Be sure to answer all parts. For each reaction, find the value of ΔSo. Report the value with the appropriate sign. (a) 3 NO2(g)
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Answer:
Mass percent of nitrogen in the compound is 13,3%
Explanation:
Dumas method is an analytical method to determine nitrogen content in samples, thus:
CₐHₓNₙ + (2a+x/2) CuO → aCO₂ + ˣ/₂ H₂O + ⁿ/₂ N₂ + (2a+x/2) Cu
As the CO₂ is removed with KOH, in the mixture you have H₂O and N₂
At 25°C. the vapor pressure of water is 23,8 torr, that means that the pressure due to N₂ is:
726torr - 23,8torr = 702,2 torr.
Using gas law:
n = PV/RT
Where:
P is pressure (702,2torr≡ 0,924 atm)
V is volume (0,0318L)
R is gas constant (0,082atmL/molK)
And T is temperature (25°C≡298,15K)
Replacing, number of moles of N₂, n, are:
n = 1,20x10⁻³moles of N₂. In grams:
1,20x10⁻³moles of N₂× =<em> 0,0336 g of N₂</em>.
Thus, mass percent of nitrogen in the compound is:
×100= <em>13,3%</em>
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I hope it helps!