Chemistry
For Chemistry Discussions
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Help T^T I'm suffering so much I'm doing a DCP and CE report on the UV-Vis spectroscopic determination of extinction coefficient of potassium dichromate and the concentration of an unknown sample. I used 500um standard stock solution of potassium dichromate and diluted to make 50,100,150.....to 300 through serial dilution (so that I can draw the calibration curve). I used a pipette with +/-0.05cm3 and a volumetric flask with +/-0.03cm3 for the dilution, and I'm having trouble with my error analysis. Because I did serial dilution, I have to add +/- 0.08cm3 to every further dilution right? So I'm cool with this I think, I converted the uncertainties into percentage uncertai…
Last reply by Keel, -
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I have design, in it I check the influence of initial temperature on rate of reaction by measuring change in pressure from reaction of metal with non organic acid. It was marked 6/6 (although when it will be sent to moderators it will be marked maximum 5/6 as I know it will be marked by them). Can they take even more point if they'll think the idea is too simple and the result is obvious? Oh, right, I'm on Chemistry HL ; d
Last reply by dessskris, -
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What are the different types of Calcium Carbonate that are used for buildings, old or modern? I already know of marble and limestone, the only factor that seperates them is pressure. I've done some research, the only other material I can find is travertine and that was used for castles in the olden days. Can you help me with regards to other materials, it doesn't have to be a material that a building is made completely out of per se but perhaps a part that the building is made up of? This is for my Chemistry lab, the idea is to get as many CaCO3 forms as possible. Thanks!
Last reply by Markee, -
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How would I do a lab report for a virtual lab?
Last reply by Keel, -
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How would I go about designing an experiment concerning this? Thanks. Can you give me any ideas? Thanks.
Last reply by Markee, -
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Hi, I have a question related to aqueous solutions. If I dilute 1M of NaCl in a given measure of water; and the water dissociates it. Will I have also 1M of ions Na+ and Cl- ?
Last reply by dessskris, -
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Hello!! So I am working on my IA lab reports x_x, and I had a problem relating to the Nernst Equation. E = E° - (RT/nF) ln Q I was asked to investigate factours that affect a certain variable in a galvanic cell I chose the concentration affecting the voltage of a whole galvanic cell; and my plan was to prepare solutions of AgNO3 and CuSO4 in 1M, 0.75M and 0.5 M; and measure the voltage of all the 9 diferent probabilities of the galvanic cell. The problem is that in my lab, the room temperature was not 25°C, so I coulnd't establish a temperature of 298.3 K in my equation. (the room remperature and the solutions were at 22°C). But when I tried to apply the data in the for…
Last reply by Drake Glau, -
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For anyone who's already written the SL Chemistry exam paper, or even a mock exam...what did you think? Is it difficult or alright?
Last reply by Center Field, -
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Hye! I need to know of a way to control the amount of pressure exerted on the pipette, because it's one of my control variables for my design lab due tomorrow! I would also like to know if there is a website that features the ingredients/chemical compounds in household items, like Drano, Honey, Ketchup, and Olive Oil? Thanks in advance!
Last reply by BronxNerd, -
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I have one ml of an unidentified ester and need to come up with a lab. I want to do so mething more than identify the ester. any ideas?
Last reply by Clt, -
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Hello! Well we got the assignment of making a design lab on the theme provided by our teacher "Investigate a factor that affects the rate of a chemical reaction, but it cannot be concentration, surface area or temperature" ....I'm stuck, no ideas what so ever, adding to that I am not a superb chemist so my options are limited. Could really need some inspiration and ideas to get going on this one. Oh and this is also my first design lab EVER!!! Thus I don't really know how to tackle the problem so to say. Help is most appreciated, in all forms!
Last reply by Clt, -
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Are you allowed to have the same procedure for 2 different labs? For example, one lab i did was indirectly test the reactivity of different antacid tablets with hcl by using a balloon (expands with gas produced). Now, i just completed another lab testing the reactivity of different metals with hcl by using a balloon as well. Is this okay to have or?
Last reply by Colin, -
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right, in this experiment I am told that an oxidant X is KIO3 (aq). in the presence of acid, oxidant X oxidises iodide ions to iodine. 1 mole of X produces 3 moles of I2. What I did next was titrating the iodine liberated with thiosulfate ions to reduce the iodine back to iodide. I am stuck with CE and I thought I would just suggest another type of experiment using starch solution. Unfortunately I can't think of one! Does anybody know how a redox experiment involving KIO3, I2 and starch in order to find the Mr of KIO3? Thank you!
Last reply by Drake Glau, -
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so basically i've chosen to do chem HL, well i didn't really have much of a choice, I had to pick from Arabic, math, physics and chem, so decided to go with chem heres the thing though, i'm not exactly a brainiac at chem, and right now im struggling to digest acids and bases (which I've been told is quite an easy topic ) anyway to the point, i was just wondering exactly how hard is chem HL, i LOVE math and able to do well in it, so i'm good at calculations and all and substituting numbers into formulas and all, but when it comes to writing up equations and determining the product i'm not hopeless. but not too great. so in short, is it possible to achieve a good mark with…
Last reply by Drake Glau, -
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Can someone explain how and why convergence occurs? i'm a little confused about how it works..any help would be greatly appreciated !
Last reply by Daedalus, -
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im doing a chem design lab with the reaction between hcl and antacid tablets. I put them both in a flask with a balloon on top and let the balloon fill up and then measure the cirumference of the balloon with string.. do i need a hypothesis since my independent variable is the brand of antacid tablets and my dependent is the size of a balloon that is being filled by the co2 produced? or should i just have a general hypothesis like: if the brand changes, the size of balloon will change as well. Or should i just say as the inactive ingredients of the antacid tablets change, then the size of the balloon will change? any help please. lol
Last reply by Drake Glau, -
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Hey, I need some help regarding dative bonds. I"m having trouble writing the lewis structures for the more complicated ions like CO3^2-. I would really appreciate some help ;p
Last reply by Daedalus, -
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Greetings! I have recently been going through a couple of past papers and these (in title) keep bugging me! Apparently, you can't have any decent Organic Chemistry in Paper 2 that does not mention the m/z peak values of a compound or the ratio of H NMR scans of a compound. Also, regarding the acids. I know that Sulfuric is very hydrophilic and that it will go to the extent of ripping of -OH groups from other compounds. Apparently this is the same deal with Phosporic acid. Now I did scan the fat HL Chem book (the green heinemann which takes 20 pages to explain one simple concept) and I checked the technology and organic options, and what do you know: I found both m/z, H N…
Last reply by Mate, -
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Hello! So I'm currently taking both chemistry and physics in SL, and this year we have been informed about all the lab reports and stuff we have to do (stupid school); and I have already had a mental crash X_X. We were assigned 10 hours of laboratory work, and I have already begun most of them; but I'm having troubles with some things. -Which is the format of the lab reports? x_x I made the classical ones you do in midschool, but I am not sure and the teachers are as lost as I am. My second question is about the "practical" works. WHAT THE HELL ARE THEY (those about the personal skills and that stuff)? The teacher assigned us one about the Factors in the combustion reacti…
Last reply by ILM, -
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Hey guys! I'm doing my chem. design lab on electrochemical cells and need to do some dilutions and have never had to use dilutions before. But anyway , is it better to do a serial dilution than to dilute from the original solution for all the different concentrations?
Last reply by papedudae, -
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I have a grade 4 in my chemistry internal assesment but my aim is to get a 6 in the final exam. I am just wonderin if that is possible. What should i do to be able to get a 6?
Last reply by Stereoisomer, -
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Does anyone know a good website that has questions relating to the acid-base unit? I want to have some extra practice before my test. Please don't give me the link to the syllabus.
Last reply by Stereoisomer, -
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I am interested in going into medicine and know that chem hl would be helpful but I don't know what to expect. I have heard that it is really hard, but it would look better when I'm applying for university. Could you please tell me what to expect and tips for doing well in the course. I'm kind of nervous as I'm going into the IB program next year. Thanks
Last reply by rmd, -
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i dont understand functional groups...i know this sounds odd, but i just cant seem to visualize them....apart from alcohol and carboxylic acid...can anyone help me? how did you get to grips with organic chem?
Last reply by kiwi.at.heart, -
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Im in 2nd yr IB and just can't get my head around quantitative chem!!!!!! I practice questions but i can't seem to get them right!!! HELLLLLLLLP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Last reply by Drake Glau, -
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I did an Energetics lab and I need to plot the temperature against time graphs. In both experiments we reacted a solid and an aqueous solution. We monitored the solution's temperature for 120 s and then add the solid. We needed to monitor the temperature every 30 s until it has reached its maximum/minimum. The problem is that our teacher keeps telling us that our graphs are wrong. The graph should be something like the picture below: It is first constant, then significantly increasing (as they react) and gradually decreasing to reach room temperature. Then create a linear trendline when the graph is decreasing to get the ΔH. The problem is that we monitored the temperatu…
Last reply by dessskris, -
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Any good link site for Ib chemistry revision notes?
Last reply by ILM, -
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help! how much hydrochloric acid (in excess) is needed to fully react 1g, 2g, 3g, 4g, and 5g of aluminium (in separate experiments) thanks guys
Last reply by Alys, -
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Can somebody tell me, is the mass just the mass of the fuel before you start burning it, or do you have to take into consideration the starting and ending masses? Or do I have this completely wrong? I would greatly appreciate any help you can give me. I'm stuck, and I have an IA due in the morning... EDIT: Erp. I'm thinking this paper I have says I should be measuring the mass of the water I'm heating, not the fuel. This is terrible, I feel so stupid.
Last reply by Drake Glau, -
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I'm taking IB HL Chemistry this year. What's surprised me is that I got a borderline 4 on my first exam. Generally, I get the some of the best grades in my class and I got a 7 in MYP Chemistry last year. So it's very difficult for me to understand how I'm barely passing this course. I am very weak in math, and also lack general basic knowledge in chemistry (my previous school's chemistry preparation in MYP was horrible), so I'm guessing that's what's bringing me down and throwing me completely off the questions. Can anyone advise me as to how I could quickly and efficiently catch up and build a good base in chemistry (and math if necessary) that will help me at least get …
Last reply by curlayy39, -
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I need ideas for a design IA on oxidation and reduction topic I also wanted to know a format suggested for a design IA Thanks in advance
Last reply by Drake Glau, -
I am worry about Chemistry IA because our teacher is giving some of us a bad grades due to poor relationship with him but I still want to get 6 or 5 in chemistry. What can I do?
Last reply by master135, -
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Can anyone please help me with how to start my chemistry IA in "Factor affecting the rate of a chemical reaction" in thiosulfate?
Last reply by Drake Glau, -
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Hey, So I have a lab report due tomorrow, and it involves finding Avogadro's Number. The data i have is the height, diameter, mass, and volume of an iron cylinder. I also have the radius of one iron atom. I'm supposed to use this data to solve for avogadro's number. any ideas? thanks anyone? i really need help...
Last reply by Bayloun, -
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I have to write a chemistry lab report on the rate of reaction between magnesium ribbons of different length and water . Does the following make a valid question "Identifying the most accurate methods for determining the rate of reaction between water and varying lenghths of mg ribbons" If not , which I have a god feeling it isn't , is valid , then how do I formulate a good research question in chemistry IA ?
Last reply by dessskris, -
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In order to find the enthalpy (the energy needed to evaporate a certain substance) I need to know the exact volume/mass. What is the volume of a normal drop from a droplet? Does the volume depend on the substance too? I should have found that out while I was doing the lab, but now I need your help to survive [iBsurvival ] // Adam
Last reply by IB-Adam, -
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I got a 70% on a chemistry HL test. Is this a 5 or a 6?
Last reply by Lolcatfevah, -
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My teacher says to think about what I want to learn in Chemistry, but I don't even know!!!!
Last reply by Mahuta ♥, -
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I'm not great at stoichiometry and I really want to practice it more but most of the practice worksheets I find online are too easy and no where near as difficult as the kind of questions that show up on the occasional practice papers that I get. I was wondering whether anybody knew where to obtain some worksheets. Thank you!
Last reply by ppincus, -
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Hey I'm doing Chemistry HL, and one of my options is Modern analitical chemistry I have a question... I don't understand what is gas liquid chromatography and my teacher is really bad teaching...an i'm learning with friends and books...but we really don't understand this THanks
Last reply by Mahuta ♥, -
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I decided to do a Science fair lab on the decomposition of several carbonates. Where can I find sources? I've tried using the databases that my school provides, but I'm not finding anything really pertinent to what I want to do.
Last reply by Drake Glau, -
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Hey guys, I was just wondering what everyone else got on the Chem SL exam, because I got a 4 and I don't really know what to make of that... I thought it was pretty hard (especially paper 2), so what did you all think? Thanks, Ibcrazy
Last reply by ms.s.peverell, -
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Hey Guys, We're doing a project on Avogadro's Law (one of the gas laws), and we need to do a creative, informative lesson (not a presentation). We can't do anything like a song, role play, etc. We have a powerpoint with info, but we really need some additional ideas to make the lesson more interesting. Thanks!
Last reply by dessskris, -
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Hi everyone. Is, is chem hl much harder than chem sl? Do I have more chances to get good marks doing SL? Thanks
Last reply by just_a_student, -
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So, we came back from fall break to a take home unit test on Reduction/Oxidation reactions, and I'm confused on a few questions... How can I tell from a list of several elements/ions which is the strongest oxidizing agent, and which is most likely to be reduced? I know it has something to do with energy potentials, and I have a list of standard potentials in my chem data booklet, but I can't seem to put them together to come up with an answer. Can anyone give me a legup? Cheers, thanks.
Last reply by Mahuta ♥, -
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6. The molar masses of C2H6, CH3OH and CH3F are very similar. How do their boiling points compare? A. C2H6 < CH3OH < CH3F B. CH3F < CH3OH < C2H6 C. CH3OH < CH3F < C2H6 D. C2H6 < CH3F < CH3OH The answer is D, anyone know why? I would have said A, as the difference in electronegativities between H and F are greater than the difference in electronegativities between H and O resulting in a 'more' polar molecule, hence stronger Hydrogen bonds Thanks
Last reply by Mahuta ♥, -
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I'm taking Chemistry HL, but my teacher doesn't give any homework. From time to time a student in the class will beg him for some, but then he'll only give us a few questions, and a lot of the time they end up not being very relevant to what we're learning. The textbook our school provides us with is something waaay beyond our level, so almost all of the questions in it feel like they're written in some foreign language. A lot of the times I think I might understand a concept, but I don't really have a way of testing that since I don't have any practice to test it against, and the Course Companion has a really limited number of practice questions. Does anyone know a reall…
Last reply by CristinaV, -
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My mock exams are 1 month away and I am will start studying frmo tommarow. Any hints, tips, suggestions on how i can do so?
Last reply by Mahuta ♥, -
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A friend of mine and I are doing a science fair project together, and he wants to do something on chemistry. Does anyone have any suggestions?
Last reply by Antiares, -
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Read the title ^^ I just can't work it out, should Cl have a higher melting point due to the greater electrons meaning greater van der Waals forces?
Last reply by timtamboy63,
