Lilasko Posted October 1, 2012 Share Posted October 1, 2012 Yes, that's probably right! AHH.(Can you be my adoptive chemistry teacher? ) Haha Sure, I would love to Link to comment Share on other sites More sharing options...
Ellenowl Posted October 3, 2012 Share Posted October 3, 2012 Anybody any good at Chemistry? I thought I was ok, but I'm in a pickle!What is the difference between Mr and RAM (relative atomic mass)? I thought there wasn't any, but there seems to be one, and it relates to finding the molecular formula from the empirical formula, as well as other stuff. Also, I'm stuck on questions like this: Nickel combines with carbon monoxide to form nickel carbonyl, Ni(CO)x ( x is subscript like in H2O). When 2.95g Nickel was heated with carbon monoxide,it was converted completely into 8.55g nickel carbonyl. Find the mass of CO which combined with 2.95g Ni and hence find the value of x in the formula. I made a little equation: 2.95g+CO->8.55g so CO=5.6g And the Mr (arghh!) of CO is 12+16=28 Then I put it into the equation no. of moles= mass/Mr so then 5.6/28=x but this is not going to be a nice integer value that would be the right answer and I cannot see where I went wrong. I had the same issue with the next question I tried, so I think the problem is with my method. Anybody know what to do? Thanks for reading this. It's quite long. Link to comment Share on other sites More sharing options...
Lilasko Posted October 3, 2012 Share Posted October 3, 2012 Anybody any good at Chemistry? I thought I was ok, but I'm in a pickle!What is the difference between Mr and RAM (relative atomic mass)? I thought there wasn't any, but there seems to be one, and it relates to finding the molecular formula from the empirical formula, as well as other stuff. Also, I'm stuck on questions like this: Nickel combines with carbon monoxide to form nickel carbonyl, Ni(CO)x ( x is subscript like in H2O). When 2.95g Nickel was heated with carbon monoxide,it was converted completely into 8.55g nickel carbonyl. Find the mass of CO which combined with 2.95g Ni and hence find the value of x in the formula. I made a little equation: 2.95g+CO->8.55g so CO=5.6g And the Mr (arghh!) of CO is 12+16=28 Then I put it into the equation no. of moles= mass/Mr so then 5.6/28=x but this is not going to be a nice integer value that would be the right answer and I cannot see where I went wrong. I had the same issue with the next question I tried, so I think the problem is with my method. Anybody know what to do? Thanks for reading this. It's quite long. Just one question, x isn't the same as no. of moles? Link to comment Share on other sites More sharing options...
astor Posted October 3, 2012 Share Posted October 3, 2012 Anybody any good at Chemistry? I thought I was ok, but I'm in a pickle!What is the difference between Mr and RAM (relative atomic mass)? I thought there wasn't any, but there seems to be one, and it relates to finding the molecular formula from the empirical formula, as well as other stuff. Also, I'm stuck on questions like this: Nickel combines with carbon monoxide to form nickel carbonyl, Ni(CO)x ( x is subscript like in H2O). When 2.95g Nickel was heated with carbon monoxide,it was converted completely into 8.55g nickel carbonyl. Find the mass of CO which combined with 2.95g Ni and hence find the value of x in the formula. I made a little equation: 2.95g+CO->8.55g so CO=5.6g And the Mr (arghh!) of CO is 12+16=28 Then I put it into the equation no. of moles= mass/Mr so then 5.6/28=x but this is not going to be a nice integer value that would be the right answer and I cannot see where I went wrong. I had the same issue with the next question I tried, so I think the problem is with my method. Anybody know what to do? Thanks for reading this. It's quite long. As I understand it, Mr is the RAM(I guess this is the same as Ar?) of all the elements in the compound added together. So it basically means the same thing, but Mr is used when it is talking about compounds, and RAM is elements. I assume you're doing AS level too as I am on this as well. I asked the teacher about the values being ridiculous and she said it isn't like GCSE when they all come to satisfactory numbers, it can be a bit random and you have to use 3 sig figs. However I didn't check the question or your working, so can't say anything else. Sorry Link to comment Share on other sites More sharing options...
astor Posted October 6, 2012 Share Posted October 6, 2012 Similaraties and differences between the structure of amino acids and nucleotides? Link to comment Share on other sites More sharing options...
Lilasko Posted October 6, 2012 Share Posted October 6, 2012 Similaraties and differences between the structure of amino acids and nucleotides? Oh we studied this, but I didn't listen Link to comment Share on other sites More sharing options...
astor Posted October 6, 2012 Share Posted October 6, 2012 Oh we studied this, but I didn't listen It's ok, I found the mark scheme buried online. Not cheating. Just resourceful. (But I might need chemistry help later ) Link to comment Share on other sites More sharing options...
Lilasko Posted October 6, 2012 Share Posted October 6, 2012 It's ok, I found the mark scheme buried online. Not cheating. Just resourceful. (But I might need chemistry help later ) Exactly xD Sure, I'm here Link to comment Share on other sites More sharing options...
Ellenowl Posted October 10, 2012 Share Posted October 10, 2012 Sorry. I have another chemistry question: If one took all of the elements in period 3 (across not down) and ionised them so that they had exactly the same number of electrons, how would their radius (radii?) differ and why? I think it has something to do with the atomic or mass number, but I missed the lesson so I'm confused, and I have a test tomorrow. Anybody know about this? Link to comment Share on other sites More sharing options...
astor Posted October 10, 2012 Share Posted October 10, 2012 Sorry. I have another chemistry question: If one took all of the elements in period 3 (across not down) and ionised them so that they had exactly the same number of electrons, how would their radius (radii?) differ and why? I think it has something to do with the atomic or mass number, but I missed the lesson so I'm confused, and I have a test tomorrow. Anybody know about this? The greater the atomic number, the smaller the radius. This is because there are more protons when there is a greater atomic number, giving the nucleus a greater positive pull towards the electrons, so they come closer to the nucleus. Because they are all in the same period, with the same number of electrons, there aren't any other factors which will outweigh this (eg. shielding blah blah) Does that make sense? Link to comment Share on other sites More sharing options...
Ellenowl Posted October 10, 2012 Share Posted October 10, 2012 The greater the atomic number, the smaller the radius. This is because there are more protons when there is a greater atomic number, giving the nucleus a greater positive pull towards the electrons, so they come closer to the nucleus. Because they are all in the same period, with the same number of electrons, there aren't any other factors which will outweigh this (eg. shielding blah blah) Does that make sense? Thanks so much! That does make sense and now I can go to bed without worrying about it. I think my friend wrote it down wrong, so when I copied it up, it made no sense. Wow! You've made it seem really simple. Thank you again! Link to comment Share on other sites More sharing options...
astor Posted October 11, 2012 Share Posted October 11, 2012 Thanks so much! That does make sense and now I can go to bed without worrying about it. I think my friend wrote it down wrong, so when I copied it up, it made no sense. Wow! You've made it seem really simple. Thank you again! No problem, I know very well how it feels to panic about not getting chemistry (the rule only applies for the same period, by the way. Across a period = smaller, down the group = bigger) Link to comment Share on other sites More sharing options...
BiaIchihara Posted November 19, 2012 Share Posted November 19, 2012 (edited) Hello, I'm doing a college work about urbanistic studies of a city (it can be any city in the world apart of mine) and the city I've chosen was Toyota, Japan. The deadline is December 3rd and most of this is done, so I'm not asking to do the work for me, just to some japanese speaker translate some texts from japanese to english (thanks to Eriko for sending to me ), so I can translate to portuguese and put on that It's 3 texts and they aren't that long, they talk about ancient and medieval history and general characteristics of the city. I'm asking to someone since I can't count on Google Translator because it messes everything up I looked for other people to help me, but pratically none could help me (one was too busy to do that, another one charged a lot of money - R$ 80,00, around 40 US dollars - to translate these texts and other two didn't answer the message I gave them so far). Anyone able to give me a hand can contact me by FB inbox, Twitter, PM, anyway you want to Thanks in advance and sorry for bothering because of this work EDIT: didn't attach the files, cause their sizes exceed the maximum to put here Edited November 19, 2012 by BiaIchihara Link to comment Share on other sites More sharing options...
BiaIchihara Posted November 23, 2012 Share Posted November 23, 2012 Hello, I'm doing a college work about urbanistic studies of a city (it can be any city in the world apart of mine) and the city I've chosen was Toyota, Japan. The deadline is December 3rd and most of this is done, so I'm not asking to do the work for me, just to some japanese speaker translate some texts from japanese to english (thanks to Eriko for sending to me ), so I can translate to portuguese and put on that It's 3 texts and they aren't that long, they talk about ancient and medieval history and general characteristics of the city. I'm asking to someone since I can't count on Google Translator because it messes everything up I looked for other people to help me, but pratically none could help me (one was too busy to do that, another one charged a lot of money - R$ 80,00, around 40 US dollars - to translate these texts and other two didn't answer the message I gave them so far). Anyone able to give me a hand can contact me by FB inbox, Twitter, PM, anyway you want to Thanks in advance and sorry for bothering because of this work EDIT: didn't attach the files, cause their sizes exceed the maximum to put here *bump* Link to comment Share on other sites More sharing options...
qwurtie Posted December 29, 2012 Author Share Posted December 29, 2012 the circled one is the one i need help with if you need the answers, to work backwards, i can post those also..... Link to comment Share on other sites More sharing options...
Lilasko Posted December 29, 2012 Share Posted December 29, 2012 the circled one is the one i need help with if you need the answers, to work backwards, i can post those also..... Would love to help, but I don't know what a hydrazine molecule is Link to comment Share on other sites More sharing options...
astor Posted December 29, 2012 Share Posted December 29, 2012 I did this question yesterday but I didn't get it either Link to comment Share on other sites More sharing options...
astor Posted December 29, 2012 Share Posted December 29, 2012 Hang on, is it doable if you just forget about the blah blah hydrazine formula and just work out a H N H bond? Is the answer 107 degrees? Link to comment Share on other sites More sharing options...
qwurtie Posted December 29, 2012 Author Share Posted December 29, 2012 Hang on, is it doable if you just forget about the blah blah hydrazine formula and just work out a H N H bond? Is the answer 107 degrees? ya, it is...but where does the third atom around the nitrogen atom come from? D:the first bit says 'hydrazine, N2H4' ugh, this is so frustrating, i thought i knew stuff but doing these papers i dont know anything dasdjkdfjh, Link to comment Share on other sites More sharing options...
eloise.shaw Posted December 29, 2012 Share Posted December 29, 2012 Bloody hell, I don't want to take chemistry at A level. Link to comment Share on other sites More sharing options...
qwurtie Posted December 29, 2012 Author Share Posted December 29, 2012 Bloody hell, I don't want to take chemistry at A level. Dont. Link to comment Share on other sites More sharing options...
astor Posted December 29, 2012 Share Posted December 29, 2012 The third free electron must be bonded to the other Nitrogen yus. Link to comment Share on other sites More sharing options...
qwurtie Posted January 4, 2013 Author Share Posted January 4, 2013 The third free electron must be bonded to the other Nitrogen yus. thats what i thought BUT THEY SHOULD MAKE IT MORE CLEAR smh lol thanks # what colour cyclohexane goes when Br2 is added to Cl- Link to comment Share on other sites More sharing options...
qwurtie Posted January 4, 2013 Author Share Posted January 4, 2013 that was my next q btw, not just in reply to mair what colour does cyclohexane goes when Br2 is added to Cl- ? Link to comment Share on other sites More sharing options...
astor Posted January 4, 2013 Share Posted January 4, 2013 Cl is more oxidising than bromine (is it?)... Sooooo the chlorine stays in ion form because the bromine can't displace it. Sooo the cyclohexane only notices the Bromine so turns orange I think. Do you agree? Ugh hibaaaaaa biology hahahshshjchmbv. Link to comment Share on other sites More sharing options...
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