Chemistry
For Chemistry Discussions
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I have updated my website with syllabus information for the new syllabus and new videos. All new syllabus videos have practice worksheets. My old syllabus videos (including options B, E and F) can still be found here (option videos have practice exam questions). http://www.msjchem.com Example from topic 1 of new syllabus: http://www.msjchem.com/topic-1-stoichiometric-relationships.html All videos can be found on YouTube as well: https://www.youtube.com/channel/UC8lJSSlRyIBs8pYhQBnCOIA Great for revision for the upcoming exams.
Last reply by Alror, -
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Just wondering what the first topics you covered in ib1 were
Last reply by IbTrojan, -
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Okay so I have to find some uncertainties for my calculations... First, I have to calculate number of moles of X and that goes like this: n=c*V = A + B = D In order to find the uncertainties for n(X) I add the percentage uncertainties for each A and B. Now the ratio of two reactants is 1:5 therefore I have to multiply the answer D with 5 so: 5 * D = E And now I get confused as to how to calculate the uncertainty when I have this multiplication of 5. Is the uncertainty only the uncertainty of D or? Hope you are not too confused about this...
Last reply by Raptor123a, -
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So i have a question regarding significant figures... if I multiply (5/1) * 0.000352 would that be 0.00176 or 0.00200? I'm calculating number of moles and the ratio is 1:5 that is why I have 5/1
Last reply by Raptor123a, -
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H2O(aq)- water is dissolved in an aqueous solution... INCEPTION? I'm going into Pre- IB next year, and I was just studying for Chemistry HL (we have to express interest in the courses a year in advance). While I was studying, I thought of this equation and found it somewhat contradictory to itself. Again, I'm no where near old enough for the actual IBDP, therefore this question may be a bit ridiculous. Please don't judge.
Last reply by Vioh, -
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Hello, I wanted to get your opinion if I should take chemistry HL in the IB next year (i am in 10th grade). In my previous school we did not have the IB program and we learned chemistry less, but this year we started learning chemistry and i got pretty good grades 6s and 7s (sometimes 5s). But I was wondering if I should be in such a hurry to want to take it in the IB HL next year? Should I wait a bit longer to see how it goes until the rest of the year? Thank you.
Last reply by Sandwich, -
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Just as the title sais.. What are some catalysts that are not in their solid state? I'm looking for an aqueous catalyst. Thanks in advance!
Last reply by Baller97, -
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So... chemistry IA... i was wondering what is the uncertainty of pH meter? I know we may use different ones and so on and so forth but I just want to see if +/- 0.02 seems reasonable?
Last reply by Esteban, -
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I took IGCSE before I began the IB, and when I studied for the sciences I used the syllabus as reference to making notes. But when I look at the IB Chemistry syllabus.... I don't know how to use it? The structure is weird and I don't know what it's asking me to do. I'm more used to the syllabus being straight forward (e.g. Describe the ionic bond as the result of electron transfer and so on) so I'm having trouble getting used to this one. Does anyone have some advice?
Last reply by kespur, -
Hey, So I am currently doing my IA, and I have a question regarding the equivalence point.. From what I've read there is a way to find the equivalence point on Logger Pro using first and second derivative, and this is what I got: 1st der: 5.02 mL 2nd der: 5.33 mL Why is there such a big difference between 1 and 2 der? Also, are there some other ways of calculating eq point?
Last reply by IbTrojan, -
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Hey guys, so I have my mock Chemistry exam tomorrow morning. For the Lewis structure, what are some exceptions to the octet rule?? Also, are there any specific topics/information that I should know or focus on? Thank you!
Last reply by Emmi, -
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For our chemistry class, we were asked to find the empirical formula of hydrated copper sulfate, heating it and finding the moles of anhydrous copper sulfate and water using stoichiometry. My question is that when hydrated copper sulfate (has a blue color) turns into anhydrous copper sulfate (the water evaporates and it is a white/grayish color), while we carried out the experiment it turned slightly green. What could this possibly mean? Could it be that perhaps we "overdid" the experiment or maybe the equipment was "contaminated" and it contained HCl or something? What would be the scientific explanation behind that? I tried looking it up on the internet, but I dont see…
Last reply by elihid98, -
IB Chemistry (HL & SL) Questions
by Guest Aniruddh- 2 replies
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Guys and Gals, I'm seven months into my IBDP (wow, time flies like anything) and my second cyclic tests are starting soon with Chemistry being the first one (in 2 weeks). The latest chapter that was taught to us is bonding, however the concepts are not yet clear to me (especially the whole hybridisation and sigma/pi bond thing) so I thought I would just do some questions. The problem is, that I don't want to do past papers because our tests are made out of them and there is a chance that I might have already solved some questions on my test which would inflate my score - the last thing I need. So if any of you know of a resource/website that has questions on the 2016…
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Anyone know where to get IB chemistry questionbank SECOND EDITION? Just contacted IBO store and they said the second edition is no longer selling. :| Thanks!
Last reply by ultimateone, -
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If anyone has any past years' IB Chemistry SL Papers please inbox them to me at [email protected] or if you have any link to it please share the link. Thank You.
Last reply by Arabgirl88, -
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Hello, So I've initially taken ESS since August 2014 until I moved school. At my current school, they do not offer ESS, so I had the choice between Physics or Chemistry, so I chose Chemistry. Now I really need some notes and some extra worksheets I can compelte in order to catch up. I'd really appreciate if any of you could share a few ideas. Thanks!
Last reply by ibprincess, -
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For a chemistry lab, we need to find the number of moles with this given information: Mass of the Lighter (before) = 13.088 ± 0.001 g Mass of the lighter (after) = 11.323 ± 0.001 g Temperature of the water = 22ºC + 273 = 295 K Volume of the gas = 93.9 ± 0.05 mL = 0.0939 ± 5.0 x 10^-4 L Room air pressure = 1015.8 hPA ÷ 10 = 101.58 kPa ± 0.005 kPa And after finding the moles, we need to find the mass of the gas. The problem that I'm having is that I don't have the molar mass, so how am I supposed to find the mass with just moles?
Last reply by IbTrojan, -
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I finished my Chemistry Paper 2 for my mocks. I encountered this dilemma. This question asked to calculate the enthalpy change, I'm pretty sure there was something wrong with the answer, but I continued to do it as I can get some marks from the steps. Let's say I got 100 The next question uses the answer from last question, it also says (if you didn't obtain an answer for the previous question, use 200 but this is not the correct value). My answer isn't close to 200, but I decided to use the answer that I got from the first question, that is 100, because I obtained an answer for the previous question. Do I get error carried forward marks if all the steps are correc…
Last reply by Baller97, -
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The equation: C3H8(g)+5O2(g)--> 3CO2(g)+4H2O(l) The question asks to predict the number of moles of oxygen gas used in the reaction, but what do you do when the command term says 'predict'? Also it says that there were 8.0 mol of propane present before the reaction and 3.5 mol of methane present after the reaction. I am not sure if that's a typo..
Last reply by ShootingStar16, -
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Hello, I have a chemistry SL Kinetics Design Lab due tomorrow The formula given is You will be investigating a factor that affects the rate of the following reaction: CaCO3(s) + 2H+(aq) ïƒ Ca 2+(aq) + CO2(g) + H2O(l) o Identify a problem you wish to solve and frame your problem as a hypothesis, you o Identify your variables (MV, RV, and relevant CVs) o Design an experiment that will enable you to test the validity of your hypothesis. must be able to explain the hypothesis. Assume you are given any equipment you need (available in any high school laboratory).  Be sure you procedure answers your problem statement AND is designed to control other vari…
Last reply by Vdmrus3.14, -
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Hello! I'm really bad at lab reports so I would appreciate your help I have to do an design lab on the topic "Investigate an aspect of acid base reactions". The problem is, that I don't even know what such an aspect would be... If you could just help me with that and give me some ideas what I can write about I would be so happy! Thanks in advance!
Last reply by Emmi, -
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Hey I'm in my first year of HL Chem and I just cant seem to understand uncertainties. Could someone explain them to me please?? Thank you soooooooooo much!
Last reply by Msj Chem, -
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Hello survivors! Is it okay if I do calculation in Design section? I have different concentrations as my Independent Variable, and the aim of the IA is to find an unknown concentration using a known concentration of another solution. Using Titration in short. The question again; where should I show the calculations of finding the different concentrations of my IVs? Thanks in advance.
Last reply by Emmi, -
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The aim of my investigation is to determine the enthalpy change of this reaction: 2NaHCO3(s) Ã Na2CO3 (s) + CO2 (g) + H2O (l)2NaHCO3(s) Ã Na2CO3 (s) + CO2 (g) + H2O (l) Since this is unable to be done directly, it has to be done using a Hess' Law triangle, indirectly using these two equations: 1. NaHCO3 (s) + HCl (aq) Ã NaCl (aq) + H2O (l) + CO2 (g) 2. Na2CO3 (s) + 2HCl (aq) Ã 2NaCl (aq) + H2O (l) + CO2 (g) Using the formula q=mcat, I should be able to determine the enthalpy changes of these two equations in order to indirectly find out the enthalpy change of the initial equation. However, I have been trying this and have not had much success. For equation…
Last reply by Jwarner, -
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Okay so I'm doing an enthalpy of combustion lab report for Chemistry. It's on the isomers of butanol. I calculated q, which turned out to be 0.330 kJ/mol for Butan-1-ol. The literature value for Delta Hc is -2675 kJ/mol. When I'm trying to calculate the percentage error between these two values, I keep getting 99.99%! Am I doing anything wrong? All help is much appreciated!
Last reply by Baller97, -
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Hey guys, I have a quite stupid question. I can ask it when the school begins next year but I can't wait for the solution. It will be awesome if you could explain the process to me step-by-step. Thanks here is the question A student wished to determine the percentage by mass of calcium carbonate in an eggshell. She reacted 3.953g of the eggshell with 50cm3 of 1.00moldm-3 hydrochloric acid. After all the shell had reacted, the resulting solution was placed in a volumetric flask and the volume made up to 100cm3. 10.0 cm3 of this soluiton reacted exactly with 12.65cm3 of 0.100moldm-3 sodium hydroxide solution, NaOH(aq). Calculate the percentage by mass of calcium carbon…
Last reply by Baller97, -
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Hey guys So I'm in my second year of IB and I'm still struggling with Lab Reports. I really really need to do well. Any tips on how to write a great lab report? Any specific format/method you should follow? Etc. Any help is much appreciated!
Last reply by Intuition, -
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Ok so we did a lab on producing solid copper from copper (II) chloride dihydrate and when I drew up the data table, I got over 100 for percent yield while everyone else got under 100. I'm so scared... I know there's a contaminant and I know what it is, but I wanted to hand it in for feedback and I'm scared I won't do good on it. I'm also panicking because I got weird numbers due to that contaminant.
Last reply by King112, -
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Any tips/advice on how to write up the lab reports (IA's) for Chemistry? Like, anything I should/should not do? I'm in IB year 2 and I'm still struggling.. All help is highly appreciated!
Last reply by Vioh, -
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Hello Everyone, So I have a DCP/ CE lab focused on the Kinetics Chapter. What we have to do was take a sample of the solution we made and place it in a colorimeter which was connected to a probe and take the absorption value at 0sec (inital value) and take it after 120 secs (final value). We had two group which collected data from each other at the end: One kept FeCl3 constant at 25mL, and changed the volume of KI and water. So.. Experimental Group 1 : 25mL FeCl3, 5 mL KI, and 20 mL of H2O Experimental Group 2 : 25mL FeCl3, 10 mL KI, and 15 mL of H2O Experimental Group 3 : 25mL FeCl3, 15 mL KI, and 10 mL of H2O Experimental Group 4 : 25mL FeCl3, 20 m…
Last reply by Ibcanadian123, -
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Hi , I am in need of an online chemistry tutor .....please advice...and which is the best textbook for chem as the one I am using is by Hooder education which I don't find so suitable as it does not have detailed explanation...please advice..
Last reply by Msj Chem, -
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Hey guys, So as you're all aware the HL Chem syllabus changed this year (first examinations 2016), and for that reason new books were published. I've heard many times that the HL Chem Pearson book is the best, and my school has these books (for HL Chem) but only for the old syllabus. For the new syllabus (this year) my school bought the Oxford books (which is both SL and HL Chem; not HL only like the HL Chem Pearson book). This is the book I'm talking about: https://global.oup.com/education/product/9780198392125?region=international I've also heard that there's a HL Chem Pearson book edition 2 (for the new syllabus) now. How does that book compare to the Oxford one (f…
Last reply by NiCKEL, -
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I'm writing a lab report about the "Energy of combustion of alcohols". In the lab we used combusted different alcohols in spirit burners but the alcohols we used are diluted to some percentage (e.g 91% isopropane). I remember my teach telling us to record these percentages but I'm not sure what for Should I simply state that it's a diluted value or am I supposed to calculate something with the percent?
Last reply by mechnight, -
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HEY x.x So I am stuck here (attached photo) I and don't understand the last two questions(3 and 4)? I am supposed to write the equation? If so, where to I go from there? Also, in my background/theory for my lab report, it states that it should be a ratio of 1 to 1.
Last reply by Noticeably Absent, -
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In the 2014 edition of the oxford textbook, the author wrote that the correct way to show a configuration is [Noble Gas] 3dx4sy. The writer even provided justification for it. However, the study guide from the same publisher (oxford) said the correct way is [Noble Gas] 4sy3dx. I know that the latter is more conventional, but has the IB shown preference for one or the other in previous years, or given any updates on it?
Last reply by Msj Chem, -
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Hi! I know that somebody has already asked this question approximately two days ago but I too struggle with writing lab reports for IB Chemistry (SL), even though I'm already an IB senior. I have read the "IB Guide to Writing Lab Reports" and it was quite helpful but I guess I still need some guidance. I was wondering if anybody had some kind of "lab report writing for dummies" advice, preferably specifically about writing lab reports for IB Chemistry. To be honest, I'm quite horrible at science... Also, I happen to lose points in my DCP section due to bad propagation of uncertainty and significant figures so any kind of advice on that would also come in handy. Thanks i…
Last reply by Sceptyczka, -
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Check out my website with a full set of (free) tutorial videos made specifically for the IB chemistry syllabus old and new syllabi (including options B, E and F): www.msjchem.com YouTube channel: https://www.youtube.com/channel/UC8lJSSlRyIBs8pYhQBnCOIA Now updated with new syllabus information.
Last reply by Msj Chem, -
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Hi! Im doing my EE in Chemistry (HL student), with the following RQ: "How is the degree of unsaturation in fatty acids affected by exposure to high temperatures?" (Degree of unsaturation is Iodine Value) I have gathered data from 9 titrations (3 with peanut oil, 3 with olive oil, 3 blank tests), all 6 oil-samples had been exposed to ca. 300+ degrees celsius for 10minutes prior to determining the IV by Hanus' Method. This data will be measured against the secondary-data values of the exact same oils. What tests can I do with this data, and show graphically? Chi-squared test? T-test? Pearson correlation coefficient? Any and all other tips will be appreciated as …
Last reply by Panzer, -
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So today we did a lab on melting points of fatty acids and we have to draw a best fit line for the graph. This counts for marks, but I suck at drawing best fit lines.. Help!
Last reply by King112, -
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Hey all, I have to come up with a design (experiment) for chemistry, related to galvanic cells/voiltaic cells. This is one of our last labs and Id really appreciate if someone could help me:/ considering I have done poorly in all my other labs . Could anyone suggest an Idea for a design; i have no idea what to do it would laos be nice if someone could look over my work once its done perhaps? the specific assignment is: Design an experiment investigating a factor that affects voltaic cells (galvanic cells)... Thanks already
Last reply by Emmi, -
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I've been trying to think of an IA I could do on voltaic cells for my Chem SL class and I'm having a hard time finding many variables I could manipulate. I know that I can change the metals and reactions will/won't occur based on the activity series, but that's about all I've actually learned in class. I've tried googling around, seeing if concentration/temperature/salt bridge/etc. will affect the reactions, but I can't find anything that isn't insanely difficult for me to understand (chemistry isn't my strong suit haha). I've asked my teacher about it and he just says, "I don't know if anything will happen, why not test it and find out?", which, I understand, this is the…
Last reply by kit_2014, -
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Hello, I was wondering if there are syllabus or even instructions somewhere to use TI-83 in the Kinetics Chemistry HL? Thanks a lot!
Last reply by Ossih, -
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Which substances are soluble in hexane C6H14? C8H18 H20 CH4 I have no idea how to do this... Help please Thanks a lot
Last reply by Msj Chem, -
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Hello! I'm looking for an EE topic in chemistry and I've been thinking about the effect of the presence of a magnetic field on the reaction speeds of different reactions. This is very clumsy wording and I don't know if that's even a thing that you can do. What reactions would be useful to experiment with in this case? How to find a less clumsy way to put an idea into words? Is there something else that influences the reaction speed(or balance or whatever really) that is not too overdone? Or maybe I should choose a different topic entirely? I want an original topic but I don't know what I'm doing and where to get good ideas PLEASE HELP Thank you in advance
Last reply by Vioh, -
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how many atoms of hydrogen are in 0.500 mol of ch3oh molecules? I don't know how to approach the question... Could anyone please help me?
Last reply by spacescampi, -
- 1 reply
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For a device i am using for a chem lab... the uncertainty of a temperature probe at 0 C is plus minus 0.2 and the uncertainty at 100 C is plus minus 0.5 C. So if the temperatures in my lab are between 0 C and 100 C, what do I do?
Last reply by Emmi, -
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I don't understand this question. Give the formula of the complex ion formed between a. iron (III) ions and six cyanide ions b. copper (II) ions and four chloride ions c. cobalt (III) ions and three 1,2-ethanediamine bidentate ligands. I don't think I have learned this yet... but it was hw.
Last reply by Msj Chem, -
- 4 replies
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Hi guys, So I started HL Chemistry about 2 months ago, and so far I think it's okay, except for Paper 1. We just finished Atomic Structure (Unit 2) and now are doing Stoichiometry (Unit 1), and I always find Paper 1 harder than 2. The reason being, in Paper 2 you're allowed calculators, but in Paper 1 you're not. Given that, our teacher told us that Paper 1 will have 'easy' numbers thus making mental calculations easy. However, from the tests/quizzes I've had for Paper 1 (especially for Unit 1: Stoichiometry) seem insanely difficult. I mean literally we're asked to convert mass to moles, moles to mass, moles to molecules, molecules to moles, mass to molecules, molecules…
Last reply by Mathemagician, -
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Hello I missed my entire Organic Chemistry unit because I was severely sick. I was wondering if you guys know of any detailed resources that'll help me recover? Thanks!
Last reply by Msj Chem, -
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Hi, I would really appreciate a full explanation of the process of the following question Chlorine gas is produced by the reaction hydrochloric acid, and the oxidizing agent manganese (IV) oxide, MnO2: MnO2+ 4HCl = MnCl2 + Cl2 + 2H2O At 273.15 K and 100 Pa, 58.34 g of HCl reacts with 0.35 mol of MnO2 to produce 7.056 dm^-3 of chlorine gas. Deduce the limiting reagent, and calculate the theoretical yield of chlorine.
Last reply by Turquoise_96,
