1. Phase changes Melting solid  liquid Freezing liquid  solid
Vaporization (or evaporation)
Condensation
Sublimation
Deposition
solid  liquid
liquid  solid
liquid  gas
gas  liquid
solid  gas
gas  solid

2. Heat gain, heat loss Endothermic change – system absorbs heat
Exothermic change – system releases heat

3. Color arrows red if heat is given off, blue if heat is required
Label arrows with vocab words
Solid
Gas
Liquid

4. Heating Curve for Water
120 °C steam (gas)
100 °C water  steam
50°C water (liquid)
0 °C solid liquid
-10 °C ice (solid)
Heat added 

5. Heating curve The flat lines on a heating curve represent
 a change of state
The sloped lines on a heating curve represent
 a temperature change
Key temperatures for water  0 ºC and 100º C

6. Cooling Curve
Using the heating curve of water as a guide, draw a cooling curve for water beginning with steam at 110°C and ending at -20°C.

7. Learning Check 1 A. Water condenses at a temperature of
1) 0°C 2) 50°C 3) 100°C
B. At a temperature of 0°C, water
1) freezes 2) melts 3) changes to a gas
C. When a gas condenses, heat is
1) released 2) absorbed
D. Freezing is
1) endothermic 2) exothermic

8. Solution 1 A. Water condenses at a temperature of 3) 100°C
B. At a temperature of 0°C, water
1) freezes 2) melts
C. When a gas condenses, heat is
1) released
D. Freezing is
2) exothermic

9. Learning Check 2
Is energy absorbed (1) or released (2) in each of the following:
____A. Ice to liquid water
____B. Water vapor to rain
____C. Water to ice
When it rains, the air becomes
1) warmer 2) cooler 3) does not change

10. Solution 2
Is energy absorbed (1) or released (2) in each of the following:
A. Ice to liquid water 1
B. Water vapor to rain 2
C. Water to ice
When it rains, the air becomes
1) warmer

11. Learning Check 3 Complete using the terms gains or loses
In the cooling coils of a refrigerator, liquid Freon ___________ heat from the food and changes to a gas
Food ___________heat and becomes colder
In the back of the refrigerator, Freon _________ heat and condenses back to a liquid

12. Solution 3 Complete using the terms gains or loses
In the cooling coils of a refrigerator, liquid Freon absorbs heat from the food and changes to a gas
Food loses heat and becomes colder
In the back of the refrigerator, Freon loses heat and condenses back to a liquid

13. Combining Heat Calculations
To reduce a fever, an infant is packed in 1250 g of ice. If the ice at 0°C melts and warms to body temperature (37.0°C) how much heat in joules is absorbed?

14. Combining Heat Calculations
Step 1: Diagram the change of state
37°C
T = 37.0°C - 0°C = 37.0°C
0°C S L

15. Step 2: Calculate the heat to melt ice (fusion)
= g ice x 334 J
1 g ice
= 418,000 J
Step 3: Calculate the heat to warm the water from 0°C to 37°C
= g x 37.0°C x J g °C = 193,000 J

16. Total: Step 2 + Step 3
= ,000 J ,000 J
= ,000 J

17. Learning Check 4
A. Why do drops of liquid water form on a glass of iced tea ?
B. When it snows, the air temperature seems warmer. How can that be?
C. How much heat is needed to change 1.00 g of water at 0° to steam at 100°C?
1) 540 cal 2) 640 cal ) 720 cal

18. Solution 4
A. Why do drops of liquid water form on a glass of iced tea?
Condensation of water in the air that cools
B. When it snows, the air temperature seems warmer. How can that be?
Condensation is exothermic; heat is released.
C. How much heat is needed to change 10.0 g of water at 0° to steam at 100°C?
2) 640 cal

19. Last State of Matter Plasma = high energy Found in stars or lightning
Molecules are on top of each other!