Ammonium nitrate is dangerous because it decomposes (sometimes explosively) when

Question

Ammonium nitrate is dangerous because it decomposes (sometimes explosively) when heated:
NH4NO3(s)N2O(g)+2H2O(g)
Part A
Using the following data, show that this reaction is spontaneous at 25 C.
Gf(N2O) = 104.2 kJ/mol
Gf(H2O) = -228.6 kJ/mol
Gf(NH4NO3) = -184.0 kJ/mol

Essay answers are limited to about 500 words (3800 characters maximum, including spaces).
3800 Character(s) remaining

Part B
How does G for the reaction change when the temperature is raised?

decreases
increases
stays the same

Part C
Calculate the equilibrium constant Kp at 25 C.
Express your answer using two significant figures.

Explanation / Answer

A)

if G <0, then itwill be spontanous

calculate G

G = Gprod - Greact = 104.2 + 2(-228.6) - (-184) = -169 kJ/mol

since G <0, then it is spontnanous

B)

If T increases, then H increases , T increases and S increases

i.e.

G = dH - TdS

assume dH and dS remains constant

if explisve, then dH <0 and dS > 0

for increase of T, this will be highly spontanous

C

Calculate Kp

reclal

Kp = Kc*(RT)^(dn)

dn = gases of (mol of prod - mol of react) = 1+2 - 0 = 3

dG = -RT*lnK

spolve for K

K = dG/(-RT) = exp(169000/(8.318*298)) = 4.0721*10^29

Kp = Kc*(RT)^(dn)

Kp = (4.0721*10^29)(8.314*298)^3 = 6.19294*10^39

Kp = 6.19294*10^39 --> 2 sig fig --> 6.2*10^39

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.