27.0 L of HCl gas at STP is dissolved in water, giving 785 mL of solution. What is the molarity of the HCl solution?

Question

    9.46 M

    1.53 M

    0.946 M

    15.3 M

    None of the above is within 1% of the correct answer.

Answer 1

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(27.0 L) / (22.4 L/mol) / (0.785 L) = 1.5355 mol/L

So choose the second option.

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Answer 2

27 L of HCl is just over 1 mole (1 mole of any ideal gas at STP occupies 22.4 L)

You can look at the choices and pick the second without pulling out the calculator.

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• zeniyah8 months agoReport

  thank you very much for your help
  

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Answer 3

27 liters at STP.  At STP, 1 mole of gas occupies 22.4 Liters of space.

27/22.4 = # of moles of HCl gas.  You dissolve this in 785 mL, so how many moles would you need for 1 liter?

k / (27/22.4) = 1000 / 785

k = (1000/785) * (27/22.4)

k = 27000 / (22.4 * 785)

k = ‭1.5354868061874431301182893539581‬...

1.53 M would work

• zeniyah8 months agoReport

  thank you
  

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