Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculation problem

  1. Jan 26, 2005 #1
    Hi!
    How many per cent of silicon is there in a silicate mineral, if 0.567 g during analysis gave 0.484 silicon oxide.

    Gratefull,
    Danne
     
  2. jcsd
  3. Jan 26, 2005 #2

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    danne,

    We really can not help you unless you first make an attempt. What ideas do u have ?
     
  4. Jan 27, 2005 #3
    Oh, I'm sorry. But I've not any cloue.
     
  5. Jan 27, 2005 #4

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Okay.
    [tex] percentage \ Si =\frac{m_{Si}}{m_{compound}}\cdot 100 [/tex]

    Daniel.
     
  6. Jan 27, 2005 #5

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Ask yourself : how much Si is there in SiO2 ?
     
  7. Jan 27, 2005 #6
    Okej, I've: % Si = Si:Si02 * 100 = 2800:60 ~= 47%

    So the weight information's only purpose is to trick you? :(
     
  8. Jan 27, 2005 #7

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    No,its purpose is to help answer the problem's question.Reread its text and see what it needs to be done.

    Daniel.
     
  9. Jan 27, 2005 #8
    (0.567 * Si * 100):(0.484 * Si02) = (56.7 * 28):(0.484 * 60) = 1588:29.04 ~= 55%
    Sorry for the amount of numbers, I'm using log-table.
     
  10. Jan 27, 2005 #9

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    I'm sorry,u have no reason to applogize,even after coming up,again,with a wrong answer.

    My answer is "roughly 40%".

    Daniel.
     
  11. Jan 27, 2005 #10
    What's the unit of .484 ? grams?
     
  12. Jan 27, 2005 #11

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    No,MeV/c^{2}... :tongue:

    Daniel.
     
  13. Jan 27, 2005 #12
    alright... I don't get 40 % when i try this problem out.

    SiO2 = total weight

    SiO =.484 grams

    O = Total weight - .484 + (weight of O inside Silicon oxide)

    Well we know how much Oxygen is in there we can easily figure out the percentage of Si....

    I don't get 40 %... I think you've mistaken SiO for SiO2 (silicon oxide not dioxide)
     
    Last edited: Jan 27, 2005
  14. Jan 27, 2005 #13

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Of course it's [itex] SiO_{2} [/itex].

    Daniel.

    P.S.Does Silicium form oxides at +2??My guess is "no"...
     
  15. Jan 27, 2005 #14
    % Si = (0.567 * Si * 100):(0.484 * Si*Si02) = (56.7 * 28):(0.484 * (28 + 28 + 2 * 16)) = 1587.6:(0.484 * 88) = 42.59%

    Yes!! At least my slow head isn't act as a fools mind.
     
    Last edited: Jan 27, 2005
  16. Jan 27, 2005 #15

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Explain that part:
    [tex] (28+28+2*16) [/tex]

    Why on Earth did u add 28 TWICE???

    Daniel.

    P.S.Is it [tex] Si_{2}O_{2} [/tex] ??
     
  17. Jan 27, 2005 #16
    I add the Si and Si02 together.
    Edit: Which seems to be quite idiotic now...
     
    Last edited: Jan 27, 2005
  18. Jan 27, 2005 #17
    Can I have some more hint?
     
  19. Jan 27, 2005 #18

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Why would you do that for???It's only SiO_{2} in the mineral.It has the molecular mass of 60 and it's content of Si is
    [tex] \frac{28}{60} [/tex]

    Is that enough ?

    Daniel.
     
  20. Jan 27, 2005 #19
    No. I can't solve it.
     
  21. Jan 27, 2005 #20

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Okay.Here goes:
    28g Si---------------------------->60g SiO_{2}
    x g Si------------------------------>0.484g SiO_{2}

    Find "x" and then:

    x g Si-------------------------->0.567g mineral
    y g Si-------------------------->100g mineral

    Find "y".That will be the answer to your problem
    "y"% Si in the mineral...

    Daniel.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Calculation problem
  1. Calculating Pressure (Replies: 2)

  2. Calculate %assay (Replies: 2)

  3. Calculating ksp (Replies: 1)

Loading...