Chemistry
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Hello everyone! How do I solve this? Na(s) + 2H2O(l) ⇒ 2NaOH(aq) + H2(g) # of moles: ? XS (=excess) ? ? quantities (m or V at STP): 2.00 g ? ? I know that 23/2=11.5 and that's the number of moles for Na but then I'm lost.. Also can anyone answer this question: "How can you simply make elemental bromine, Br2, from the compound NaBr? I don't understand how to just "know" the answer to these questions.. I thought about putting some chlorine in there to make NaCl but that would make a huge reaction right? Thanks!" Thanks so much for the help
Last reply by John Pappas, -
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Hi everyone, I am currently taking chemistry Hl and I don't really like it. I am not sure whether I should drop it to sl or not. My current subjects are: Math Hl, Chemistry Hl, Physics Hl and English B Hl Arabic Sl, business Sl I am not sure whether I want to do engineering or medicine tho. I can still go to medicine if I keep my chemistry Hl. So is there a big difference? What should I do? Please help Thanks
Last reply by m.k.2015, -
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If any of you are interested in more bonding practice questions, whether it be for your next quiz, or test, exam or final, I found this website, and it has a lot of documents with hundreds of questions. I am sharing because I think many of you might find this useful. There's chem 20, 30, 35 more for hl, but obviously will do for sl, and some university level questions in there. Enjoy, and good luck! Link: http://highschoolchemresources.blogspot.ca/
Last reply by Rahul, -
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Hi! We did a lab, and no we´re supposed to calculate the molar volume of Hydrogen at STP. We did 3 trials. Do you do calculations for each trial, then calculate a mean value out of the three answers? or do start with calcualte a mean value for you three measurments, and then do the calculations on the mean value?? Thank you!
Last reply by Emmi, -
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Hello everyone We have started our internal assessment process in Chemistry Hl, and viscosity is our first assessment. I am really stuck here on coming up with an experiment. The experiment is supposed to be measuring viscosity somehow. For example, the marble test. If any of you have any unique/creative experiments that they could share, I had highly appreciate it. Thank you so much in advance
Last reply by Sandwich, -
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Hi. I am going to have to design an experiment on chemical bonding (topic 4 and 14). I have already looked up on the Internet but all the experiments didn't seem very good. These are some I found: http://www.youtube.com/watch?v=qZW_6Ev0AXc http://www.esciencelabs.com/files/product_pdfs/Sample_Lab_Ionic_and_Covalent_Bonds_1.pdf The first one allows for a somewhat good DCP and CE, but I have serious doubts that my school lab has a conductivity meter. The second one seems too basic. Still, I would like to have a look at other alternatives. Does anyone know anything about other experiments that can be made inside this topic and with somewhat limited apparatus?
Last reply by jaraujo, -
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Last reply by Ryoika, -
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Just want to ask is there a complex ion of sodium and water? I mean aqua-
Last reply by Isaac Wong, -
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Hello Everyone! I need some help picking out what Labs I'd like to do for my lab reports if anyone has any ideas to suggest please do I dont know which ones are the most relevant for IB and usually my results don't turn out that great, so I need to repeat all the IAs are due at the end of the month so the sooner I finish the better ! Please and thank you
Last reply by Eman Salem_121865, -
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Hi everyone, I am very confused about choosing my IA topics, since I was told that it should be chose by me rather than by teacher though I have chosen two. can anyone help me how can I assure that titles I chose will address me properly and will not harm my marks? Thanks,
Last reply by Emmi, -
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SO my Chemistry teacher is new to the IB, no offense but hes bad, he doesent know english well, he doesent know how the IB works, he didnt tell us how to do lab reports and how to prepare for papers (all tests were sh*t, not IB papers) , he doesent know chemistry well and hes full of himself. He grades very subjectively sometimes and has his class pet which he talks most of the classes. We recently gave in a lab report and I used a lab report which got good grades as a way of guide. He gave me a 3 with these marks: DCP: 2,0,0 CE: 1,0,1 Heres the lab report: https://www.dropbox.com/s/5thwkzzi009r1ao/Determining%20an%20enthalpy%20change%20of%20reaction.doc Help please, what…
Last reply by HardHead, -
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elloh! I have a chem ia due on Friday. I'm technically done, but I can't help but think that I'm missing something something in my conclusion :/ I know that for the CE, we have to add any chemical explanation to the experiment - pretty much explain in through chemistry. I don't know what to write about for this! The reaction was a redox titration between Fe and MnO4- . Simple. I got the calculations, uncertainties, weakness/improvements, well, everything else done. My conclusion is written up, but what can I mention in my conclusion that has to do with redox? So far, I have: In response to the original investigation title, Determination of the Percentage of Iron in Iron T…
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Hi guys! I have a homework to give in and I'm stuck on this question: Describe the bonding in iron and explain the electrical conductivity and malleability of the metal. I'm confused and don't understand what they mean by 'bonding in iron'... the way it takes electrons to complete their shell? the angle of bond? I'm very confused... Could you help me? Thanks very much! Note: I'm taking chem SL
Last reply by charco, -
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Hi guys! We are writing our first real lab-raport in Chemistry right now, and we did a lab with determining the molar volume of Hydrogen gas at STP, and we will be assessed on DCP and CE. If anyone has done this lab, do you have any tips what I could write in observations??
Last reply by charco, -
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so we have to so an ia...that could potentialy be a design DCP and CE... i love titrations so i came up with this question How do the classes of alcohol (primary sec. tert.) affect the enthalpy of neutralization of a strong base (NaOH) and strong Acid (HCl)? my question is... is that possible? becuase for what im doing i cant use NaOH i would have to use a primary secondary and tertiary alcohols against their conjugate acid. i just need reassurance that im on the right path... also what are your views on this...is it do-able? does it make sense? any suggestions are welcome too! id really just like to do a titrations because its been forever!
Last reply by charco, -
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What are the differences between the 2 courses? I'm still deciding which HLs to take.
Last reply by IBidiot, -
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Does anyone know of any good IB chemistry experiment relating energy drinks to the human body? Respond ASAP!!! Thanks for the help!!
Last reply by Claire S. Chapuy, -
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which one of these is according to your experience or what you have heard the best study guide for IB Chemistry SL? http://www.amazon.com/IB-Chemistry-diploma-Oxford-Guides/dp/0198390025/ref=sr_1_1?ie=UTF8&qid=1386359865&sr=8-1&keywords=IB+chemistry+guide http://www.amazon.com/Chemistry-IB-Diploma-Study-Guides/dp/0199151423/ref=sr_1_2?ie=UTF8&qid=1386359865&sr=8-2&keywords=IB+chemistry+guide http://www.amazon.com/IB-Chemistry-Edition-diploma-Programme/dp/019839005X/ref=sr_1_3?ie=UTF8&qid=1386359865&sr=8-3&keywords=IB+chemistry+guide I was thinking the first because its the most recent...
Last reply by Dasza, -
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Hey guys! For my chemistry IA, I'm doing a lab about the ideal gas laws. Basically my research question is: To what extent does the relationship between pressure and volume of a sample of CO2 deviate from ideal gas behaviour? So now, my data is going to be deviations from ideal gas behaviour. The problem arises when I consider error analysis. When I'm doing analysis, do I analyze the data I collected i.e. the error from the trend OR do I analyze the error in the error (mindf*ck right there). It is possible to find the error in the error, it's not that difficult (just another equation, out of syllabus though) but I kind of lost sight of what I'm supposed to do. So yeah, sh…
Last reply by Ossih, -
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In dilute solutions, I compare each ion's reduction/oxidation potential with H+ and OH- respectively. However, for concentrated solutions, I keep reading that: anode: Although salt anion may have lower oxidation potential than OH-, because it is more concentrated, it is discharged. cathode: H+ is discharged. Why is it that at the anode you consider the concentration of the ions, but at the cathode, I've only ever heard H+ is discharged in these situations? ;o What would be an IB way of thinking through this? ;3
Last reply by Dasza, -
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Hello, Tomorrow I will have a paper 1 type of test, probably a paper from previous years, whats the best way to prepare? what should I study and concentrate the most on? Regards, Javi
Last reply by rinik, -
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Hi , I'm writing IA, in which I try to determine mass percent of CaCO3 in an eggshell but I have a problem with formulating a hypothesis. My teacher suggested that my hypothesis should be that I assume that there's no CaCO3 in the eggshell, however, I thought that my hypothesis should be supported by literature (which says that there's about 95% CaCO3). Do you think that hypothesis that my teacher suggested is appropriate? I calculated that it is approximately 91% if that can be of any help. Thanks!
Last reply by Madhavi, -
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My teacher just gave us a bunch of past tests and told everyone to solve them. I did everything but since my teacher never let us ask her any question or solve what we don;t understand in class, I have no idea if what I am doing is right or not. Can anyone tell me where I can find the mark scheme for Chemistry HL paper 2 in november 2012? I searched online but they only have november 2011 only =="
Last reply by charco, -
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Ok I have to do this set of math 10 times today and I don't even know if I'm doing the first one right or not. I'm absolutely terrible at this and I would really appreciate it if someone could help me out even on one part! I'm so confused and I don't want to get a zero because of confusion Ok so originally, I had 10 cm3 of 3M HCl, No water, no ethyl ethanoate, 1cm3 glacial ethanoic acid, 4 cm3 ethanol, to do a esterification reaction for our equilibrium topic. 25.80 cm3 of NaOH were titrated against the mixture, and 14.30 cm3 of NaOH were titrated against 3M HCl The questions are as follows 1. How may moles of ethyl ethanoate were there in your original mixture? 2. How m…
Last reply by charco, -
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Hi, I'm in year 1 ib chem, and I am really having difficulty in chemistry, in understanding the concepts and stuff. I go to my teacher but he explains really fast and it gets confusing. I wanted to ask you guys who are really doing well and have any good tips on how you guys prepare for chemistry like in atomic structure and periodicity like we're doing now. I can't get some questions because I don't know how to answer them. Please help, I want to know how all you guys prepare for tests and learn the concept yourself because my teacher is not very helpful in explaining things to me. Any help is really appreciated. Thanks.
Last reply by charco, -
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Hello everyone, I am stuck on this exercise... I don't get how to answer ii) and iii) as we are just given this information.. Could anyone help me? Thanks a lot
Last reply by nuby, -
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Hey guys, How did your chem class celebrate the mole day yesterday?
Last reply by MainRostand, -
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Hey guys!! Does anyone know about how to pick up an IA topic in Chemistry SL? Can it be from preexisting experiments? Can anyone please address me to some guide for that? Thanks,
Last reply by Hooman Tavassolian, -
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We are designing a chemisry experiment that will be asssessed. The teacher gave us the reasearch question of "Investigate the enegry in liquid fuels?", as i am doing research and deciding how i would do this report i have read that that is the main reasearch question but each student should make their own less broad and more focused research question? Does anyone have any idea what i could do? I have no idea. thank you!
Last reply by MainRostand, -
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Okay, I apologise in advance for creating this post which I'm sure has already been asked many times, but is there any particular resource or search term we can use to find the literature values for a Practical? I've been trying to search for the literature value of the time taken for the complete reaction of sodium thiosulfate (Na2S2O3) and hydrochloric acid (HCl) but with no luck whatsoever. As my practical's aim is to determine how the concentration of Na2S2O3 affects the rate of reaction, do I really need to find this literature value to compare with my data? I do understand its importance in the calculation of percentage error, however I'm also slightly confused as …
Last reply by jenicalina, -
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Hi Everyone, I'm currently writing up a DCP/CE IA for Chemistry where we have to calculate the rate of reaction and I had a quick question in regards to the evaluation. There's no theoretical value for the experiment, which means that when I'm writing up my evaluation I'm not sure how to describe the impact of my limitations/weaknesses on the experiment e.g. if they impacted on accuracy,reliability or validity. I don't think I should use the term accuracy because that refers to how close your experimentally calculated value is close to the theoretical value (and we don't have one of those). Does that mean I discuss how the errors I have identified impacted on reliability …
Last reply by Emmi, -
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-Do every past paper - Revise from the Oxford study guide. OK so I am basically worried that if I revise from the study guide that I might do bad on my final exams. I have the course companion and the IBID book and I think that a combination of the study guide past exam papers and classes is all you need For the SL chemistry course. Can anybody who has had enough experience with the study guide tell if I can rely on it for my final exams for revision or will I have to revise the books I have. I got a 7 on my paper 1 mock (100% didn't miss a question ) and a 6 on my on my paper 2 mock( didn't revise about emission spectra and that cost me a 7) and now 3 months later I feel…
Last reply by Dax, -
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Aim: The aim is to determine the concentrations of two acids and consequently the enthalpy of neutralisation for each reaction. Chemicals: NaOH 1M (standardised) HCl 2.0 M CH3COOH 2.0 M So the formulae would be: NaOH + HCl --> NaCl + H20 NaOH + CH3COOH --> NaCH3COO + H2O So basically, I added 50 cm3 of NaOH to a polystyrene cup and then put the HCl in the burette. I added successive portions of 5cm3 and saw the temperature until I reached 50cm3 of HCl Did the same for CH3COOH. Now we have to find the enthalpy of neutralisation values Questions to answer The enthalpy of neutralisation of a strong acid/base is constant. Why is the value constant? Experimental resu…
Last reply by adeljithu, -
I'm having a bit of trouble writing my conclusion. We haven't gotten to organics in class yet, but I have read the chapter in the book, yet I can't properly explain the effect. Boiling point is highest in primary alcohols and lowest in tertiary alcohols. I explained this by the symmetry of the chain and it's length. However, I can't find a relation between the position of -OH and the boiling point. Thank you so much for your help
Last reply by adeljithu, -
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Hi Everyone, I have an IA at the moment (about the rate of reaction for the reaction between sodium thiosulfate and hydrochloric acid) and I'm trying to write up the evaluation. However in the evaluation our teacher said we need to identify whether the weaknesses we identify are systematic or random errors and I'm really confused because I'm not 100% sure about what exactly systematic and random errors are. Here's a simplified list of the weaknesses I've identified for my particular prac and I was wondering if somebody could please just let me know if I have correctly identified the errors as either systematic or random : - Difficult to add the reactants together and sta…
Last reply by panos, -
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I study so hard for chemistry. I literally lose sleep over it. I review every new topic we learn on the same night. I use the Pearson's baccalaureate text book (the school gave us the John Green and Sadru Damji, which is pretty useless) and I literally memorize it. Yet whenever we have a test or exam im lucky if I get a 5. Our teacher is horrible. She rushes through the syllabus without stopping for people. She just doesn't care if we do badly. I know we should be the ones helping ourselves but thats what im trying to do. The IB always uses unfamiliar wording and new situations not explored the textbook and I panic in the test when I see some of them. my question is for…
Last reply by Emmi, -
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In order for magnesium to react with oxygen, is there always a need for activation energy?
Last reply by MWL, -
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Hey guys, i was just wondering if Chem HL is that hard - i have 3 topics left (Acids and Bases, Redox and organic chem). How hard are these topics relative to the prior Hl topics. Which one of the HL topics do you guys find the hardest in chemistry? Also how hard is it to achieve a 7 in Chem HL if you are bad at lab reports? Thank you guys in advance for your responses
Last reply by milk, -
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I have to do an HL IA on "Investigate a factor affecting rate". Can somebody please help me with ideas to use something worth of HL such as an interesting reaction and a way to measure the rate? Maybe the gas released, measurer, or some other method? Any ideas Appreciated.
Last reply by by.andrew, -
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So I'm doing a lab and I'm stuck on this one question, "Present evidence for the existence of orbitals.". So I am provided with this table of elements all the way to fermium with covalent radii, ionic radii, atomization energy, the first, second, third, and fourth ionization energy, bond energy for the element to fluorine, to hydrogen, to oxygen, and to itself. It's due tomorrow so I need an answer or hints fast. Attached is the data which I"m supposed to use to support my explanation. Elements.xlsx
Last reply by by.andrew, -
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- 586 views
Hi, I was wondering to do Chemistry SL do you need to know much before the IB, as I was considering this subject and wanted to now, how vigorous it is, and whether you require much previous knowledge from it as I didn't do any gcse's due to the fact that I lived in Australia, and we only had normal end of year exams. Thanks!
Last reply by guns 'n' roses, -
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I am currently forecasting for my classes next year, and I am having difficulty deciding whether or not I should I take IB Chemistry SL, due to fear of it being incredibly difficult. From upperclassmen, I have heard stories of grueling study hours and extremely rigorous exams. To place this fear into perspective, I would consider myself to be a scientifically/mathematically inclined student. I will also be taking either IB Math SL or HL. Thoughts? Opinions?
Last reply by mm8888, -
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In the writing of my Extended Essay, I'm analysing the data of a bunch of runs I did of a reaction involving ammonium nitrate and water. I made the temperature graphs in Pasco DataStudio (which also happens to be poorly made and a huge pain in the ass to use), and compensated for the imperfect calorimeter and reaction by extrapolating the rate of cooling and finding the intersection between the line and the time the nitrate was added. Which is all well and good, but out of the three uncertainties I'd need to take into account (slope, init time, y-intercept), I'm missing two. Pasco DataStudio doesn't seem to have a function for finding the slope and y-intercept uncertainty…
Last reply by by.andrew, -
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Hi, This is my first design lab, and I cannot figure out any research question in rates of reaction. Can you please give me examples of Research Questions with which i can work on (excluding clock reactions and design labs including HCl with another base) and something that is not very difficult as well? :-P
Last reply by MainRostand, -
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OMG! My chem teacher is always obssessive about having perfect tables? Any tips on how to make perfect data tables for the IB? I just started IB by the way in Grade 11. Thanks
Last reply by by.andrew, -
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Can you'll please help me and give me a suitable research question for the design lab on rates of reaction? Not one which is too easy though.
Last reply by IBKID4lyf, -
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Hello, I was wondering what people have done as a rates of reaction IA? I'm still undecided on my choice, and would like to see what others have chosen! Thanks
Last reply by MainRostand, -
Chemistry HL or Biology HL
by Guest Sophia Schlaak- 10 replies
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hey, i don´t know whether to take Chemistry HL oder Biology HL. In my german ib programme I do a double diploma and that is the reason why I have to take literature HL and geography HL. I really really like chemistry and I understand everything but my exams are not as good as my biology exams. Because I do the IB programme additionally it doesn´t matter how many points i get. Therefore, i´d like not to have so much extra work. So, should I take Chem HL although i´m not as good as i am in biology? or shall I take biology HL because it´s easier to understand and not as challenging as chemistry? :/ Thank you in anticipation
Last reply by MainRostand, -
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I have trouble finding in Chem and most of the other subject areas the learning outcomes answered in a complete, concise and up to date manner. The companion text books for the courses are good but too wordy. Assuming we can't just buy all the current study guides, what are some good online resources you know of? It would essentially be the same sort of study notes we'd put on cue cards used to cram for YR 2 exams It would be helpful if anyone wanted to fill out and complete some of the Wikibooks guides, they provide a nice template but are a little outdated and lacking in information. Any help would be greatly appreciated! http://en.wikibooks.org/wiki/International_Bacc…
Last reply by ~Lc~,
