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Everything posted by ChemSiddiqui

  1. Hi, Which subject apart from your professional one, would you have prefered?
  2. Hi, how your prepare solutions in a laboratory. For example if you have to prepare let say 1.5 mol/dm3 of hydrogen peroxide (H2O2). Any help will be most appreciated!
  3. John Cuthber, thnak you very much, i can not express my gratitude. Yes, u r spot on and this is what i required. Again, thank you very much!
  4. Hi, I heard about this that in electrophlic addition in alkenes, bromine attaches to the end of alkene molecule that have less number of carbon atoms. They were calling it a marconi carb rule sort of thing. If any one knows about it or something similar could you tell me and explain it to me what it is? I would appreciate it!
  5. Thank woelen very much, i appreciate ur explainations!
  6. Thank for that woelen, i understood why limewater is used, but you made no mention of dil.HCl. Would not dil.HCl liberate ammonia as well, if so then why choose limewater than dil.HCl? that is what my question was. thnx anyway!
  7. Hi, i have a few questions. These appeared in an A'level paper and since i am to prepare for my next month exams, i am doing some past papers and i have a few troulbles doing these questions. Any help will be appreciated by who so ever writes in!. 1.Which reagent, when mixed and heated with ammonium sulphate, liberate ammonia? A. aqueous bromine B. dilute Hydrochloric acid C. limewater D. acidified potassium dichromate(VI). Well i thought it was B, dilute hydrochloric acid but the mark schemes say that lime water will release ammonia. How come? Another question is the one concerning esters with its displayed forumla given but i could not attach it because i did not know how to do it. Anyway, i would be greatful if u tell me why limewater and not dil.HCl?
  8. yes YT2095, u defienately r, though i doubt you like to go 2 the franchises in pakistan beacuse if you go to lets say KFC, well u will find the burger too soggy to eat. I don't understand still ppl go there. What a waste of money
  9. Phi for all, i can assure u i have felt no offence at all, though i realised by reading my first reply 2 u my tone was not really merry one, but i apologise for that. I believe that every1 in this forum deserves repect, and i understand i am far to younger than u so i say sorry again. I would love 2 no if u come to pakistan and interact with ppl, and i can assure u that what ever u see in the media about pakistan is clear rubbish but u will hav 2 come to see it.
  10. Well Phi for All, i would like to tell you that the spelling of PAkistan was not delibrately written wrong, u no that that happen while typing.... and by the way why you question every 1s intention every time. but it ok now, i have got ur comment and still i think you ppl need to do some research about Pakistan. Though, rivarly thing really does exsists b/w India and Pakisatn, but that is thanks to the government of both countries, we only want to b friends with them, i went to india and there i was happy to see, ppl really wishing this heated arguments should end.
  11. Hi, I just wanted to know your opinion about Pakisatn. Please give honest opinions, not flattering ones. I can assure you that there will be no offence to any 1 here.
  12. Hi, i would appreciate if any1 can give me a link to a website where i can download experimental videos/clips. I only know youtube but i do think i can go with any other website as well.
  13. No problem at all, we are all humans and can make mistakes. By the as i say if i had any question for my homework i would have never asked because i prefer it the other way by when i don't get something out of my work then my last resort is the science forums because the teachers here are very busy teaching others. Anyway i would apreciate if you could answer me this or just provide with a link to the repective question if you can . Thnx
  14. No not all, its just that i have my A-level exam next month and i and going through some of the past papers and this question about translocation seems to every where and i have not got enough book from which i can find the relevent part for the answer. Anyway, i would have never asked this if this was my homework for college. Thnx anyway, i no u r willing to help
  15. Hi every1, I need to ask you explain the process of translocation with reference to functions of seive tube elements and companion cells. Well alots of people tend to ignore my thread as my Immunity tread is still empty of answer but i need desperate help here. I would apprecitae nay answers
  16. Hi, can anyone answer this 1 please. " DNA replication occurs in cells during interphase before they divide by mitosis. Explain why it is important that replication occurs before mitosis" any help will be most appreciated. Thnx
  17. ChemSiddiqui


    Hi, well this is about immunity ' describe the origin, maturation and mode of action of phagocytes' I know the origin and mode of action but not maturation so please expalin in easy words this. and last question is how the memory cells play a role in long-term immunity. Any help will be most appreciated.
  18. Hi, well i have a few questions to ask so i will number them up. 1. 'The gaseous oxides of nitrogen have positive enthalphy changes of formation. which factors are most likely to make the most significant contribution to these enthalphy changes?' 2. ' There was this question in exam which had 3 options and all three,first and second, second and third or the first only is correct. The question gave a table as. Element X C Si Ge bond length X-X/nm 0.154 0.234 0.244 the question was: Why does the bond length increase down the group? the options were: 1. Orbital overlap decreases down the group 2. Atomic radius increases down the group 3. Nuclear charge increases down the group Now i believe the 2 option is definately correct and 3 is wrong. But i am uncertain about the first.' Please do let me know what you think for an answer with some easy explainations. Your help will be most appreciated.
  19. hi, can any 1 help me out in this : 'An oxygen molecule diffuses directly from the air in an alvelolus to haemoglobin in a red blood cell. What is the minimum number of cell surface membrances through which this molecules must pass?' any help will be most appreciated
  20. Please oblige me with the solution of " Explain the use of Calcium Carbonate as a building material'. I have read a few books about it but there is very little about it so help is required her
  21. Hi IBOOGY, i think you do filtration, titration or ask your teachers back at school, i am sure they'll help yeh.
  22. Hi, can any 1 recommend me a good website from where i can find videoclips of practicals usually involving college level experiments (preferably AS or A level practicals). Any help will be most appreciated!
  23. well it was actually an exam question i was referring to, so i dont know much about it because i myself had problem solving it. i i could find out was the 2 assimilates were sucrose and amino acids. now the question i aslo had 2 name the 2 amino acids so i asked. do you think they may be purine or pyramidines, the amino acids?
  24. the substances that are transported in the process of tranclocation with in a leaf are sucrose and amino acid. what 2 amino acids are they? please help!
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