Chemistry
For Chemistry Discussions
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Hi! I am one mark away from a 7 in my hl chemistry and my teacher tells me I should remark, but I'm not sure I should. She gave me my components; I got a 63 in paper 2 and the 7 starts from a 66, and I got a 36 on paper 3 and the 7 starts from 38. I got a 7 on the practical work and I'm one mark away from a 7 in paper one, but these are not regraded. Overall, I got a 78 and the 7 starts from a 79. Do you think I should remark? Is it likely that I get raised to a 7? Thank you!!
Last reply by IBdesperate, -
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Hi everyone, I have my chemistry coming up really soon, and have a burning question to ask! Thank you so much for your help in advance. My aim is to measure the reaction rate of a reaction, to see the relationship between reaction rate and reactant concentration. I thought about two methods, and I would like to ask if they will work, and which one is better. 1) Do the reaction 2HCl(aq)+Mg(s)→MgCl₂(s)+H₂(g) and measure the mass of the reactants at the beginning, and after a set period of time. (then calculate the reaction rate). I will change the concentration of the HCl every time. 2) Do the reaction between sodium thiosulfate and hydrochloric ac…
Last reply by kw0573, -
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Hello, I am doing a chemistry IA on reaction rate using titration, and have one question I would like to ask. First, the reaction I might use is CH3CH2Br+OH−→CH3CH2OH+Br- I'm going to stop the reaction by adding Hydrochloric acid, then titrate with Sodium hydroxide solution to see how much HCl was left over. From that, I can calculate the rate of reaction. BUT THE PROBLEM IS: I don't have access to CH3CH2Br What other substance (preferably a common one) can I use for this experiment? Thank you so much!
Last reply by Mao, -
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Hey there! I am planning to do a chem ia about the decomposition of hydrogen peroxide and going to give an answer to the best catalyst in this reaction. My point for the personal engagement is that I burned myself with hydrogen peroxide, so I want to know the fastest way to make the concentration of the hydrogen peroxide smaller. My teacher says that people can argue that adding water is another way, so she thinks i dont need to know this. Also, she says that oxygen is more dangerous so why decompose it? So......what should I do? do you think I need to think of something else? PLEASE HELP ASAP!!!!!!!!!!!!!!
Last reply by kw0573, -
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I'm now finishing year 11 and I got a 3 on my paper 2 final exam. Generally I am a 6 student but due to procrastination this semester I began studying a week before the exams. I want to study nutrition which is why I took chemistry hl but now I have the issue that i need a 6 to get accepted into uni. I don't wanna change schools and not do the ib nor do I want to repeat the grade. Please help, how do I boost my grade?
Last reply by DrW, -
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Hi everyone, Right now I'm starting to think about my Chemistry IA, and it would be great to have at least some ideas before summer break. I want to study Pharmacy or Bioengineering at university, so I thought of doing something along those lines for my IA. Also, my friend is writing her EE in Chemistry, and she is comparing the effectiveness of different stomach antacids. I really like this idea, but, obviously, I can't steal it, so I have to come up with my own idea.. Could you please help me with this? Thank you in advance!
Last reply by DrW, -
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I had my chemistry mock today...and...well...rip
Last reply by sophiadsouza, -
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Hey guys, I have actually finished my Chem IA (draft is due in a month) but I think I screwed up. My question is 'What is the mass percentage of calcium carbonate in Hawkesbury Limestone' (a type of limestone where I live). I realised I can't do any graphs or anything and can only calculate mass percentage for 5 samples then average them. Is this really bad and what can I do if so? I'm not aiming to get a 7 in Chem but at least a 5/6 (SL). Cheers !!!
Last reply by Lord of the Pickles, -
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Hey all, I’m writing my paper 1 and 2 tomorrow, and paper 3 the next day. However I feel rather unconfident with what prep I’ve done for paper 3! Do you guys have any tips and tricks or things I should keep in mind on both part A and B? I’m doing Option D, Medicinal Chemistry.
Last reply by NishantEC, -
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Which element forms more than one stable positive ion? A. Ca B. Cr C. Zn D. Ba The answer is B, but how? Thanks!
Last reply by Cherries, -
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Which compound can both be esterified and turn acidified potassium dichromate (VI) solution green? A. (CH3)3COH B. CH3CH2CO2H C. (CH3)2CHOH D. CH3CH2COCH3 The answer is C, but how? Thanks!
Last reply by kw0573, -
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Which molecule is non-polar? A. OF2 B. NH3 C. BF3 (answer) D. SO2 How do we know this without using the electronegativity values? Thanks!
Last reply by kw0573, -
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The graph below illustrates how the vapour pressures of ethoxyethane, CH3CH2OCH2CH3, benzene, C6H6, and water, H2O, change with temperature. Using data from the graph, explain the difference in vapour pressure of ethoxyethane, benzene and water at 30 °C. ANSWER: water has hydrogen bonding; benzene has van der Waals’/London/dispersion forces; ethoxyethane has dipole–dipole forces (and van der Waals’/London/ dispersion) but they are weaker than benzene I understand the forces of each of these substances BUT how does it relate to their positions on the graph? Thanks!
Last reply by kw0573, -
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Does the number of delocalized electrons equal the number of valence electrons for an atom? Thank you!
Last reply by Cherries, -
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Bromine was added to hexane, hex-1-ene and benzene. Identify the compound(s) which will react with bromine in a well-lit laboratory. Answer (according to markscheme): hexane AND hex-1-ene; Accept "benzene AND hexane AND hex-1-ene" I thought that the answer would be hex-1-ene and benzene as hexane is saturated (the bromine water test). Why is it not?
Last reply by kw0573, -
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Hello, I'm currently in year 1 of IB and I'm contemplating whether I should drop Chemistry HL to Chemistry SL. Also, I would like to know whether or not I'm required to take it at HL if I want to study undergrad bio in Canada or the US. Reasons why I want to drop: - Bad grades 4s and 5s sometimes 3s - I'm only doing it to strengthen my application - The Chem SL teacher is better - I love English literature My current subjects are: Chem HL, Bio HL, Business HL, English Lit SL, Math SL, Arabic Ab inito If I drop to Chem SL: English A Lit HL, Bio HL, Business HL, Chemistry SL, Math SL, Arabic Ab inito I've been thinking about this for…
Last reply by cluelesskidd, -
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On the IB Chemistry Syllabus (or any experimental science for that matter), there is a section that is titled "Utilization". It just refers to other practical links to the concepts in each chapter. Are we supposed to know these links for the actual exam? Thanks!
Last reply by kw0573, -
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What is the approximate pH of a 0.01 mol dm–3 ammonia solution? A. 2 B. More than 2 but less than 7 C. More than 7 but less than 12 D. 12 The correct answer is C. I know that A and B cannot be the answers but how would you do this question without actually doing the math as the answer could be C or D?
Last reply by kw0573, -
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The diagrams below represent equilibrium mixtures for the reaction Y + X2 ->/<- XY + X at 350 K and 550 K respectively. Deduce and explain whether the reaction is exothermic or endothermic. (350 K VS. 550 K) Thank you in advance!
Last reply by kw0573, -
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Attached is the question. The answer is C, but I do not know why. Thank you! http://www.easynotecards.com/print_list/21945?fs=2&dis=1&pi=on
Last reply by Cherries, -
- 0 replies
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Hi, for my IA I wanted to analyze the composition of e - cigarettes liquids and vapour produced by the device. Is it even possible to choose such a topic, I mean does IBO accept experiments with drugs (or how to describe an e-cig) etc?
Last reply by Filoo, -
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The reaction below represents the Haber process for the industrial production of ammonia. N2(g) + 3H2(g) 2NH3(g) ∆HO = –92 kJ The optimum conditions of temperature and pressure are chosen as a compromise between those that favour a high yield of ammonia and those that favour a fast rate of production. Economic considerations are also important. Which statement is correct? A. A higher temperature would ensure higher yield and a faster rate. B. A lower pressure would ensure a higher yield at a lower cost. C. A lower temperature would ensure a higher yield and a faster rate. D. A higher pressure would ensure a higher yield at a higher…
Last reply by kw0573, -
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1.0 g of sodium hydroxide, NaOH, was added to 99.0 g of water. The temperature of the solution increased from 18.0 ºC to 20.5 ºC. The specific heat capacity of the solution is 4.18 J g–1 K–1. Which expression gives the heat evolved in kJ mol–1? A. (2.5 × 100.0 × 4.18 × 1000)/40.0 B. (2.5 × 100.0 × 4.18)/40.0 x 1000 C. (2.5 × 100.0 × 4.18 × 40.0 )/1000 D. (2.5 × 1.0 × 4.18 x 40.0)/1000 The answer is C but I'm unsure where the 40.0 came from...
Last reply by Cherries, -
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Which equation represents the bond enthalpy for the H–Br bond in hydrogen bromide? A. HBr(g) → H(g) + Br(g) B. HBr(g) → H(g) + Br(l) C. HBr(g) → H(g) + 1/2Br2(l) D. HBr(g) → H(g) + 1/2Br2(g) The answer is A. I understand that all substances should be involved should be gaseous, but why cannot the answer be D? Thank you!
Last reply by Cherries, -
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Hi, I am currently in Grade 11, still unsure of my EE topic. I've tried to work on different topics such as making biofuel out of coffee beans, analyzing aluminum content in deodorants and more, but those ideas have not been very successful. I have been thinking about working on making polymers out of organic materials such as potato starch and maybe corn starch etc. and measuring the strength or a measurable property of the final plastic result. I could also possibly link it to bond strengths or how propan-triol acts as a plasticiser that change the properties of polymers, as they get in between the polymer chains and prevents them from lining up in rows to form a …
Last reply by Zhe Yu, -
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Hi guys, So I'll be giving my exams this May and, I've taken Chemistry HL .Now, the problem i have is that, I haven't been doing well in chemistry.Constanlt getting a 4 or a 5 has really made me doubtful of getting a 7.I have studied all the chapters thoroughly and I've noticed that the problem usually lies in the exam.I tend to get nervous and then blankout.In addition, I alos tend to write anwers that are not according to the marking scheme. If anybody has any tips on how I could bring my marks to a 7 or , maybe even a 6 I would be really grateful.
Last reply by Tragic Survival Chances, -
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Has anyone here used Oxford's study guide (Geoffrey Neuss) before and done well on option B? Is there anything that you found was missing from the book? Thankyou!
Last reply by hibhouba, -
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Hi, For my Chemistry IA, I want to compare the activation energy of the decomposition of hydrogen peroxide catalayzed by potassium iodide (KI) versus the activation energy of the decomposition of hydrogen peroxide catalyzed by a solution of catalase enzyme, to determine which one is the more efficient catalyst (i.e. the one that yields a lower activation energy for the reaction). For both catalyzed reactions, I'm going to measure the volume of oxygen gas evolved per second using a gas syringe, at 5 different temperatures (30°C, 35°C, 40°C, 45°C and 50°C). Then, I'm going to create an Arrhenius plot for each catalyzed reaction, and determine the activation energy from…
Last reply by Ali1415, -
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I keep seeing different values. Does IB (2018) use STP or SATP and what are the values? e.g. is 1 atm 101.325 or 101 or 100 kPa? Thanks!
Last reply by Msj Chem, -
How would an IA using the Winkler method to study the dissolved oxygen in a river at different points be? What improvements should I make? Thanks
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hello!!! does anyone know if the bibliography page of the chemistry ia counts for the page number (which is maximum 12)?
Last reply by Rosalina, -
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For my chemistry experiment, I decided to find the effect of temperature on the equilibrium constant of the reaction between Fe(NO3)2-and AgNO2- using KSCN to Titrate the equilibrium mixture. My concern is will this method give me sufficient results for the aim of my investigation? Also, I haven't found any applications for this reaction. Please let me know if there are any. thanks
Last reply by NicknameTara, -
Chemistry SL problems
by Guest- 3 replies
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Okay, so I have been studying really hard for Chemistry SL, I work on it for 2-3 hours a day and although I do understand the fundamentals of chemistry, I just have a really hard time putting my knowledge on papers and elaborating my chemistry skills. So I got a predicted of 3 in Chemistry SL but overall in IB I am predicted high 30's. All my courses have a 5 or 6 but just chemistry is predicted a 3. This is the only course bringing me down and I have come to realize it is not for me, naturally. Does this mean that I could lose my IB diploma if I get a 3 in Chemistry SL IB in the final exam?
Last reply by kw0573, -
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Hi, I just wanted to know whether there was a specific order to revise the topics for both SL and HL? There's so much inter-topic knowledge so I wanted to know whether there was a beneficial way to revise and understand the topics. Sorry if this is a bit confusing!
Last reply by Lixter, -
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Hey guys, so in our recent mock exams, I got the grand total of 3 for my chemistry mock, which includes paper 1 and paper 2. I did significantly worse is paper 2, and what I want to know is if there is any hope of getting a 6 in the final exams. I have major gaps in my knowledge especially when it comes to explaining concepts and applying knowledge. I have to confess that I didn't study as much as I should have, but at that point I had just given up because there was too much to revise in too little time. What I want to know is if you guys have any tips or anything at all that could help me. Richard thornley and MSJ chem's videos do help with understanding the concepts bu…
Last reply by yara560, -
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Hello, I'm searching for two students, which are full of motivation that would like to form a team and participate in a competition together. The theme I really want to work on is air pollution analysis. I think this is a great opportunity to try yourself in a different field, gain new cooperation skills and of course have something to write in your personal statement. (Ha ha ha we are all worrying about that last point, aren't we?) I hope someone will return my call! Have a nice day! Note: All three students have to be from different countries and from the European Union between 15 and 19 years old. You can find more information about this competition her…
Last reply by The Nun, -
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Can you use confidence intervals on bar charts? I did my IB Chemistry IA experiment on the effects of varying antacids on the pH of HCl so I have a bar chart with the types of antacids on the x axis and then the mean change in pH on the y axis. I wanted use confidence intervals to show how much of my data is due to random error but I started hearing that CI is only for t-charts. Does it make sense to use CI or should I just use standard deviation or standard error? I’m in both IB Chem and Bio and my two teachers are telling me different things about stats and uncertainty so I’m getting quite confused on when and why to use different types of data analysis.
Last reply by Cschreiner7701, -
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Hi guys, I did an experimental ee based on a research done by previous scientists, and I explained important parts of the research that are related to my research question in the introduction. So, will the examiners still check again that research? Or they'll just depend on my explanation in the introduction? Curious about this, thanks!!
Last reply by 12345e, -
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Hey guys, I'm trying to convert the amount of Mg2+ ions in MgSO4 (molar mass:120) to ppm. This is a little confusing to get my head around. I wish to convert 0.5 moles/litre Mg2+ ions (12 grams per litre) to ppm. This is quite urgent. Thanks in advance for your help!
Last reply by Befuddled, -
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Hi everyone, For my ia I decided to do a simple vitamin c titration from different fruit juices and compare this to their labels. My teacher said the procedure has pretty much been done countless times before and my report would have to be flawless to get a good grade. She also was iffy on the comparing my values to the label values since those were calculated by actual professionals. Any suggestions for how I could put a spin on a vitamin c titration? Or should I just trash the idea? Thanks any advice is appreciated.
Last reply by SaraPir, -
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Hello guys, I have an urgent question about carboxylic acids. Which one of them has the strongest positive inductive effect? I know propanoic acid has a greater pKa than butanoic and pentanoic acids, but does that mean that it has the greatest positive inductive effect(if you consider methanoic, ethanoic, propanoic, butanoic and pentanoic acids)? Please help me i'm so confused.
Last reply by IBlearner73, -
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So I'm at the conclusion of my experiment and I'm struggling to find an alternative method to find iron Fe2+ in food contents. I already did a titration and spectrophotmetry which is the reason I am finding it difficult to find yet another method. Any ideas anybody? I'd be very thankful
Last reply by Legend3107, -
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Hey guys, I have 3 different enthalpy values with 3 different absolute uncertainties. So if I calculate the average enthalpy, how do I get my uncertainty?
Last reply by IBlearner73, -
Hey guys, I recently started planning out my chemistry SL IA. I was thinking of using different materials and analyzing how they affect the calorimeter. I was thinking of linking this to the thermodynamics module. I was thinking for example of using styrofoam cups, metal, plastic. Do you think this would be a viable analysis, as I'm wondering if there really is something to analyze here... thanks a lot, Cyril
Last reply by Cyril O'Brien, -
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Hey guys, I'm soo confused about the absolute uncertainties that I really am hopeless. How do you do your uncertainties for calorimetry? I have used a pipette (twice) for volume measurement, and then I used a temperature probe with additional uncertainty. But given that you multiply temperature with the mass(deriving from the volume of solutions if you are using acids and bases and you assume that they are mostly water), how do you calculate the % uncertainty? Do you add the percentages, do you multiply them or what? And also what is the absolute uncertainty? I thought that you get absolute uncertainty when you multiply the total percentage uncertainty(when you add t…
Last reply by IBlearner73, -
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Hey guys, So I have done an experiment on calorimetry, but I don't know how exactly you can show personal interest in the introduction. Do you have any guidelines for showing personal engagement in introduction? Thanks.
Last reply by IBlearner73, -
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Hello guys, I don't know how to shorten my IA, I feel like it is concise enough, but I have also so many graphs that have to be included, and will it be okay if I reduce their size? How did you guys make it fit into your page limit? Please share any advice, thanks.
Last reply by IBlearner73, -
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Hey Guys, I ma working on my chem HL IA, and my topic is to determine the amount of folic acid in bee pollens coming from different regions of the world like Italy, Australia, etc by titrating it with NaOH. However, there are little information about bee pollen and specifically folic acid in bee pollen out there in the internet. Therefore I am finding it very hard to know how to extract the folic acid from the bee pollen, because from my knowledge there are other acids that contribute to the pH of the pollen. However, I am specifically focusing on folic acid and I really don't know how to extract it. Could you guys please give me some help or guidance ? Worst c…
Last reply by KikiS, -
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My IA chemistry proposal duedate is about time. I really need your opinion on my ia chemistry hl topics. I had two ia topics on my mind; 1. The effectiveness of gastric pain medicines to neutralise hydrochloric acid (magnesium tablets, powdered or liquid) 2. Which type of sugar produces more carbon dioxide in yeast fermentation; natural or artificial? (Is yeast fermentation is a good idea? Or should i go for calorimeter or spectrometer?) Which one do you guys think it's more decent for my chemistry hl topics? I also welcome any recommendations, or comments. Thank you xoxo
Last reply by inriya, -
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Hi! For my chemistry IA, I'm doing it on whether temperature affects buffer capacity, and the buffer solution I'm experimenting with the McIlvaine Buffer. And I know, I'm so stupid for using this buffer cause there's barely any information on it. I was wondering if anybody would know what the equilibrium chemical equation for it would be? I'm a little confused as to how it would work when there's citric acid (C6H8O7) and disodium hydrogen phosphate (Na2HPO4) and then add sodium hydroxide (NaOH) to it as the titrant. I understand the basic buffer equation, with a weak acid and it's conjugate base in equilibrium and hydrogen ions floating around that then r…
Last reply by Vsu,