Pieces of dry ice (solid CO2) totalling 0.6 kg are dropped into a witch\'s cauld
ID: 2185891 • Letter: P
Question
Pieces of dry ice (solid CO2) totalling 0.6 kg are dropped into a witch's cauldron in a school play, to create a "fog" effect. The cauldron is initially filled with 20 kg of water at room temperature (20oC). The dry ice is at the cusp of phase change (at -78oC), and the latent heat of sublimation of dry ice is about 572 kJ/kg. Assume that the resulting carbon dioxide gas bubbles escape out of the cauldron into the environment quickly, but that the environment can otherwise be neglected in this problem. What is the final temperature of the water in the cauldron?Explanation / Answer
totla heat Co2 can give due to sublimision=.6*572*1000=343200 Specific heat water - 4.187 kJ/kgK Specific heat ice - 2.108 kJ/kgK Latent heat of melting - 334 kJ/kg so 343200=20*(20-t)*4187 so t=15.9 degree=16 degree C(ans)