Chemistry HL/SL help

[ShootingStar16]

I am really stressed out about chem right now.. I got my first quiz back and I got 79% just cuz I used full electron configuration first and then converted it to condensed electron configuration. I put boxes around the final answers but my teacher still marked it wrong cuz apparently, I'm supposed to only put one final answer there. I know that I can retake the written response portion of the quiz but it still really upsets me I also got my graph back and I got 3/5. I can redo that too but I'm scared I'll fail Chemistry SL.  

[Sofia.]

I am really stressed out about chem right now.. I got my first quiz back and I got 79% just cuz I used full electron configuration first and then converted it to condensed electron configuration. I put boxes around the final answers but my teacher still marked it wrong cuz apparently, I'm supposed to only put one final answer there. I know that I can retake the written response portion of the quiz but it still really upsets me I also got my graph back and I got 3/5. I can redo that too but I'm scared I'll fail Chemistry SL.  

 

Don't be! You have just started the course, and 79% on a test in far from failing. It's probably a low 7/high 6, which is an amazing grade! If you are used to getting close to 100% of tests, starting IB can often be a bit of a shock, but that is completely normal. You're not supposed to get a 100% on a test - they're not designed that way. That's why the grade boundaries are the way they are. You can get a 7 by scoring around 80% in most courses! So, don't be scared of failing chemistry - you're going to do great! 

[ShootingStar16]

wait i actually got 70% cuz our teacher was calculating the weighted average.. multiple choice was worth 70% and i got full marks on it. I failed the written response I did get all the right answers, but it was the way I answered my teacher is marking like this because he said this is how picky IB is and if the teachers mark too easy, the IB examiners drop everyone's marks like 20%..

Edited September 26, 2014 by ShootingStar16

[Sofya]

Hello!

Please, help me( I don't understand what EXACTLY I'm asked to do in the following tasks:

 

1)Draw a labelled diagram to show the electron transition between energy levels 

in a hydrogen atom that are responsible for the series of lines seen in the visible 

emission spectrum. Draw a line to show the first ionization energy. 

Do I need to show the lines, responsible for visible emissions? And what about the first ionisation energy? How should I show it on the diagram?

 

2)Draw a labelled diagram of the visible line spectrum of hydrogen. Identify the 

position of the infrared and ultraviolet parts of the spectrum. 

I need to draw the transition to n=1, n=2 , n=3 and write which is UV, which us Infra-red and which is visible?

 

Thank you in advance!

[Jenine]

I am currently doing organic chemistry and is confused about Sn1 and Sn2 reactions.

I can't really distinguish between them and they are confusing me as hell. Apparently Sn1 is a one step reaction so that's why it's called Sn1 but it has three stages such as the picture attached. But what exactly is Sn1 and Sn2???

 

Please help me.

[Vioh]

I am currently doing organic chemistry and is confused about Sn1 and Sn2 reactions.

I can't really distinguish between them and they are confusing me as hell. Apparently Sn1 is a one step reaction so that's why it's called Sn1 but it has three stages such as the picture attached. But what exactly is Sn1 and Sn2???

 

Please help me.

 

In halogenoalkanes, the bond between the carbon-atom & the halogen is polar (with the carbon-atom being slightly more positive compare to the halogen); thus the region around the carbon-atom is called electron deficient area, which can be easily attacked by a negatively-charged nucleophile. Based on this fact, scientists use a nucleophile to attack this ‘electron-deficient area’ of the carbon-atom to replace the halogens inside the compound; all of this attack-and-replacing business is the so-called “nucleophilic substitution reaction” (and hence the symbol 'Sn')

 

The rest of the stuff down here is taken from the extended version of my own study guide:

 

 

If you find my notes hard to follow, then I recommend you to watch this playlist which contains 4 videos from Khan Academy (https://www.youtube.com/watch?v=nwULacjb78c&list=PLy1Tm-83CHid8KU8hATGjxMPz6F3QBVjO&index=1)

Cheers!

Edited November 3, 2014 by Vioh

[Msj Chem]

I am currently doing organic chemistry and is confused about Sn1 and Sn2 reactions.

I can't really distinguish between them and they are confusing me as hell. Apparently Sn1 is a one step reaction so that's why it's called Sn1 but it has three stages such as the picture attached. But what exactly is Sn1 and Sn2???

Please help me.

SN1 stands for substitution nucleophilic unimolecular, it is a two step mechanism and the rate determining step is unimolecular (it depends on the concentration of the halogenoalkane only).

SN2 stands for substitution nucleophilic bimolecular, it is a one step mechanism and the rate determining step is bimolecular( depends on the concentration of the halogenoalkane and the nucleophile).

Check out my videos on these mechanisms here (towards the bottom the page).

http://www.msjchem.com/topic-10-organic-chemistry.html

Edited November 3, 2014 by Msj Chem

[Jenine]

 

I am currently doing organic chemistry and is confused about Sn1 and Sn2 reactions.

I can't really distinguish between them and they are confusing me as hell. Apparently Sn1 is a one step reaction so that's why it's called Sn1 but it has three stages such as the picture attached. But what exactly is Sn1 and Sn2???

 

Please help me.

 

In halogenoalkanes, the bond between the carbon-atom & the halogen is polar (with the carbon-atom being slightly more positive compare to the halogen); thus the region around the carbon-atom is called electron deficient area, which can be easily attacked by a negatively-charged nucleophile. Based on this fact, scientists use a nucleophile to attack this ‘electron-deficient area’ of the carbon-atom to replace the halogens inside the compound; all of this attack-and-replacing business is the so-called “nucleophilic substitution reaction†(and hence the symbol 'Sn')

 

The rest of the stuff down here is taken from the extended version of my own study guide:

 

Untitled.png

 

If you find my notes hard to follow, then I recommend you to watch this playlist which contains 4 videos from Khan Academy (https://www.youtube.com/watch?v=nwULacjb78c&list=PLy1Tm-83CHid8KU8hATGjxMPz6F3QBVjO&index=1)

Cheers!

 

 

Thank you!

 

I am currently doing organic chemistry and is confused about Sn1 and Sn2 reactions.

I can't really distinguish between them and they are confusing me as hell. Apparently Sn1 is a one step reaction so that's why it's called Sn1 but it has three stages such as the picture attached. But what exactly is Sn1 and Sn2???

Please help me.

SN1 stands for substitution nucleophilic unimolecular, it is a two step mechanism and the rate determining step is unimolecular (it depends on the concentration of the halogenoalkane only).

SN2 stands for substitution nucleophilic bimolecular, it is a one step mechanism and the rate determining step is bimolecular( depends on the concentration of the halogenoalkane and the nucleophile).

Check out my videos on these mechanisms here (towards the bottom the page).

http://www.msjchem.com/topic-10-organic-chemistry.html

 

 

 

Thank you!

[Msj Chem]

Hello!

Please, help me( I don't understand what EXACTLY I'm asked to do in the following tasks:

 

1)Draw a labelled diagram to show the electron transition between energy levels 

in a hydrogen atom that are responsible for the series of lines seen in the visible 

emission spectrum. Draw a line to show the first ionization energy. 

Do I need to show the lines, responsible for visible emissions? And what about the first ionisation energy? How should I show it on the diagram?

 

2)Draw a labelled diagram of the visible line spectrum of hydrogen. Identify the 

position of the infrared and ultraviolet parts of the spectrum. 

I need to draw the transition to n=1, n=2 , n=3 and write which is UV, which us Infra-red and which is visible?

 

Thank you in advance!

This video should help:

http://youtu.be/jGqjRjcrqhI

[Sofya]

I am doing a lab report and I also need to figure out what element X is. 
Please, if someone sees the mistake I make, help me! I really don't understand what I am doing wrong. 
Thank you in advance!

 

Hello!
Please, help me( I don't understand what EXACTLY I'm asked to do in the following tasks:
 
1)Draw a labelled diagram to show the electron transition between energy levels 
in a hydrogen atom that are responsible for the series of lines seen in the visible 
emission spectrum. Draw a line to show the first ionization energy. 
Do I need to show the lines, responsible for visible emissions? And what about the first ionisation energy? How should I show it on the diagram?
 
2)Draw a labelled diagram of the visible line spectrum of hydrogen. Identify the 
position of the infrared and ultraviolet parts of the spectrum. 
I need to draw the transition to n=1, n=2 , n=3 and write which is UV, which us Infra-red and which is visible?
 
Thank you in advance!

This video should help:
http://youtu.be/jGqjRjcrqhI

 

thank you!!!!

Find the Metal.docx

[Julio17]

Hi, I think my teacher is being too radical regarding the chem IA's.. please help me as none of my classmates are getting good grades...

 

My teacher makes us do all the Design, DCP, CE in CLASS, in test conditions, when we finish the experiments, we have to sit down and do the DCP, without asking him or any of our classmates, and without looking things up on the internet. He provides us with a sheet of paper and everything has to be handwritten. 

So a week before the Lab is conducted he explains the procedure to us and answers questions, and we have to study the topic in question so that we know how to do the calculations... 

There is no draft or feedback, what we produce in those 45 minutes under test conditions is our final 'report'...

 

His justification for this is that this is the only way that he can ensure that we don't copy from our friends or from the internet, and that he is following IB regulations, if he let us take it home there is no way for him to prove to the IB that what we produce is what we actually know...

 

Isn't this wrong or too radical? What do other schools do?

[Msj Chem]

It depends what you are 'looking up on the internet' - the work that you submit must be all your own. Your teacher's way of doing it is ensuring that it is all your own work. It is not specified by the IB that the chemistry internal assessment must be completed under test conditions. It is allowed for teachers to give (limited) feedback on one draft of your lab report.

If you are concerned, then you could try talking to the DP coordinator at your school.

Edited December 14, 2014 by Msj Chem

[Julio17]

It depends what you are 'looking up on the internet' - the work that you submit must be all your own. Your teacher's way of doing it is ensuring that it is all your own work. It is not specified by the IB that the chemistry internal assessment must be completed under test conditions. It is allowed for teachers to give (limited) feedback on one draft of your lab report.

If you are concerned, then you could try talking to the DP coordinator at your school.

Thanks for your attention.

Yes the work is all my own... What I would look up on the internet or in my textbook is, for example, how to calculate theoretical yield, or how to find moles based on percentage.. not the actual results... 

So lets say that I request to hand in a draft for him to give me limited feedback, is he required to do so ?

[Msj Chem]

The chemistry guides states that teachers are allowed to give limited feedback on one draft of your lab reports. It is not a requirement that teachers do so, but it allows students to improve their work for the final draft. The type of feedback I give is things like significant figures or make sure to put units and uncertainties in the results table, areas that students often make mistakes in. How many assessed labs are you doing for your internal assessment?

[ShootingStar16]

I REALLY REALLY NEED HELP WITH CHEM RIGHT NOW

 

ok so the equation: C₃H_8(g)+5O_2(g)--> 3CO_2(g)+4H₂O(g) 

 

The question asks to predict the number of moles of oxygen gas used in the reaction when there's 8.0 mol of propane before the reaction and 3.5 mol of methane after the reaction. Is that a typo? and what kind of work do I need to show if it says 'predict'? 

Edited January 9, 2015 by ShootingStar16

[pakarang]

Which chemistry should i take for my IB, if i wanted to do the pre medical  program i already have Bio HL

[Baller97]

Which chemistry should i take for my IB, if i wanted to do the pre medical  program i already have Bio HL

Most universities would require both Chemistry and Biology at HL for medicine.

[IbTrojan]

Well I plan on doing pre-medical and I took SL chemistry, but it depends on the university. Check to see what qualifications they want (if they require both HL courses or just that you take the two courses and do well in them)

[kristinemjs]

Hi! I need some help with my Chem IA, and I would be very happy if you could take a look at my post:

 

http://www.ibsurvival.com/topic/33704-internal-assessment-topic-for-chemistry-hl/#entry236271

 

Thanks!   

[samuelmwase]

I am gonna be a 10 th grader in a few days and aiming to keep my MYP chem grade at 7 as I am interested in takin Chem. Hl in Dp.....

I knw that our main topic in grade 10 will be stoichiometry...Can anyone pls suggest the best way to start learning stoichimetry as I wanna be ahead by the time we begin school. What strategies can I use to understand and hopefully master some stoichiometry before school opens?