1. What question is being answered in this lab? Hint: Look at the Mastery Map in the 2.06 Lesson Introduction.





2. What personal experiences have you had with watching a substance change from one phase to another. Answering this question should help you form your hypothesis.






3. State your hypothesis. (Fill in the blank)
If the ice is melting (or vaporizing), then the temperature will _________________ (increase, decrease, or stay the same).






Step 2: The graph below was created with the data from the video. Analyze this graph and answer the following questions.

The container of ice was placed over a flame.
See the data table for the phase and temperature changes that took place.



Time
(min) Temperature
(°C) State of Matter Observation of the pots contents
(Notes)
0 -16 (solid) Ice
1 0 (solid) Ice beginning to melt
2 0 (some solid and some liquid) Ice and water
3 0 (liquid) Ice all melted into water
4 25 (liquid) Water
5 50 (liquid) Water
6 75 (liquid) Water
7 100 (liquid) Mostly water, steam starts rising
8 100 (liquid and gas) Some water, lots of steam
9 100 (gas) No water, all steam
10 136 (gas) Steam




4. Label the segments of the graph with the following letters:
A. Where only ice was present
B. Where only water was present
C. When only steam was present
D. Where ice was melting
E. When the water was vaporizing



Step 3: Answer the following questions.

5. During which two segments (A, B, C, D, or E) did the temperatures stay the same? What were the temperatures during those two segments?



6. Since the energy was not raising the temperature of the water during those segments, what did the energy do instead? Hint: Think about the connections (bonds) between the molecules.




7. Why did the temperature start to increase again during the 3 to 7 minute segment? Hint: Was the energy still being used to do what you described in #6?




8. What type of process were these phase changes (melting & vaporizing)? (endothermic or exothermic) Why? Hint: Was energy being absorbed or released?







9. Make a general statement about what happens to the temperature of a substance during a phase change.