BoS trials Maths and Chemistry 2020 (1 Viewer)

[idkkdi]

Pending someone giving that, feel free to name a handful of specific questions you want to know the answer to and we can provide a brief outline of the solution.

Just a question, are people able to get their own papers which are marked back?

 

[Trebla]

Just a question, are people able to get their own papers which are marked back?

It should be possible. The only thing is that the questions are spread out between multiple people marking, so somehow have to coordinate collecting it from each person...

 

[Trebla]

Just a reminder the Chemistry exam is on tomorrow afternoon at Chatswood!

On the day, you will be required to provide your mobile details (for potential contact tracing purposes) and be subject to a temperature check. Please speak to reception and you will be directed to the Jeff Bezos/Sheryl Sandberg seminar room.

Please respect and observe distancing rules. Mask wearing is highly encouraged (though not required). If you are feeling unwell or have been directed to isolate by NSW Health, please stay at home and let me know that you are unable to attend.

Also, we still have room for a small number of last minute registrations. So if you would like to attend, please let me know.

Look forward to seeing you there!

 

[jazz519]

See you all tomorrow!

 

[Paradoxica]

Just a question, are people able to get their own papers which are marked back?

could also scan it not sure how much easier that would be

e: on second thought it's not terribly inconvenient to meet up at parramatta to arrange it

 

[D3spair]

Is it possible if the chemistry can be uploaded? thanks

 

[Drdusk]

How’d you all find the chem exam?

 

[jazz519]

Is it possible if the chemistry can be uploaded? thanks

The paper will be uploaded today after a typo change

 

[Trebla]

Thanks to everyone that attended today for the Chemistry BoS trial exams! This was our first ever year doing trial exams for this subject so hopefully you found the paper to be useful and interesting!

Massive thanks to jazz519 for writing the paper and Drdusk for coming to help supervise the exam day. Also, thanks to Talent100 for giving us the venue and iStudy for organising it.

Please find the paper attached. There may still be typos, so feel free to call them out for us to consider.

Just like with Maths, we will be marking the papers and putting solutions together. We will aim to get them out in due course before your HSC exam. We would appreciate your patience as this will take time to get through and write up.

If you want any hints/guides/answers to specific questions right now or just want to discuss the paper, please post in this thread. Were there any questions you particularly liked or want to know how to do?

 

[laraknight]

Hi, thanks so much for organising!

If it were possible to get solutions for question 35 of the chemistry paper then that would be great thanks!!

 

[jazz519]

Hi, thanks so much for organising!

If it were possible to get solutions for question 35 of the chemistry paper then that would be great thanks!!

Just some hints:

E is a tertiary alcohol (2-methylbutan-2-ol) as it is not oxidising by the oxidising agent

C is 2-bromo-2-methylbutane as it makes E through a substitution

A is an alkene. It is 2-methylbut-1-ene. It must be the but-1-ene bit because it needs to make a primary alcohol to make the carboxylic acid in compound F

B is 1-bromo-2-methylbutane. Other isomer of the addition reaction of HBr

D is 2-methylbutan-1-ol

F is a carboxylic acid

G is a sodium salt

H and I are made because it can react two ways either alcohol + carboxylic acid = ester

or amine + carboxylic acid = amine

 

[jazz519]

Full solutions will be up sometime on the weekend / early next week after I've marked the papers

 

[ikindawannasleep]

Heyy could you also put the chem one up when you can ?

 

[Drdusk]

Heyy could you also put the chem one up when you can ?

It’s already up 5 posts above

 

[ikindawannasleep]

It’s already up 5 posts above

thxx

 

[Volcanis]

How do you q11 c) of the 3u paper?

 

[Trebla]

How do you q11 c) of the 3u paper?

When you perform the substitution, your integrand should look very similar to a standard normal probability density function. You can then use some of its properties to get the answer.

 

[Paradoxica]

Remark: For the Induction in MX2 13 c i, many students tried to differentiate the recurrence and arrive at the given definition of the Hₙ(x) Polynomials. While this was not an invalid way of doing the problem, it made your life 100 times harder, as manipulating so many expressions at once was just a pain to write out (As I noticed when marking). Many students simply gave up after realising the mess they had gotten themselves into. The easier (and arguably technically correct) way of doing the problem was to differentiate the definition of Hₙ(x) and almost instantly arrive at the recurrence.

 

[Trebla]

A useful exam tip I wanted to share after marking Q12 for Maths Ext2.

I'm seeing a lot of students go ahead and directly derive the displacement equations of simple harmonic motion by integration in Q12b)i). Whilst it is useful to know how to do that, you actually do NOT need to waste time/effort in deriving these (unless the question specifically asks you to).

In fact, the displacement equation is given to you in the reference sheet under the heading "Mechanics". You are therefore allowed to simply quote the general solution off the reference sheet (e.g. x = acos (nt + α) + c) and then work out the specific solution from the initial conditions provided in the question. This is far quicker and less complicated than the integration approach (which requires carefully choosing either the positive or negative velocity after square rooting, depending on the situation).

 

[Drdusk]

Hey, is it possible to send the Chemistry paper since it has already been done? or just link it to me if it has been posted elsewhere cheers C:

It's like 12 posts up....