Dinitrogen tetraoxide, N2O4, and nitrogen dioxide, NO2, exist in dynamic equilibrium with each other - CIE - A-Level Chemistry - Question 2 - 2016 - Paper 1
Question 2
Dinitrogen tetraoxide, N2O4, and nitrogen dioxide, NO2, exist in dynamic equilibrium with each other.
The energy profile for this reaction is shown.
(a) Add labell... show full transcript
Worked Solution & Example Answer:Dinitrogen tetraoxide, N2O4, and nitrogen dioxide, NO2, exist in dynamic equilibrium with each other - CIE - A-Level Chemistry - Question 2 - 2016 - Paper 1
Step 1
Add labelled arrows to the energy profile
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Enthalpy Change, ΔH: Draw an arrow vertically from the line representing N2O4 to the line representing 2NO2. Label this arrow as ΔH.
Activation Energy, E⧧: Draw another arrow vertically from the line representing N2O4 to the peak of the energy profile, where the activation energy is located. Label this arrow as E⧧.
Step 2
Calculate the average molecular mass, M̄
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To calculate the average molecular mass, use the formula:
Mˉ=p×Vm
Substituting the values provided:
Mass, m = 4.606 g
Pressure, p = 1.68 \times 10^2 , Pa
Volume, V = 1.00 , dm^3 = 1.00 \times 10^{-3} , m^3
Thus,
Mˉ=(1.68×102)imes(1.00×10−3)4.606g
Calculating this gives:
Mˉ=73.6gmol−1
Step 3
The number of moles of N2O4 that dissociated can be represented by n
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Amount of N2O4 Remaining: The amount of N2O4 at equilibrium can be expressed as:
0.05 mol−n
Amount of NO2 Generated: The amount of NO2 produced from the dissociation is:
2n
Total Moles at Equilibrium: Therefore, the total moles of NO2 in the equilibrium mixture can be represented as:
moles of NO2=2n
