2.201. (a) Vmax=--3bmIM =5.0 1; (b) Pmax= a/27b^2 = 230 atm.
2.202. T„ = 8 / 27 a/bR = 0.30 kK, Pcr = i/3 MTh = 0.34 g/cm^3.
2.203. i1 ----- 8 / 3 MperIpRT, = 0.25, where p is the density of
ether at room temperature.
2.204. Let us apply Eq. (2.4e) to the reversible isothermic cycle
1-2-3-4-5-3-1:
T §dS =§dU-1-§pdV.Since the first two integrals are equal to zero, p dV = 0 as well.
The latter equality is possible only when areas I and II are equal.
Note that this reasoning is inapplicable to the cycle 1-2-3-1, for
example. It is irreversible since it involves the irreversible transi-
tion at point 3 from a single-phase to a diphase state.
2.205. ri =c1tIlq=0.25, where q is the specific heat of melt-
ing of ice; at t = —80°C.
2.206. AT = —(T AV' lq) Ap = —7.5 mK, where q is the spec-
ific heat of melting of ice.
2.207. V;„ qAT/TAp = 1.7 ms/kg, where q is the specific heat
of vaporization, T = 373 K.
2.208. pso Po (1 qMATIRT^2 ) = 1.04 atm where q is the
specific heat of vaporization, pa is the standard atmospheric pressure,
AT = 1.1 K.
2.209. Am/m = (qMIRT — 1) ATIT = 5%.
2.210. p = Po exp [e.(..
i
,!
o_l_)]. These assumptions are admis-
sible in the case of a vapour narrow temperature interval, far below
the critical temperature.
2.211. ii cpTAV'lq 2 = 0.03, where c is the specific heat ca-
pacity of ice, T c:-.1 273 K, q is the specific heat of melting.
2.212. (a) 216 K, 5.1 atm; (b) 0.78, 0.57, and 0.21 kJ/g.
2.213. AS m [c In (T 2 /T^1 ) q/T^2 ] = 7.2 kJ/K.
2.214. As z gm/Ti c In (T^2 /T^1 )^ q^0 /T^2 = 8.6 J/(g•K).
2.215. AS = me In (T/T^1 ) = —10 J/K, where c is the specific
heat capacity of copper, T = 273 K (under these conditions only a
part of the ice will melt).
2.216. (a) When m 2 c 2 t 2 < /nig, not all the ice will melt andAS = m 2 c 2 —1 —ln- 77 4) =9.2 J/K;(b) When rn^2 c^2 t^2 > miq, the ice will melt completely andAS= 2 - Ti + c 2 (m ln-L—m in T^7 ) =18 J/K,
where T = m1ri-f-m2r2—miqlc2^2.217. OS=mq(Tl— Ta) mc —1 — ln -- 0.48 3/K.2.218. C = C p — qMIT = —74 J/(K•mol), where Cp =
= RTley — 1).