Answer Happy

1. (a) As shown below, which is the phase diagram for carbon dioxide, what is the vapor pressure of solid carbon dioxide (dry ice) at -78.5°C? (Note that the axes in the figure are nonlinear and the graph is not to scale.) The letters "s", "I", and "V" on the graph stand for solid, liquid and vapor. CO2 Critical point 73 S 56 Pressure p (atm) V 5.11 Triple point 1 1 1 -78.5 -56.6 20 31 Temperature T (°C) P= atm

(b) Can carbon dioxide be liquefied at room temperature (20°C)? (c) At the temperature of -56.6 °C and pressure of 55 atm, what is the state of carbon dioxide.

1. How much heat transfer (in kilocalories) is required to thaw a 0.3-kg package of frozen vegetables originally at 0°C if their heat of fusion is the same as that of water? Heat of fusion for water is 79.8 kcal/kg. Q= V kcal