hypervalent_iodine

Your math seems fine. There's nothing you can do about it if that's what the results are giving you. What did you use to determine the end point?

Yep! The short story is that you need to know the total number of moles of HCl you have in the flask. You perform two reactions with the same volume of HCl, so the total number of moles is equal to the number of moles used in the first reaction plus the number of moles used in the second. The two reactions: 1. In your experiment the first thing that you do is the reaction you wrote out above. You mix HCl with Na2CO3, and you make NaCl, CO2, and water. You assume that you used up all of the Na2CO3 in the initial reaction, and that there was an excess of HCl (do you know what I mean by this?). The number of moles of HCl used up will be equal to half the number of moles of Na2CO3 that reacted, based on the stoicheometric equivalents in your chemical equation. 2. You then have some HCl left over that wasn't able to react with the Na2CO3 (otherwise you wouldn't have titrated with NaOH), and you react this with NaOH until all of the HCl is gone. Do you know the chemical equation for this reaction? To help illustrate what I am getting at, consider a case similar to yours where you have 1 g of Na2CO3 in a flask. This is equal to .0095 moles of Na2CO3. To this we add 50 mL of a 1M HCl solution. In that 50 mL there is 0.05 moles of HCl. Based on the stoicheomtry of the equation, if all of the Na2CO3 were to react, it would need 0.019 moles of HCl. This is less than the amount of HCl that we have available, so all of the Na2CO3 will react and 0.031 moles of HCl will be left unreacted. If we then want to check how many moles of HCl is left, we could titrated against NaOH to react what was remaining. Let's say we do the titration with 1M NaOH. Given that there is 0.031 moles of HCl left, if you did the titration would find that you would need on average, 31 mL of 1M NaOH to get to the end point and react with all the HCl available. Working backwards, if we didn't know what the concentration of HCl was, we could figure out that in the first reaction with Na2CO3 we needed 0.019 moles, and in the second reaction with NaOH we needed 0.031 moles. Thus the total number of moles in the 50 mL of HCl we added is 0.031 + 0.019 moles, which is 0.05 moles. The concentration is therefore 0.05 moles / 0.05 L, which of course equals 1M. Does that make sense?

! Moderator Note This is going directly to the trash. If you have science to discuss, by all means open a new topic in Speculations.

Can you give an equation for the reaction between the two? As in A + B --> C + D not a mathematical equation

Your first calculation isn't going to work. The entire point is to standardise the HCl, so you're supposed to work it out based on the NaOH titration. You have two things going on here; a reaction between the Na2CO3 and HCl, and a reaction between whatever HCl didn't react and the NaOH. The idea is that you are supposed to react all of the Na2CO3 with only some of the HCl (ie. there is excess HCl and limited Na2CO3 available). This leaves a certain number of moles if HCl left available to react, so you use the NaOH for this part. The number of moles of HCl is therefore a combination of the moles used in both reactions, not just the one. Honestly, this seems like a pretty silly way to standardise anything (why not just titration with NaOH?), but that's neither here nor there I guess. The C1V1=C2V2 is not a great calculation in this instance because you have two things going on. In a normal titration it would work fine, but not this one. Forget about the dilution. You didn't dilute any of the stocks prior to combining them, so it doesn't matter. All you need to work with is moles and the original volumes that you added.

Okay, so what are your attempts? What equations have you been using? Could you also clarify for me the first table. Are you adding the HCl to the Na2CO3 and then the NaOH to that solution once it finished reacting? What does he [HCl] used refer to exactly? Used in which bit?

! Moderator Note We require that you present your discussion here, not demand members to go off-site to understand what you're on about. I have removed your eBay links and reference to your unit. You are not permitted to use this site for advertising. Finally, as you are presenting what amounts to speculation, I have moved the thread to Speculations. You must adhere to the rules of this forum, as well as the general rules of SFN.

If this is homework, you need to make some attempt at the questions. What equations have you learned so far?

Definitely some of my best work.

Hold up, I still don't understand what you're doing exactly. Can you paste the exact procedure and any preamble? To clarify: I understand the concepts, but what you've relayed in terms of procedure is a bit unclear to me.

Any number of reasons. What factors do you know of that might affect equilibrium? How did you do the extraction?

! Moderator Note waitforufo, Could you possibly offer some points you wish to discuss? Currently, this thread looks like little more than an attempt at soap boxing.

If that were the case, the batteries wouldn't constantly 'burn out.'

I believe (but am not 100% sure) they can't evolve if all new individuals come from cuttings of the parent. They would be genetically identical.

If you are using up batteries to power your perpetual motion device, then it's not a perpetual motion device.

I'm a little confused. In another thread you indicated you already had an idea you wanted to patent?

Are you suggesting we artificially engineer a female of the species? The problem with that - as I understand it - is that we would need to know what the genome of a female looked like first. As we don't have a female with which to study its genome, the task is more or less impossible. It doesn't seem necessary though, as we can grow male clones and continue the species from cuttings.

! Moderator Note Roger Dynamic Motion, Do not hijack this thread with your own speculations. I have hidden your more recent posts. Any others will also be hidden and you will receive an official warning.

! Moderator Note Sorry, I wasn't necessarily referring to the posts directly prior to the last note. I am satisfied that those posts are on topic. I was more hinting at the posts about rapes and the breakdown of U.K. society. Scherado, whether you authored this thread or not, we have standards and rules that you agreed to obey upon signing up. We expect that the topic of a thread is what is outlined in the title and OP. Anything more is considered off topic, for the purposes of keeping discussion focussed. If you wish to discuss other things, please start other threads.

! Moderator Note Just a reminder for members to please stick to the topic. That includes the author of the thread as much as anyone else participating.

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! Moderator Note A few things. Firstly, your use of language - specifically your use of the word retarded - needs to change. Secondly, the rules of this forum specifically prohibit members from slurring an entire group of people as you have done. If you can't contribute anything intelligent (or additive at the very least) to the discussion, I would ask that you don't bother contributing.

I think you're pretty much correct, though you could leave out the stuff about the octet. You could also make an argument about atomic size, but it amounts to the same thing.

I am not sure there is anyone here working in computer science. You might like to try and contact your local university? Look through their department list and email a few people who seem relevant.