chem - dry ice activity
posted by janis .
does the dry ice disappear more quickly in air or in water? can you explain why? supplement your explanation with a drawing of molecular behavior based on kinetic molecular theory
What do you think and why? We shall be happy to critique your thoughts.
The dry ice disappears more quickly in water because water transfers heat much more quickly than air does at the same temperature.
but i don't have a clue what the diagram looks like.
You're in the right ball park. Why do you suppose H2O transfers heat better? Could it be becaue the molecules of air are much farther apart in the gaseous state than the moleucules of water in the liquid state. Think about running 5 miles outside on a day when the temperature is 100 F. Would you be sweating? You bet! So you sit down on the curb to cool down. How long will that take? some time, of course. BUT, how much faster would you cool down if someone poured a bucket of cool water on you. Same thing with the CO2 in water vs CO2 in air. I would draw two diagrams, one showing a block of solid CO2 surrounded by gas molecules (with lots of space between the molecules) and the other showing a block of solid CO2 surrounded by water molecules with not much space between molecules. The kinetic theory thing is simply that molecules are in motion and the chance of a water molecule hitting the CO2 and transferring some of the heat away is MUCH better than a molecule of air doing the same thing. I hope this helps.