Carbon dioxide, CO2, changes from the solid phase to the gas phase at 1 atm and 194.5 K. In the solid phase, CO2 is often called dry ice. When dry ice sublimes in air at 298 K, the water vapor in the air can condense, forming a fog of small water droplets. This fog is often used for special effects at concerts and in movie-making.
66 State the direction of heat flow between the dry ice and the water vapor in the air. [1]
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67 At 1 atm and 298 K, compare the potential energies of the water molecules before and after the water vapor condenses. [1]
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| water vapor has a higher PE |
68 At 1 atm and 190. K, compare the amount of thermal energy in a 1.0-kilogram block of dry ice to the amount of thermal energy in a 2.0-kilogram block of dry ice. [1]
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| 2.0kg block has more thermal energy |