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Thread: Chemistry HELP!

  1. #11
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    Quote Originally Posted by DarkSnow View Post
    @Blizzard OMG.. You GENIUS. Thank you so much T_T
    I have a question though, do the forumlas I've highlighted only work when the volume is given in dm-3? Or can they also work when the information is given in cm-3?

    Also, I used the formulas you gave me (which made a lot of sense and I'm wondering why my teacher didn't give us those), for question 6 C and it made a lot of sense (of the same exercise and that I had left blank since I did not understand it), however, I also left question 5 C (ex. 1.5) and I can't figure that one out, could you please help me?
    I can explain but I can't do all of them. Secondly, cm3 will also work with all these formulas, or any unit of volume for that fact, its just that the concentration was given in mol dm-3, so I converted everything to dm3. You have to make sure the units are same before doing ANY calculation.
    [MARINE - COMMODORE] [9.7 RANK] HEI 'TIAN' LONG

  2. #12
    Global Globe globule glob Sanaa's Avatar
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    The percentage composition by mass of a hydrocarbon is C = 85.6% and H = 14.4%.
    (a) Calculate the empirical formula of the hydrocarbon.

  3. #13
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    Quote Originally Posted by DarkSnow View Post
    The percentage composition by mass of a hydrocarbon is C = 85.6% and H = 14.4%.
    (a) Calculate the empirical formula of the hydrocarbon.
    I didn't have to answer that; http://answers.yahoo.com/question/in...5205520AAMLOER If you don't understand just tell me, I will elaborate.
    [MARINE - COMMODORE] [9.7 RANK] HEI 'TIAN' LONG

  4. #14
    Global Globe globule glob Sanaa's Avatar
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    @Blizzard
    What is the mass, in g, of one molecule of ethane, C2H6?

  5. #15
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    Quote Originally Posted by DarkSnow View Post
    @Blizzard
    What is the mass, in g, of one molecule of ethane, C2H6?
    1. Find Molar Mass:
    Mass of C * 2
    Mass of H * 6


    2.
    Mass in g x : Molar Mass
    1 molecule : 6.23 * 1023

    Ans: Mass in g = Molar Mass / 6.23 * 1023

    Solve it and tell me the answer, I'll confirm if it is right or wrong.
    [MARINE - COMMODORE] [9.7 RANK] HEI 'TIAN' LONG

  6. #16
    StrawHat Blitz Ace's Avatar
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    assassin smith


    I remember doing this in year 12... so awesome when you know how to get the answer

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