Sean Munroe2-4-15Period 5Phase Change Lab Write-Up

1. The phase of water at -5 degrees Celsius is ice(solid). In this phase the molecules do not move from place to place, they vibrate.

2. Refer to the graph for 2a and 2b. While leveling out, the water is changing its phase. In this case from Ice to both to water. As water turns from ice to water the molecules attraction to each other becomes weaker, but they are still strong enough to be together. The molecules move freely instead of just vibrating. When changing phase the heat added is used as energy to change the phase of ice to water in this case.

3. In this case, the heat of fusion is the heat energy needed to change one kilogram of water in its solid state to one kg of water in its liquid state. The heat of vaporization would be the heat energy needed to change one kilogram of water in its liquid state to one kg of water in its gaseous state. The heat of fusion for water is 3.35x10^5 joules/kilograms. The heat of vaporization for water is 2.26x10^6 joules/kilograms. The main reason that it takes more energy to convert water to a gas than it takes to convert ice to water is because of the much higher specific heat capacity of water compared to ice.

4. Well start with water in its solid state(ice). The molecules do not move around, they vibrate. It is interesting that molecules expand when frozen. As the temperature rises, water goes under a phase change to water. Water molecules are still attracted to each other, but these molecules move around freely. As the temperature rises more and more, the water turns into its gaseous state. In its gaseous state, there is no attraction between the molecules and the molecules move around randomly in random directions. In our lab, my group observed the phase change from ice to a slushy mixture to water. The ice turned to a slushy mixture at 1 degrees celsius after only 5 minutes. Then the slushy mixture turned to completely water at 7.5 degrees celsius after 30 minutes. During the phase changes there were long flat stretches on our graph that represent the respective phase changes. Heat energy is added to the system during the phase change, but the temperature doesnt change because the energy is being used to convert the ice to the slushy mixture to the water.