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UnbelievableDreams

  • one year ago

Chemistry question

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  1. UnbelievableDreams
    • one year ago
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    How many atoms of hydrogen are contained in each of the following? 1) 48 molecules of CH3CH2COOH 2) 4.54 mol H3PO4 3) 30 g C6H5ONH

  2. anonymous
    • one year ago
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    Q1: Suppose the question would be for 1 molecule can you calculate the # H atoms? Q2: Do you know how many atoms are in 1 mol? Q3: Can you convert from grams to moles?

  3. UnbelievableDreams
    • one year ago
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    @LeibyStrauss I am confused because I missed the class.

  4. anonymous
    • one year ago
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    I'll try to help, but I can't replace a whole class in these short posts. I'll reference each post with Q1, Q2, Q3 when replying please do the same. For Q1: \[CH _{3}CH _{2}COOH\] Let's start with something simpler. Do you know how many H's (hydrogen's are in \[H _{2}O\]

  5. UnbelievableDreams
    • one year ago
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    2?

  6. UnbelievableDreams
    • one year ago
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    @LeibyStrauss

  7. anonymous
    • one year ago
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    So how many H atoms are in CH3CH2COOH?

  8. UnbelievableDreams
    • one year ago
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    6?

  9. anonymous
    • one year ago
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    Correct. This though, is just for one molecule, it needs to be multiplied by the # of molecules in the example.

  10. anonymous
    • one year ago
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    Q2: Look in you textbook or google, how many atoms are in a mole or look / search for Avogadro's numv\ber. A mol btw is is just a quantity number, just like a dozen is just the number 12. A dozen eggs and a dozen doughnuts, both mean that you have 12. The mol is same thing.

  11. UnbelievableDreams
    • one year ago
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    So it is 6.022 x 10^23

  12. anonymous
    • one year ago
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    Re: Q1 are you good with the first question?

  13. UnbelievableDreams
    • one year ago
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    Yes. Question one is 288

  14. anonymous
    • one year ago
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    Re: Q2 You are correct. I'm blacking out for a moment. I think 1 mol of H3PO4 would be (since there are 3 H's) 3*6.022*10^23. Since there are 4.54 mol it should be (3)(4.54)(6.022)*10^23. Can someone verify that this is correct?

  15. anonymous
    • one year ago
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    You are correct re: Q1

  16. anonymous
    • one year ago
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    Re: Q3. You need to convert from grams to moles and do the same as you did for Q2. Do you know how to convert from grams to moles?

  17. UnbelievableDreams
    • one year ago
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    Not really.

  18. anonymous
    • one year ago
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    Ok. In short it's called dimensional analysis KhanAcademy.org has good videos on it and practice skills. You need to start with whats given, in this case 30 g C6H5ONH. Then set up your equation so that grams cancel each other out and you are left with moles. You need to calculate the molar mass, also know as g/mol, or grams per mole of C6H5ONH and plug the gram value in the denominator (where grams is written). The molar masses are on the periodic table \[30gram C6H5ONH * \frac{1 mole }{grams }\] Following this equation will give you the # of moles

  19. UnbelievableDreams
    • one year ago
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    30/108.10 is .27750

  20. anonymous
    • one year ago
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    It looks correct. I only used 2 sig figs so I got 108. 0.27750 is the # of moles. Find out if your professor / teacher is pick with significant figures. If yes, then since 30 is 2 sig figs you need to round to 0.28. Did what I post regarding the 2nd question make sense?

  21. UnbelievableDreams
    • one year ago
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    30(14)(6.022 x 10^23) / 0.28 = 9.03e+26

  22. anonymous
    • one year ago
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    I'm not sure why your using 30(14). In C6H5ONH there are 6 H's. So I think we have: For 1 mole: 6(6.022)x10^23 Since there are 0.28 mol 0.28(6)(6.022)x10^23. My brain has over-trained tonight and I may be making a mistake.

  23. UnbelievableDreams
    • one year ago
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    I got it. Thank you so much. I understood perfectly. :)

  24. anonymous
    • one year ago
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    You're welcome.

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