Devoir surveillé thermodynamique et chimie I. Atomistique II. Pompe

1s22s22p63s23p63d10 4s24p5
n
dh=cpdT cp>0 T h
hliq hgaz
Lvap =hgaz −hliq

dh=cpdT h
dh= Tds+vdp
dh=vdp v > 0
dh= 0 = Tds+vdpds=−v
Tdp
hB−hA=w+q w
w34 = 0 q34 = 0 ∆h34 = 0
1−2
p1p2> p12−3
3−4
p1
1
∆h= 0 1 −2 ∆h12 =w
2−3 ∆h23 =q23 ∆h34 = 0
4−1 ∆h41 =q41
w+q23 +q41 = 0
2−3
|q23|=−q23

1−2w η =−q23
w
−q23 =w+q41 η= 1 + q41
ww > 0q41 >0η > 1
1bar 10bar
T3= 0◦C
T1= 5◦C
5◦C T4= 0◦C
3
p2= 10bar 40◦C
h(kJ.kg−1)
p3bar 10bar 10bar 3bar
T 5◦C 45◦C 40◦C 0◦C
w= ∆h12 = 22kJ.kg−1q23 = ∆h23 =
−168kJ.kg−1η= 7,6
w+qc+qf= 0
qc
Tc+qf Tf= 0 ηc=−qc wη=Tc Tc−Tf
40◦C
Tc= 313K 5◦C
Tf= 278K ηc= 8,9
Pch =Dm|q23|
Dm=Pch
|q23|≃0,025kg.s−1
pvγ=

wcy =−pdv
∆u=wcomp =
cv(T2−T1)cp−cv=r cv=r
γ−1
pv =rTwcomp =p2v2−p1v1
γ−1
wad−ref =p2v2−p1v1wtot =wcomp +wad−ref =
γ(p2v2−p1v1)
γ−1wcomp
(T, p)p1−γ
1Tγ 1=p1−γ 2Tγ 2
T2= T1p2
p1(γ−1)/γ
T2≃43◦C 45◦C
∆fH0
v= X −Yxi= 1
v= 4
∆rH0=iνi∆fH0
i= 205,7kJ.mol−1
∆rG0= 141,7kJ.mol−1∆rS0=∆rH0−∆rG0
T= 215J.K−1.mol−1
K0=e−∆rG0/RT = 1,45.10−25
∆rH0>0
K0= 16
K0=27α4
4(1 −α2)2
α=1
1 + 27
4K0
= 0,78

p(H2) = 0,66bar p(CO) = 0,22bar p(H2O) = p(CH4) = 0,06bar
Q = n(CO)n(H2)3
n(CH4)n(H2O)n2
tot
p2
p02
n(H2O)
C2H2+5
2O2= H2O + 2CO2
∆rH0=iνi∆fH0
i=−1250kJ.mol−1
Etat initial
T0ξ= 0
Etat final
Tfξf
transformation
r´eelle
Q=0=∆H
T et ξvarient
Etat interm´ediaire fictif
T0ξf
T fix´ee et
ξvarie
T varie et ξfix´ee
•
∆H1→i≈∆H0
1→i=ξf
0
∆rH0(T0)dξ=ξf∆rH0(T0)
•
H2O CO2
N2
Cp=ξf(Cpm(H2O) + 2Cpm(CO2) + 10Cpm(N2)
∆Hi→2≈Cp(Tf−T0)
v= 2 + 3 −(3 + 1) = 1