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mariadelia27

  • one year ago

A 10 gram sample of a substance that's used to detect explosives has a k-value of 0.1353. Find the subtance's half-life, in days.round to the nearest hundreds

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  1. RaphaelFilgueiras
    • one year ago
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    you shoud try to ask it in chemistry section

  2. mariadelia27
    • one year ago
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    ok thanks it scause i really need this answer

  3. RaphaelFilgueiras
    • one year ago
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    do you have the formula?

  4. mariadelia27
    • one year ago
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    n=Noe^kt

  5. RaphaelFilgueiras
    • one year ago
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    n is moles?

  6. mariadelia27
    • one year ago
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    i need to round to the nearest hundreds too

  7. RaphaelFilgueiras
    • one year ago
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    what is the unity of k?

  8. swissgirl
    • one year ago
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    What does k represent?

  9. mariadelia27
    • one year ago
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    a positive constant that depends on the substance itself and on the units used to measure time

  10. RaphaelFilgueiras
    • one year ago
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    5=10*e^(Kt), but what unity of time? seconds^-1?

  11. swissgirl
    • one year ago
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    Its in days

  12. mariadelia27
    • one year ago
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    there a picture of the question

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  13. RaphaelFilgueiras
    • one year ago
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    and probally the formula is e^(-kt)

  14. mariadelia27
    • one year ago
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    did you see the picture

  15. swissgirl
    • one year ago
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    ya its a diff question :)

  16. mariadelia27
    • one year ago
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    my bad ill got teh wrong one

  17. RaphaelFilgueiras
    • one year ago
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    if k is in days^-1 just solve 5=10*e^(-kt), and you will find t

  18. mariadelia27
    • one year ago
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    but i dont know how to solve it either -.-

  19. mariadelia27
    • one year ago
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    can you help me please i really need it

  20. RaphaelFilgueiras
    • one year ago
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    ok

  21. RaphaelFilgueiras
    • one year ago
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    |dw:1372309018511:dw|

  22. mariadelia27
    • one year ago
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    so the answer is 0,5

  23. mariadelia27
    • one year ago
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    its exponoential decay thats the section were doing

  24. RaphaelFilgueiras
    • one year ago
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    5.12303

  25. RaphaelFilgueiras
    • one year ago
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    k=0.1353

  26. RaphaelFilgueiras
    • one year ago
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    i use that k

  27. mariadelia27
    • one year ago
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    yeah k is that

  28. mariadelia27
    • one year ago
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    0.1353

  29. mariadelia27
    • one year ago
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    it said its wrong -.-

  30. RaphaelFilgueiras
    • one year ago
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    we have to know thr unity of k

  31. swissgirl
    • one year ago
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    What did you put the answer as?

  32. swissgirl
    • one year ago
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    sorry I am not making sense. What did you enter as your answer?

  33. mariadelia27
    • one year ago
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    5.12303

  34. swissgirl
    • one year ago
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    Its to the hundredths place so it should be 5.12

  35. RaphaelFilgueiras
    • one year ago
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    try 1871.15 days

  36. RaphaelFilgueiras
    • one year ago
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    im supposing k is in years

  37. swissgirl
    • one year ago
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    Ohhhh yaaaaa that makes more sense actually

  38. mariadelia27
    • one year ago
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    just that its 53% not 51 %

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  39. mariadelia27
    • one year ago
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    this is another question can you guys help with this one

  40. mariadelia27
    • one year ago
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    please i did it

  41. mariadelia27
    • one year ago
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    please !

  42. mariadelia27
    • one year ago
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    you guys help me i really did to passs this class tomorrow is my last day

  43. mariadelia27
    • one year ago
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    are you guys there ?

  44. mariadelia27
    • one year ago
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    heeelp anyone

  45. RaphaelFilgueiras
    • one year ago
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    6733.44 years

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