Question

The decomposition of dinitrogen pentoxide, N2O5, to NO2 and O2 is a first-order reaction. At 60°C, the rate constant is 2.8 × 10-3min-1. If a rigid vessel initially contains only N2O5 at a pressure of 125 kPa, how long will it take for the total pressure to reach 176 kPa?options (pick 1)a)113 minb)129 minc)42 mind)182 mine)62 minf)83 min

Answer 1

Answer:

The correct option is a.

Explanation:

$2N_2O_5\rightarrow 4NO_2 + O_2$

125 kPa

125kpa - 2x                            4x    x

Total pressure after reaction = 176 kPa

125 kPa - 2x + 4x + x = 176 kPa

x = 17

125 kpa - 2x = 125 kPa - 2(17) = 91 kPa

Initial pressure of the dinitrogen pentoxide ,(at t=0) =$P_o= 125 kPa$

Final pressure of the dinitrogen pentoxide, (at t = t) = P = 91 kPa

The rate constant is = $k = 2.8\times 10^{-3} min^{-1}$

$t=\frac{2.303}{k}\log\frac{P_o}{P}$

$t=\frac{2.303}{2.8\times 10^{-3} min^{-1}}\log\frac{125 kPa}{91 kPa}$

$t=113.3969 minutes\approx 113 minutes$

It will take 113 minutes for the total pressure to reach 176 kPa.