Thermodynamique : changements d`état (PCSI)

m−6C
O C Patm ∆fush= 333kJ.kg−1
ce= 4.18 kJ.kg−1K−1cg= 2.10 kJ.kg−1K−1
(m0eau
−6C
→(m0eau
−0C
→((m0−mg)eau +mgglace
0C∆H=m0(0 −(−6)) ce+
mg(−∆hfus) ∆H= 0 mg
m0=∆T ce ∆hf us = 0.076
∆S=Sc∆S S1+S2dS1=m0cedT
T
S1=m0celn Tf
TiS2=mg(−∆hf us ) TfSc=m0celn Tf Ti−mg∆hf us Tf=m0celn Tf Ti−∆hf us Tf
∆T ce
∆hf us =
m0celn Tf
Ti−Tf−Ti Tf
m1= 120g t1= 0 C
m2= 260g t2= 20 C
m1= 100g t3= 100 C
Lf= 333 J.g−1
Lv= 2250 J.g−1
c= 4.18 J.g−1K−1
m v
v1
v x
v2
v2

15 C Patm 327 C
129J kg−1K−1142 J kg−1K−1
26.3 103J kg−1
125 mL 20 C10g−19 C
Lf= 333 J.g−1
cw= 2.46 kJ.kg−1K−1ce= 4.18 kJ.kg−1K−1
cg= 2.10 kJ.kg−1K−1
Tf
∆H= ∆Hwhiskey + ∆Heau + ∆Hglace =
mwcw(Tf−Twhiskey) + mgcg(O−Tglace) + mg∆fush+mgce(Tf−0 ) = 0
Tf=1
cwmw+cgme(mwcwTwhiskey +mgcgTg+ (−mgcg+mgce) 0 C−mg∆f ush) = 11.9C
∆S
∆S=Srev
ech =mwcwln Tf
Twhiskey +mgcgln 0 Tglace +mg∆f us h O+mgceln Tf 0
Sreel
ech = 0 ∆S=Scree
V mglacon =V ρwhiskey
V0mglacon =V0ρeau
V0< V