Question

For the decomposition of gaseous dinitrogen pentoxide (shownbelow),
2 N2O5(g).....> 4NO2(g) + O2(g)
the rate constant is k = 2.8 10-3 s-1 at 60°C. The initial concentration of N2O5 is 1.52 mol/L.


(a) What is [N2O5] after 5.00 min?
_____mol/L
(b) What fraction of the N2O5 has decomposed after 5.00 min?
_____

Answer 1

The unit in the problem for k is sec-1 which means this is a first order reaction.
ln(No/N) = kt
No = 1.52 M
N = ?
k = given
t = 5 min
Solve for N.


For part b, You know No and N, fraction remaining is N/No. Subtract from 1.0 to find fraction decomposed.

Post your work if you get stuck.

Answer 2

1.01
0.57

Answer 3

The rate constant for the first order decomposition at 45 o
C of dinitrogen pentaoxide, N2O5, dissolved in
chloroform, CHCl3, is 6.2 x 10-4 min-1
2N2O5 → 4NO2 + O2
What is the rate of decomposition of N2O5 and rates of formation of NO2 and O2 when the concentration of N2O5 is
0.4 mol.dm-3
.