     > Explain in simple terms how we crystalised out the Aspirin
     > Suggest why the Buchner funnel is inefficient
     > Ways to make the experiment more efficient
     > Ways to make the percentage yeild more accurate
     > If glassware had not been correctly rinsed, discus effects on accuracy
     > Spectrum on Aspirin and asked specific questions
     > Aspirin can also be obtained from Oil of Wintergreen (Ch 14 of textbook)
     > Discuss how Aspirin can be obtained from Old of Wintergreen
     > Draw the reaction pathway
     > And that's just sac 2 stuff, there was a hell of a lot more on sac 1 ha.. ha..

Well, I guess that list should help you get started and if you were wondering, I only had my sac yesterday so that's how I can remember all this.. not looking forward to the results tho

EDIT: Thought of a couple more dot points to add in, in case there originally wasn't enough

Legend! Thanks for that mate - will definitely come in hand for my SAC next week 

[teletubbies_95]

AHA.. HA.. HA.. no >_>

My chem teacher combined sac 1 & 2 into 1 massive 165 min writeup. It was just 2 thick booklets, 1 for each sac and it was all questions. No where did it ask to even write out aim, observations, etc just questions and questions and then write a page long conclusion. Needless to say, no one in our chem cohort finished it. Me and 2 others came close tho, but no cigar.

The things he asked us included:

     > Write full balanced equations showing states with structural and molecular formula
     > Calculations based on data supplied by the teacher for percentage yeild, etc
     > Calculations based on our own experimental data
     > Explain possible errors that resulted in the difference in percentage yeild
     > How to prove our sample was pure
     > How to use GC find the percentage yeild
     > If not all the salicylic acid had reacted, how to use UV-Vis to determine amount un-reacted
     > After finding how much salicylic acid unreacted, how to adjust percentage yeild
     > How to prove sulfuric acid is a catalyst
     > Why did we use acetic anhydride not ethanoic acid
     > Effects of not cooling the mixture after sulfuric acid added
     > Safety precautions and rish management
     > Account for loss of Aspirin ie why not 100% yeild
     > Explain in simple terms how we crystalised out the Aspirin
     > Suggest why the Buchner funnel is inefficient
     > Ways to make the experiment more efficient
     > Ways to make the percentage yeild more accurate
     > If glassware had not been correctly rinsed, discus effects on accuracy
     > Spectrum on Aspirin and asked specific questions
     > Aspirin can also be obtained from Oil of Wintergreen (Ch 14 of textbook)
     > Discuss how Aspirin can be obtained from Old of Wintergreen
     > Draw the reaction pathway
     > And that's just sac 2 stuff, there was a hell of a lot more on sac 1 ha.. ha..

Well, I guess that list should help you get started and if you were wondering, I only had my sac yesterday so that's how I can remember all this.. not looking forward to the results tho

EDIT 1: Thought of a couple more dot points to add in, in case there originally wasn't enough
EDIT 2: Teacher was trying to emulate an end of year exam situation hence the length of the thing. He also added in a page of BONUS questions, just in case someone managed to finish both booklets in time. Some people were only lucky enough to finish the first booklet.

^^ Now that's what I call crazy! :O
I had my organic pathways sac yesterday. There was one question that everyone in the cohort was iffy about , that I just needed to clarify. It was a 3 mark question asking if you were given like 1- butanol and 2- butanol, what test would you use to differentiate between them?
My answer was to test using an oxidisation reaction using KMnO4- and H2SO4 ( for H+ ions) and use litmus paper , to check if it is red in colour or not, as only primary alcohols ( 1-butanol) undergo oxidisation (redox) reactions to make carboxylic acids( thus using the litmus paper).
Is that right?

Thank you!

[Stick]

AHA.. HA.. HA.. no >_>

My chem teacher combined sac 1 & 2 into 1 massive 165 min writeup. It was just 2 thick booklets, 1 for each sac and it was all questions. No where did it ask to even write out aim, observations, etc just questions and questions and then write a page long conclusion. Needless to say, no one in our chem cohort finished it. Me and 2 others came close tho, but no cigar.

The things he asked us included:

     > Write full balanced equations showing states with structural and molecular formula
     > Calculations based on data supplied by the teacher for percentage yeild, etc
     > Calculations based on our own experimental data
     > Explain possible errors that resulted in the difference in percentage yeild
     > How to prove our sample was pure
     > How to use GC find the percentage yeild
     > If not all the salicylic acid had reacted, how to use UV-Vis to determine amount un-reacted
     > After finding how much salicylic acid unreacted, how to adjust percentage yeild
     > How to prove sulfuric acid is a catalyst
     > Why did we use acetic anhydride not ethanoic acid
     > Effects of not cooling the mixture after sulfuric acid added
     > Safety precautions and rish management
     > Account for loss of Aspirin ie why not 100% yeild
     > Explain in simple terms how we crystalised out the Aspirin
     > Suggest why the Buchner funnel is inefficient
     > Ways to make the experiment more efficient
     > Ways to make the percentage yeild more accurate
     > If glassware had not been correctly rinsed, discus effects on accuracy
     > Spectrum on Aspirin and asked specific questions
     > Aspirin can also be obtained from Oil of Wintergreen (Ch 14 of textbook)
     > Discuss how Aspirin can be obtained from Old of Wintergreen
     > Draw the reaction pathway
     > And that's just sac 2 stuff, there was a hell of a lot more on sac 1 ha.. ha..

Well, I guess that list should help you get started and if you were wondering, I only had my sac yesterday so that's how I can remember all this.. not looking forward to the results tho

EDIT 1: Thought of a couple more dot points to add in, in case there originally wasn't enough
EDIT 2: Teacher was trying to emulate an end of year exam situation hence the length of the thing. He also added in a page of BONUS questions, just in case someone managed to finish both booklets in time. Some people were only lucky enough to finish the first booklet.

THAT'S HORRIBLE!!! I feel so sorry for you. I really hope it all works out in the end.

I definitely don't think everything you've put there will be covered, given my write-up will only be 55 minutes. Nonetheless, thanks, because I'm assuming that everything that will be covered in my SAC is in that list.

[Stick]

How important are states in reaction pathways? Sometimes they're included, sometimes they're not, and often it's not easy to deduce what the states are.

[pi]

Try and include all states that you can is the general rule of thumb.

[Alwin]

How important are states in reaction pathways? Sometimes they're included, sometimes they're not, and often it's not easy to deduce what the states are.

From the 2012 Chemistry Exam:

Instructions for Section B
Answer all questions in the spaces provided. Write using black or blue pen.
To obtain full marks for your responses you should

• give simplified answers with an appropriate number of signifi cant fi gures to all numerical questions;
  unsimplified answers will not be given full marks.
• show all working in your answers to numerical questions. No credit will be given for an incorrect answer
  unless it is accompanied by details of the working.
• make sure chemical equations are balanced and that the formulas for individual substances include an
  indication of state; for example, H₂(g); NaCl(s).

I would say that states are just a bit important

[Jeggz]

Hmm but as Stick said they're not always easy to deduce, so how are you meant to figure them out when they're not as obvious?

[thushan]

VCAA generally wont ask you to write equations where states are hard to deduce; this would be most organic reactions (such as substitutions and that).

[Alwin]

Hmm but as Stick said they're not always easy to deduce, so how are you meant to figure them out when they're not as obvious?

Either memorise (a bit tedious but can be done) or use common sense.

eg, a hydrocarbon is burnt in air. you don't know what hydrocarbon it is, but you know it is most likely a gas (or liquid possibly) but definitely not aqueous - since then you would be burning in water too.
Also, some reactions are homogeneous chemical reactions so that makes states much easier.

[Stick]

VCAA generally wont ask you to write equations where states are hard to deduce; this would be most organic reactions (such as substitutions and that).

This was what I was thinking, since the StudyOn answers (which are just copy-pasted VCAA solutions) don't seem to include them very often. It's not even covered in the textbook very much. I may ask my Chemistry teacher to make sure though.