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  1. Snowflek

    HSC 2017 Chemistry Marathon

    Re: HSC Chemistry Marathon 2017 May someone help me with this question and explain it thoroughly to me? Thank you 1. Explain how the structure and properties of polyethylene and poly(vinylchloride) relate to the way each is used. 2. The structure of a commercially significant monomer is shown...
  2. Snowflek

    Prelim Chem Thread

    Oh lmao... Thank you for explaining.. Im retarded lol
  3. Snowflek

    Prelim Chem Thread

    23.3% magnesium, 30.7% sulfur and 46.0% oxygen So like lets say 100grams again He finds 23.3% of 100grams which is 23.3 grams of mg right?
  4. Snowflek

    Prelim Chem Thread

    I dont get it, all he did was change the percentage to grams. He didnt do anything about the 100 grams? Sorry im very confused atm
  5. Snowflek

    Prelim Chem Thread

    If im not mistaken, the second question is like 100.1 grams. But like i still dont get the point of the grams. All you did was change % to g and then find the moles and divide. Like i dont see you using the 100grams later on
  6. Snowflek

    Prelim Chem Thread

    Hello so i dont get why we should assume its 100g when all you did was just change % to G. Cause like i dont see the 100grams used later on in the question
  7. Snowflek

    Prelim Chem Thread

    Yeah that what i was thinking thanks!
  8. Snowflek

    Prelim Chem Thread

    Thank you for helping me even though you have a cold, really hope you get better :) Im kinda confused at the end though.. So ill go through the steps i did.(This is a multiple choice and the way did it and i did have both different answers but both answers are on the list. My way: I wrote the...
  9. Snowflek

    Prelim Chem Thread

    what mass of silver chloride is obtained by adding excess silver nitrate solution to a 10.0mL volume of 0.10 mol L CacL2 solution?
  10. Snowflek

    Prelim Chem Thread

    Ohh i see thank you
  11. Snowflek

    Prelim Chem Thread

    A 10.0mL volume of 0.10mol CaCl2 solution is diluted to 1.0L using distilled water. What is the concentration of calcium ions, in mol L, in the resulting solution? a) 0.001 b)0.002 c)0.02 D)0.05 I used C1v2=c2v2 and i did 0.10x10/990 =0.00101010101 so i got a, is it correct? Sorry if its a dumb...
  12. Snowflek

    Prelim Chem Thread

    Thank you so much!
  13. Snowflek

    Prelim Chem Thread

    Can someone help me with this question? Which process requires the largest energy input for a given mass of water? A) Melting B) Heating to boiling point C) vaporisation to steam D)electrolysis I was thinking B but not too sure D: Which of the following is an element that shows valencies of 3...
  14. Snowflek

    Prelim Chem Thread

    Thank you!
  15. Snowflek

    Prelim Chem Thread

    Hello, i need some assistance with this question. So i asked my teacher and she said use the c1v1=c2v2 method. How do we know if we use this formula? Cause for some reason i was thinking about the c=n/v 13. A student takes 10 mL of a 0.45M solution and adds 990 mL. What will the new...
  16. Snowflek

    99.95

    Hey guys so i thought only 1 person can acheive a mark and i heard around 50 people got like 99.95 atar. I don't understand how this thing work, since its a rank then does it mean those 50 people who got 99.95 are all 1st in the state? And all their subjects aligned together makes them all first?
  17. Snowflek

    Prelim Chem Thread

    Yep ok :D Thanks for your help from the previous question :D
  18. Snowflek

    Prelim Chem Thread

    Calcium bromide and sodium sulfate react in solution and a precipitate of calcium sulfate forms. In a certain experiment the mass of calcium sulfate formed in this reaction was calculated to be 0.80g a) Write a balanced equation for this reaction: CaBr2 + Na2SO4 ---> CaSO4 + 2NaBr (correct me if...
  19. Snowflek

    Prelim Chem Thread

    OO!!! i see! thank you for the good explanations!!! If you are free can you solve one more question for me?
  20. Snowflek

    Prelim Chem Thread

    Do we not do like 0.085 x ((207.2 x 3) + (32.07 x 3) + (16 x 3 x 4)) right? Like what i added in was the mole ratio to it
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