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Wednesday, January 21, 2009

Chemical Formulae & Equations

Mole= Mass/RAM or RMM

Number of particles= mole X Avogadro Constant
(remember, number of atoms, ions and molecules must be identified as the calculation varies)
Example, Number of particles for 1 mole of H2 is 6.02 X 1023 molecules BUT Number of atoms will be 2 X 6.02 X 1023 ( one hydrogen molecule has 2 hydrogen atoms!)

Mass of a substance = Mole X Molar Mass
(Molar mass is calculated as RAM or RMM BUT the Unit is g per mol)

Volume of Gas = Mole X Molar Volume
(For STP, molar volume is 22.4 whereas, for room conditions, molar volume is 24)

X NA X Molar Mass
number of particles ----> mole ----> mass
l
l X Molar Volume
v
Volume of gas

Notes: 1 dm3 = 1000 cm3
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10 comments:

  1. JadzerlJanuary 22, 2009 at 7:13 AM

    I would like to give a comment about this to all of 4sopan..even if u are so pro already in this calculation..u won't be able to survive if u do not know some of the element structures..looks like we all got a lot of memorizing to do yo!!..

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  2. UnknownJanuary 24, 2009 at 12:58 AM

    oxygen - 16. xDD

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  3. ANTJanuary 28, 2009 at 6:16 PM

    happy memorising.... the RAM value will be given in exam hehehe... but.. memorising will help when we learnt the next part of this topic... chemical formulae :D

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  4. ANTFebruary 2, 2009 at 5:13 AM

    how la today's topic: chemical formulae & empirical formula???? ok??

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  5. vgsjzZang!February 7, 2009 at 1:08 AM

    Is okay while I was in class. but I forgot after I back from school. lmao :x

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  6. ANTFebruary 8, 2009 at 3:46 AM

    Who is that? Pls identify urself so I can give evaluation mark.. hehe.. well, when u forgot, u just hav to flip tru ur previous exercises... u'll be able to at least recall a little... happy studying

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  7. JadzerlFebruary 8, 2009 at 8:42 PM

    Its vera,the out shinning girl in the class. Hehe..oww,yah..I got a question to ask though, its about the new topic. What is the state symbol in the equation represent?..I confused by that(on page 49), I see equations with brackets and have s,aq and g in it..what's that?

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  8. c1ov3rFebruary 8, 2009 at 10:16 PM

    RAm???
    Rmm????
    empirical formula????
    molecular formula????
    and blar blar blar~

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  9. ANTFebruary 9, 2009 at 5:03 AM

    Hi Vera.. welcome...
    ok.. the symbol say;
    Mg(s) + O2(g) --> MgO(s)
    Means Magnesium is in the solid state, Oxygen is gas and Magnesium Oxide is also in solid state....
    **aq means aquoues... yet to be learnt... be patient..

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  10. JadzerlFebruary 10, 2009 at 3:25 AM

    okay..^_^

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