Question

The Dumas method can be used to determine the amount of nitrogen in an organic compound. This method involves passing the compound over hot, solid CuO, where it decomposes to give N₂, CO₂ and H₂O (g). The gaseous products are passed through a concentrated KOH solution to remove the CO₂ and then through H₂O. After the passage through H₂O the gas contains only N₂ saturated with water vapor.  When a 0.253-g sample of a certain compound is treated in this way 31.8 mL of N₂ saturated with water vapor is produced at 25.0 °C and a total pressure of 726.1 torr. The vapor pressure of water at 25.0 °C is 23.8 torr.

The pressure of N₂ gas is formed by the decomposition of this compound is ______ torr

In the analysis of a compound by the Dumas method described, the amount of N₂ gas formed in the analysis is _______ mmoles

The compound has a percent N by mass of _______ % according to the Dumas method

From another analysis it is determined that this compound is 79.2% C by mass, and that it contains only C, H, and N. Its empirical formula would, therefore, be C__H__N__

Answer 1

Hot Na (9) + CO₂(g) + H₂O19). compound Curls) during Dumas method we will find & percent of Ne hy mass now 0.2539 of Compand Sample is producing 31 Saml y with water vapon at 25 c d 726. 1 toll ) to tol plestate vapour plesten of 40 = 23.8 toe Ale to part al plesund Ptotal = partial pressure of Ny it paulical pressure of Welel vapool 72611 = Pr + 23.8 toy P 902.3 tot lahm 760 tor) 0.9210 at 70 72. 3 tol tx latm Plestue of negal flomed - 60 fre by decompositions = CR7 Compond to find nog notes of N, gas use ideal gat equation /n- PV where pas 0.924 atom, v = 31.8ml - 31.8 x 12 -0.03181 Temperature gone gas = 25°c = 298k 10ooml = 0.924 atm x 0.0318 10 = 1.20x10 mol 0.0821 x 298 tremmofo & 1.20 mmol amount of a produred (In momoder). produced a 1.20810 mot 28 yond amount of N (in glams) = 0.03368

the pevent of otrogen in the lonpore not 0.03% 69 13.28.1. 9 3.28% of we by mage, % yntogen d o 19.2%, Carbon by and now analysis of anothel Compound has given us rass Simple latio in finding Empire and simula we can nail by mas Carbon 12 792 analyse this method ie. lelative no og atome 79.2 - 6.6 6.6 6.9507 0949 12 7.922 8 7.519 o qua 7.519 = 7.519 7.519 o.qug 13.28 - 0949 0.949 14 hogen in $13.28% a H N the empirical formula is