Prime time 9/26/16 Three States of Water Water is an abundant substance on Earth. It can be found as a solid, a liquid, and as a gas called water vapor. 1. How many words can you think of to describe solid water? 2. Where is most of the liquid water on Earth found? Where is most of the water vapor found? 3. Describe a natural event you have observed when water changed from a liquid to a solid, and when water changed from a liquid to a vapor.

Test make ups Come see me before school, during lunch, or after school to make up chapter 2 test so I can pass those back this week If you did not get to finish test and spoke to me come suring one of these times as well

Gas Laws rap winners Based on content and presentation: Period 2 – Group 3 Period 3 – Group 4 Period 7 - Group 2

Gas Laws Homework review game Question 1 Convert the following temperatures to C. a) 67 K b) 1671 K

Question 2 Convert a pressure of 0.0248 mm Hg to the equivalent pressure in pascals (Pa).

Question 3 A sample of nitrogen gas has a volume of 478 cm3 and a pressure of 104.1 kPa. What volume would the gas occupy at 88.2 kPa if the temperature remains constant?

Question 4 8.98 dm3 of hydrogen gas is collected at 38.8 °C. Find the volume the gas will occupy at -39.9 °C if the pressure remains constant.

Question 5

Notes

3.3 Phase Changes Phase Change= the reversible physical change that occurs when a substance changes from one state to another Six common phase changes: Melting Freezing Vaporization Condensation Sublimation deposition

Prime time 9/28/16 1. What is happening at each letter in the diagram? Hint A is solid ice 2. Does condensation occur? Why yes or why not?

Phase changes video Take notes ! https://www.youtube.com/watch?v=EZHmUTmJtF8

Phase Changes Figure 16

3.3 B. Temperature & Phase Changes: 1. Temperature does NOT raise or lower during a phase change… it stays constant 2. Graphs showing phase changes look like stairsteps Energy & Phase Changes During a phase change energy is transferred between substance and surroundings Endothermic=the substance absorbs energy Exothermic= the substance releases energy Heat of Fusion= amount of energy absorbed during melting

Heating Curve for Naphthalene Figure 16

Heating curve of H2O

Heating curve of H2O Condensation Vaporization

Heating curve of H2O Condensation Vaporization Melting Freezing

3.3 Melting & Freezing: 1. Melting a. Arrangement of molecules becomes more orderly during freezing and less orderly during melting b. Energy absorbed during melting helps molecules overcome their “fixed” arrangement c. After melting extra energy increases temp of substance 4. Freezing a. As energy leaves during freezing the molecules move more slowly b. Freezing occurs when molecules arrange in fixed arrangements (does not always need to be cold)

3.3 Vaporization & Condensation: Vaporization=substance changes from a liquid to a gas, is endothermic Heat of vaporization= amount of energy absorbed during vaporization, varies between substances Evaporation= change from a liquid to a gas at a temperature below the boiling point Vapor pressure= pressure created in a closed container when evaporated molecules collide with container walls, increases temp,

3.3 5. Boiling a. liquid is heated until some molecules turn to a gas, these “bubbles” rise to the top of the liquid releasing the vapor b. Boiling occurs when temperature raises vapor pressure to equal atmospheric pressure Condensation= phase change when a gas becomes a liquid Dew on grass, a “sweating” glass Dewpoint= temp at which condensation will happen that day/night

3.3 Sublimation & Deposition: 1. Sublimation= phase change where substance changes from solid to gas without going through liquid state a. Endothermic 2. Deposition=when a substance changes from a gas to a solid without going through the liquid state a. Exothermic b. Frost on windows

Reading Strategy Summarizing a. liquid d. liquid e. gas f. gas Section 3.3 Summarizing a. liquid d. liquid e. gas f. gas b. liquid c. gas

Exit pass 9/28/16 Fill in the endothermic/exothermic charts? What makes something endothermis?

Exit Pass 9/26/16 What is the difference between sublimation and deposition?

Temperature remains constant until the phase change is complete