J.R. S. answered 02/28/21
Ph.D. University Professor with 10+ years Tutoring Experience
2NaN3 ==> 2Na + 3N2
Total pressure = 733.8 mm Hg
Vapor pressure of H2O @ 26ºC = 25.2 mm Hg
Vapor pressure due to N2 gas collected over water = 733.8 mm Hg - 25.2 mm Hg = 708.6 mm Hg
Converting this to atm we have 708.6 mm Hg x 1 atm/760 mm Hg = 0.932 atm = P
Converting this to liters of N2, we use the Ideal gas law: PV = nRT
To find moles N2, we use the stoichiometry of the balanced equation:
29.4 g NaN3 x 1 mol / 65 g x 3 mol N2 / 2 mol NaN3 = 0.302 moles N2 = n
R = gas constant = 0.0821 Latm/Kmol
T = temp in K = 26 + 273 = 299K
Solving for V, we have...
V = nRT/P = (0.302)(0.0821)(299) / 0.932
V = 7.95 L

J.R. S.
02/28/21
Dawson H.
It says that answer is wrong, so I don't get it at all.02/28/21