Chemistry

The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times. A basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood.

Luminol has a molecular weight of 177g/mol

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 14.0 of luminol into a total volume of 75.0 of .

1. What is the molarity of the stock solution of luminol?
ANSWER:molarity of luminol solution =1.05
2.Before investigating the scene, the technician must dilute the luminol solution to a concentration of 6.00×10−2 . The diluted solution is then placed in a spray bottle for application on the desired surfaces.

How many moles of luminol are present in 2.00 L of the diluted spray?
ANSWER: moles of luminol =0.120

3.What volume of the stock solution (Part A) would contain the number of moles present in the diluted solution (Part B)?

Answer: needs to be in mL and i cant figure it out. Can someone please help

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  1. The density of a 22.0% by mass ethylene glycol (C2H6O2) solution in water is 1.03 g/mL. Find the molarity of the solution.

    Answer in M

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  2. # of moles of solute
    Molarity = --------------------
    Liters of solution

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  3. I'm confused by the luminol question.
    First, 14 g in 75.0 what unit. If that is 75 mL, then the answer of 1.05 M is correct.
    Second, 6.00 x 10^-2 what? If that is molar, then no matter how it was diluted, your answer of 0.120 M is correct.
    Third, how much volume? Is that the 2 L of solution from part B? If so then 1.05M x ? L = = 0.120 moles and solve for liters and convert to mL. If it isn't 2L, then supply the correct value.

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  4. For the ethylene glycol solution.
    The density is 1.03 g/mL. How much will a liter of the solution weigh? That will be
    1.03 g/mL x 1000 mL = 1030 grams.
    How much of that is ethylene glycol. 22%? So how much with the ethylene glycol weigh? That will be 1030 x 0.22 = ??
    How many moles is that?
    ??/molar mass ethylene glycol = xx
    molarity = xxmoles/L solution.

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  5. Sorry about that

    The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times. A basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood.

    Luminol has a molecular weight of 177g/mol

    The forensic technician at a crime scene has just prepared a luminol stock solution by adding 14.0 of luminol into a total volume of 75.0 mL of H2O.

    1. What is the molarity of the stock solution of luminol?
    ANSWER:molarity of luminol solution =1.05 M

    2.Before investigating the scene, the technician must dilute the luminol solution to a concentration of 6.00×10−2 . The diluted solution is then placed in a spray bottle for application on the desired surfaces.

    How many moles of luminol are present in 2.00 L of the diluted spray?
    ANSWER: moles of luminol =0.120

    3.What volume of the stock solution (Part A) would contain the number of moles present in the diluted solution (Part B)?

    Answer: needs to be in mL and i cant figure it out. Can someone please help

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  6. see above.

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  7. It pretty simply really. All you have to do is use the same formula that you would to convert the weight of a snail into light years.

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  8. 144 ml

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  9. 114

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  10. Steiger nei von streiger sneiten mehr ruellen toft don wulka

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  11. 159

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