4.21 The following data were obtained during the first order thermal decomposition of So,cl, at
a constant volume: SO,CI, (g) - 50,()+C1,(8)
Experiment Time/sec Total pressure/atm
0
0.5
2
100
0.6
Calcu
te the rate of reaction when total pressure is 0.65 atm.
Answers
Answer:
Temperature: 0.01°C; Pressure: 4.6 mmHg
Specific volume of solid: 1.12 cm/8
Specific volume of liquid: 1.00 cm/8
Heat of melting: 80 cal/8
Heat of vaporization: 600 cal/g.
(a) Sketch a p-T diagram for H2O which need not be to scale but
which should be qualitatively correct. Label the various phases and critical
points.
(b) The pressure inside a container enclosing H20 (which is maintained
at T = -1.0°C) is slowly reduced from an initial value of 105 mm Hg. De-
scribe what happens and calculate the pressure at which the phase changes
occur. Assume the vapor phase behaves like an ideal gas.
(c) Calculate the change in specific latent heat with temperature dL/dT
at a point (p, T) along a phase equilibrium line. Express your result in terms
of L and the specific heat Cp, coefficient of expansion a, and specific volume
V of each phase at the original temperature T and pressure p.
(d) If the specific latent heat at 1 atm pressure on the vaporization
curve is 540 cal/8, estimate the change in latent heat 10°C higher than the
curve. Assume the vapor can be treated as an ideal gas with rotational
degrees of freedom.
(MIT)