Chemistry
For Chemistry Discussions
1,617 topics in this forum
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- 5 replies
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I have okay IAs, my manipulative skill will be lower since I had to redo labs multiple times because of forgetting stupid, minor things. My group 4 was alright, maybe better than most. When we take paper 2 mock exams, I only miss 1 or 2 points. Do I still have a good shot at a 7?
Last reply by Peanut Butter Jelly, -
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Does anyone know what would be a good method of titration? I'm leaning on the side of titration with HCl and NaOH since that's what our instructor is insisting we use. Currently, if I can't get a better idea, I'll be sticking to testing antacids by placing the prescribed dosage in a known molarity of HCl.
Last reply by l0stboy, -
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I've done a lab using energetics instead of a standard titration to find the concentrations of HCl, H2SO4, HNO3, and CH3COOH, H3PO4. In my conclusion/evaluation I was going to mention some source of error coming from the different specific heat capacities of the NaOH I neutralized them with, along with the acids' specific heat capacities, and also the heat capacity of the water which is produced as a result of neutralization. Problem is I cannot seem to find on the internet the specific heat capacities of any of them in concentrated aqueous solution form! What I am thinking is that since they have solute dissolved in them they must have a higher heat capacity than water. …
Last reply by Drake Glau, -
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I have read the guild-lines for how to write a conclusion but I am still don't know what kind of information I should put in it. Can anyone help me?
Last reply by iHubble, -
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Guys, i'm currently in my first year of IB. I have a chemistry IA for titration due tomorrow. I know this is a very simple question but please help! For example I have an equation : H2SO4 + 2NaOH -> 2H2O + Na2SO4 mole of NaOH = 0.05 mols with uncertainty ± 0.01 mols To find the mole of H2SO4 I need to divide 0.05 mols by 2, since the ratio of H2SO4 : NaOH is 1:2. Now what is the uncertainty of the H2SO4??? do i divide it by 2 or is it the same??
Last reply by engourdis, -
Basically, our amazing Chemistry teacher is letting us do one last experiment of our choice on any topic before the May exams this year. I am openly looking for ideas/brainstorms. What experiment do you like? Which experiment did you score highest in? Which ones are easy for DCP and CE in your opinion? What would you pick for maximum marks?
Last reply by Emmi, -
Chemistry SL with a crappy teacher or a hard course of Chemistry HL with a good teacher?
by likeawind24- 13 replies
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Just to give an info about myself: other HLs I take are: Biology, Mathematics, and Economics. Currently I take Chemistry SL but the teacher is really crappy. I don't get what he's teaching about, for his explanations aren't very great. He's new to the school, and he's never taught IB before. On the other hand, the Chemistry HL teacher has taught for at least 10 years. (of IB and in the school). Should I change Chemistry SL to HL just because the SL teacher is really bad at teaching? (There is only one teacher for the Chemistry SL course, I'm devastated. ) If I do change from SL to HL, I'll have to study more, obviously, HL course ain't that easy, and I'm not ver…
Last reply by Antrikshy, -
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Design lab topic: temperature affecting vitamin c content in orange juice temperatures are 25°C, 35°C, 45°C and 55°C. I am going to be using starch to determine how much drops of iodine needed to oxidize it. Question is: will increasing the temperature affect the results (will it damage the starch n iodine content?) Thank you
Last reply by teboho sefuthi, -
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Hello guys! Can anyone help me with lab-experiment ? I need to investigate one aspect of homologous series, to make design etc. Can anyone give me an example of what I can do about that!! THIS IS SO URGENT!!!!!!!!
Last reply by Ivan Goric, -
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I have a Kinetics Design tomorrow, but no idea of what to do! Please help - ideas welcome!
Last reply by Drake Glau, -
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I need help in calculating the amount of copper oxide from the following equation. Copper sulfate is heated so that it decomposes to copper oxide and sulfur trioxide. How do i calculate the amount of copper sulfate, copper oxide and sulfur trioxide as percentages as not all of the copper sulfate will decompose. I just need a general way to calculate this as it is a part of my design lab report. Thank you for helping me !
Last reply by naksu, -
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Does anyone know where I could find some practice tests similar to the one in the link below, but for other topics? The site I found this one on only has like 3 topics on it. I've tried searching google for "IB SL Chemistry Practice Tests" and everything like that with no luck.
Last reply by DugEFresh77, -
Uncertainity-o-phobia
by Guest Jar Jar D'oh!- 6 replies
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Guys, I'm Sh*t scared of calculating uncertainities, which can probabyl be attributed to my being inexperienced at calculating them, could some one please help by explaining the concept or perhaps if you have some text (.doc/.pdf) that might help! I'm really in bad shape and there's only 2 weeks left to complete labs!
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Hi guys! I just have 2 questions! Hope you could help me out! Does the Molar Volume of a gas assume that all the molecules are of the same size? Since in Neuss's Chem Book, he states that given that pressure, temperature and volume are the same, n=n (moles). But isn't it that some elements are bigger, hence, their pressure will be greater compared to smaller elements given that they have the same number of moles? Please enlighten me on this! Why is it that a gas is most ideal at high temperatures and low pressure? Thanks a lot, guys!
Last reply by Drake Glau, -
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Should I include MLA documentation for an image I found on the interweb This is for my lab report.
Last reply by Sandwich, -
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Hey guys, I am having trouble with my IA. So my question is how does concentration of solution affect the voltage? I am not really getting the central idea. Please help. Thanks.
Last reply by custardapple101, -
Is the research question framed well?
by Guest The Guardian of Asgard- 9 replies
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Hey so I'm confused about the topic. I have two research question and I don't know which one is better. A)How can the heat of hydration of Copper (II) Sulfate be found using Hess’s law ? How effectively can experimental values estimate the heat of hydration of Copper (II) Sulfate as compared to theoretical values? B)How can the heat of hydration of Copper (II) Sulfate be found using Hess’s law ? How effectively can experimental values estimate the heat of hydration of Copper (II) Sulfate as compared to theoretical values? If you're wondering what its about, well basically I performed two experiments that gave me two values of enthalpy changes and using Hess's Law I calcu…
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Drying Calcium chloride
by Guest Jar Jar D'oh!- 7 replies
- 1.2k views
For a lab: 'To investigate the extent to which CaCl2 dissolves in ethanol at varying temperatures' So the extent to which it dissolves is the dry mass of the undissolved salt after 3 minutes. ( This should be an appropriate indicator, but leave any suggestions! ) In the procedure would it be advisable to say "dry the CaCl2 in a hot air oven at 30 Deg C" after filtering it/ the remaining Calcium chloride from solution? I'm not too worried since this website indicates that calcium chloride melts at some 1600 Deg C and then there are toxic chlorine vapors to be wary of, but would the issue arise by using a hot- air oven, that too only at 30 Deg C? Lastly, where in a …
Last reply by dessskris, -
Hello guys. I know that for those taking Chemistry as part of their curriculum this will make you crack up in unstoppable laughter spasms. However, I'm not taking Chemistry, so I'm allowed to ask this (I guess). You'll see, the thin is that I'm taking biology, and have decided to review some interactive lectures I just downloaded. I got to the the tough part involving chemistry, Biochemistry more specifically. and I'm over this weird thing called ion, and proton donors, and acceptors, and lots of non-sense. I'm going mad because I discovered I just cannot skip this topic, since as I advance on the lectures, these basic concepts take more and more relevance, and that's rea…
Last reply by Sandwich, -
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SuPer confusing! Does Chem HL get harder than this ! And I'm still unsure on the type of hybrid onding in strictures
Last reply by carpediem, -
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Please can someone send me an outline or sample of a science Lab Report. A physics one will help too.
Last reply by The Economist, -
Independant variable- 5 variations a must?
by Guest Jar Jar D'oh!- 3 replies
- 719 views
Recently a friend told me that the independent variable must have 5 variations (in her teacher's) and 3 repeats of each variation eg neutralization with 0.5N HCl 3 times, neutralization with 0.6N HCl 3 times etc. My question to you is what do you follow in terms of Number of variations of the independant variable: and number of repeats. Quite obviously this would be to get a 'Complete in the Design: "Developing a method for data collection". Another query is " Do we include a hypothesis for a lab that is solely a Design?" Thanks a lot!
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I was thinking about investigating the kw in different kinds of mineral water.. How would you suggest me to plan my experiment?
Last reply by The Economist, -
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What can be defined as independent variable in the investigation where I was supposed to calculate from graphs enthalpy change of reaction from MgSO4 to MgSO4 * 7H20. This is calculated by mixing with water anhydrous MgSO4 and MgSO4 * 7H20, extrapolating the graphs and using these data. Do I have to define the variables if this will be only assessed for DCP and CE? It is more like bigger exercise, not investigation where I am supposed to find some relationship. Can IA from chemistry be like that?
Last reply by Jeffrey Hein, -
Lab Report Design: What affects ascorbic acid content?
by Guest hellokitty818- 2 replies
- 1.2k views
this is a design lab and it says to design an experiment a factor that affects the ascorbic acid content in fruit juices I have an outline of how to do a chem lab report but i am not sure how to answer this design lab please help
Last reply by Sandwich, -
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hey guys! can you please give me an experiment for kinetics and energetics in chemistry? i really tried hard to find one, but turns out the experiments i found online invloved chemicals not available in the lab.
Last reply by Nachiappan Chochalingam, -
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when we are writing lab reports, we would need to compare the actual value that we get from the experiment that we conducted with the theoretical value, right? some of us might be wondering how to find literature values for enthalpy of neutralisation, especially when Google is not helping. thus, let's share literature values that we have with the sources, so when we need to find it, we can just refer to this thread. here are some that I know:
Last reply by LMaxwell, -
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Hi, I conducted a typical titration lab where I reacted HCl with NaOH. I now want to find the Ka value for HCl. The molarity of the HCl was .1 mol dm-3 and its initial pH was 2.80. Using log, I converted 2.80 to H+ concentration. I know [H+] = [Cl-], yet somehow, I am getting a really low value for ka, which shouldn't be. Any suggestions? Thanks
Last reply by ILM, -
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Cleared up
Last reply by dessskris, -
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EDIT: this has been explained, thanks
Last reply by LMaxwell, -
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Hi I have values like 4 grams, 3g,4g,9g,10g I measured this using kitchen scale. It does not say any uncertainty on the scale 1) So should I include uncertainty in the lab report (+- 1g)??? 2) If you are say do the uncertainty, then I have to calculate the mean for these numbers. What do I do? Do I have to first change uncertainties into percent uncertainties, then add them, then turn them back into absolute uncertainties for the final value??? My kitchen scale rounds rumber to nearest whole number
Last reply by dessskris, -
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Aim: To find out the enthalpy of combustion of series of alcohols Here i have four alcohols, butan-1-ol , pentanol . ethanol and propan-1-ol For butan-1-ol the mass of the lamp was 216.739 the initial temperature of the water was 22 degrees Mass of used lamp was 215.425 final temperature was 42 degrees for pentanol the mass of the lamp was 205.617 initial temperature of water was 22 degrees final temperature was 42 degrees mass of used lamp was 204.255 for ethanol the mass of the lamp was 174.372 the initial temperature of water was 22 degrees final temperature was 42 degrees the mass of the used lamp was 172.680 for propan-1-ol the mass of the lamp was 190.05…
Last reply by kiwi.at.heart, -
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Can I increase the pH by adding water (diluting it) For my IA, I am going to use pepsi. The pH of pepsi is 3. How can I increase the pH? Our blood pH is 7ish. I have to somehow take it to there. Thank you. Chemistry SL
Last reply by Sandwich, -
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I have a few general questions about ib labs and it would be really great if you guys could help me out! 1) If I take the average of three measurements (all with uncertainties of +/- 0.1 mL), does the resulting average have the same uncertainty or would it be +/- 0.3 mL?? 2) Do we need to show little calculations/conversions between mL to L? 3) If my uncertainty is +/- 0.1, then that means a measurement should not be 10.66, but 10.7 right?
Last reply by thebest, -
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The title is pretty self-explanatory, but to make things clearer just in case, I am doing an absorbance lab which deals with calculating the equilibrium constant of FeSCN 2+. Of course, I found some experimental values, and now that I'm done, it's time to do error analysis. Just one problem. I can't find the theoretical/literature value the equilibrium constant. I have searched long and hard. But I can't find it. Maybe I'm stupid with search engines? Anyway, the lab I did was based on the details of this website: http://dwb.unl.edu/c...quilibrium.html Has anyone ever done this lab? My experimental values range from 112-138. I'm pretty sure I did the calculations correctly…
Last reply by CkyBlue, -
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How do u write the formula of two negative ccompounds Eg Phosphorus 5. Chloride Phosphorus 3 chloride How can a group 5 compund have a positive charge?????????
Last reply by ocfx, -
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I have to design a lab for my chemistry sl class. Dissociation: H2CO3 + H2O HCO3− + H3O+ I have to find out how to calculate pKa experimentally ( by doing a experiment 1) Can I do it with acid-base titration? The thing is that H2CO3 is a weak acid. So I was wondering will it work or not. The base will be NaOH? And can I really find the pKa by doing the acid-base titration??? 2) Take a beaker but 20 ml of 1M of H2CO3. Then add water to it. When H2CO solution is made, you can find the pH will a pH meter. Then you can find the concentration of [H+]. This concentration can then go in the formula: Ka = [HCO3−] x [H3O+] / [H2CO3] Then we can make the ICE table (init…
Last reply by Drake Glau, -
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Can anyone be kind enough to breifly explain anything related to periodicity. ? Like.. The oxides and chlorides of period 3 elements Or the concept of electronegativity and affinity And difference between intra molecular and intermolecular forces with examples And THE HL concept as I missed it!!!
Last reply by dandoon96, -
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Hi Aim: find conc. of acetic acid in vinegar Given: NaOH: 50g of NaOH diluted to a 1 dm3 solution (50g + 1L of water) Household vinegar: 35 cm3 35 cm3 vinegar put into a flask and 2-3 drops of phenolphthalein added. using a burette of NaOH solution, added to the vinegar. Results that i got: When added 42 cm3 of NaOH (equilance point reached). How to calculate the concentration of acetic acid? Chemistry SL Thanks a lot.
Last reply by Drake Glau, -
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Hello All I'm doing my lab report about acid base titration I'm attempting to calculate the concentration of given hydrochloric acid....I have two questions regarding this report : 1) Where can I a find a good graphing software to draw relations on graphs, and include uncertainties, error bars, line of best fit and equation of slope...many students use logger pro..but I really can't deal with it..if any one can give me some tips to use it or suggest another graphing software, I would be so thankful. 2) What is the accurate way of calculating uncertainties when taking the average ? For example : (5+-0.2 , 5.3+-0.2 , 5.4+- 0.2) ...how can I calculate the uncertainty of th…
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The image below is the structure of Penicillin....I am wondering that functional group it is for the square thing in the middle Thx!!
Last reply by Drake Glau, -
- 1 reply
- 783 views
Hey guys, we designing a lab to observe equilibrium. Originally I chose to do the dissociation of acetic acid, but the experiment doesn't seem to work or prove anything about equilibrium. Anyone has any suggestions for an equilibrium system that I can observe quantitatively? (measuring the pH, weigh the precipitate.... for example of ways to measure quantitatively)
Last reply by Drake Glau, -
- 1 reply
- 3k views
Hi What are some factors that can affecting experimentally determined pKa of weak acid? I have to do a design lab on this. I am in chemistry sl Thank you
Last reply by Drake Glau, -
- 4 replies
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Hi guys! Well, I was trying to do my chemistry homework, when I suddenly found out that I couldn't decipher how to answer it. It's a page long with super small font, and I don't really know how to proceed. Could you please help me with this one item? 10 cm3 of ethyne is reacted with 50 cm3 of hydrogen to produce ethane according to the equation: C2H2 + 2H2 → C2H6 Calculate the total volume and composition of the remaining gas mixture, assuming that temperature and pressure remain constant. Thank a billion! I'll try to figure out everything else from here!
Last reply by Drake Glau, -
- 2 replies
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What are the best font and sentence space for lab reports?
Last reply by guest, -
- 2 replies
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Hi what will happen in this reaction 2 NaOH + H2SO4 → Na2SO4 + 2 H2O when I increase the concentration of one of the reactants. They form salt and water will a pH of 7. But if I increase the concentration of one of the reactants? will it effect the pH?
Last reply by Keel, -
- 5 replies
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Please help! I need an experiment idea that will produce 2-variable results, is possible with a rather limited supply of chemicals, and is preferably of order 1 or 2. After making the decision to simultaneously complete my Kinetics design lab and Math Studies IA with one experiment and analyzing it separately in each subject area, I realized that I had to find an experiment applicable to both.I have some ideas regarding experiment, such as testing the rate of neutralization for Mg(OH)2 and HCl, but many of them are difficult to quantify. I cannot do calcium carbonate and hydrochloric acid, though they may seem the obvious choice, as I have already used them twice in other…
Last reply by Sabs44, -
- 5 replies
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How many decimal places are final calculated uncertainties supposed to be rounded to?
Last reply by Sabs44, -
Hey Chemistry people. Our teacher has given us the topic 'Predicting the effect of changes in the conditions of a chemical Equallibrium' for one of our design labs, which would be okay, except we've already done a guided lab on the things that affect the rate of reaction (temp. and concentration. I dont know if our school has equipment for pressure) So we're really not sure what else to do on it. I am an awful chemistry student, but even some of the HL kids are at loss. Any idea's on what else we can investigate? Thanks
Last reply by Drake Glau, -
- 11 replies
- 1.7k views
I'm doing a DCP and CE lab report about the factors that affect the rate of reaction; I'm just having issues plotting. I know the volume produced after each interval, and I know the initial concentration. How am I supposed to calculate the concentration throughout the reaction?
Last reply by Sabs44,
