Scan_Doc0139 - AdditionaL Exercises 231 119 The nitrogen...

This preview shows page 1 out of 1 page.

119. The nitrogen content oforganic compounds can be determined bytheDumas method. Thecompound inquestion isfirstreacted bypassage over hot CuO(s): Hot Compound ----c> N 2 (g) + COig) + H 2 0(g) (uo(.<) The product gas isthen passed through aconcentrated solution ofKOH toremove theCO 2 ,After passage through theKOH so- lution, thegas contains N2andissaturated with water vapor. In agiven experiment a0.253-g sample ofacompound produced 31.8 mL N2saturated with water vapor at 25°C and 726 torr. What isthemass percent ofnitrogen inthecompound? (Theva- por pressure ofwater at25°C is23.8 torr.) 120. An organic compound containing only C, H, and N yields the following data. i. Complete combustion of35.0mgofthecompound produced 33.5 mgCO 2 and 41.1 mg H 2 0. ii. A 65.2-mg sample of the compound was analyzed for nitrogen by the Dumas method (see Exercise 119), giving 35.6 mL N2at740. torr and 25°C. iii. The effusion rate ofthe compound as agas was measured andfound tobe24.6mL/min. Theeffusion rateofargon gas, under identical conditions, is26.4 mUmin. What isthe molecular formula ofthecompound? 121. Atmospheric scientists oftenusemixing ratios toexpress thecon- centrations of trace compounds in air. Mixing ratios are often expressed asppmv (parts per million volume): f volofXatSTP 6 ppmv 0 X = X 10 total volofairatSTP
Image of page 1

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern