1. Bell Ringer (on Thursday) Divide into four groups.

2. Solids, Liquids, & Gases The States of Matter Unit 8

3. There are three states (also called phases) of matter. ► The picture to the side represents the same chemical substance, just in different states. http://phet.colorado.edu/ en/simulation/states-of- matter-basics http://phet.colorado.edu/ en/simulation/states-of- matter-basics

4. There are three states (also called phases) of matter. ► Solid: Matter that has both a definite shape and definite volume. ► Molecules or atoms are very close together and can only vibrate a little. They do not move past each other.

5. There are three states (also called phases) of matter. ► Liquid: Matter that has a distinct volume but no specific shape. ► Molecules or atoms are close together but have the ability to slide across one another very easily.

6. There are three states (also called phases) of matter. ► Gas: matter that has no fixed volume or shape. ► It conforms to the volume and shape of its container. Its molecules or atoms are very far apart from each other and move very fast.

8. Density Comparison In most cases: ► Solid is more dense than liquid ► Liquid is more dense than gas ► Gas is the least dense

9. Water is Weird.. Again ► A notable exception is water! The solid state of H 2 O, ice, is less dense than liquid water. This is why ice floats. ► This is true because of the way hydrogen bonds form when liquid water freezes. The hexagonal pattern results in empty space between the molecules.

10. Two Types of Solids Crystalline Solids ► molecules are packed together in a predictable way. ► They are arranged in an orderly, geometric, three dimensional structure. ► The smallest repeating part of a crystalline structure is called a unit cell. Ex: cubic, hexagonal, rhombohedral, etc.

11. Two Types of Solids Amorphous Solids: ► particles are NOT arranged in a regular repeating manner. ► Amorphous means “without shape.” ► Glass, rubber, plastics, wax, etc.

12. Liquids ► Fluidity – liquids (and gases) have the ability to flow.

13. Liquids ► Viscosity – the measure of the resistance of a liquid to flow. ► Cold pancake syrup is very resistant to flow – it is viscous. ► Water flows easily – it is less viscous.

14. GasLiquidSolid low density easy to expand/compress fills container high density hard to expand/compress takes shape of container high density hard to expand/compress rigid shape Three States of Matter - Review

15. Viscosity ► Viscosity decreases with temperature. Ex: heating up the syrup in the microwave makes it pour easier.

16. Transitions between the 3 states of matter:

17. Phase Changes That Require Energy (increase in temperature) ► Melting: solid changing to liquid. Ex: ice melting to liquid water ► Vaporization: liquid to gas, occurs when molecules have enough energy to escape the pull of the other molecules. Ex: heating water on the stove, steam is released. ► Sublimation: solid changing directly into gas. Ex: dry ice (solid CO 2 ) lets off CO 2 gas, looks like steam. Solid air fresheners.

18. Phase Changes that Release Energy (decrease in temperature) ► Condensation: gas to liquid, achieved by removing heat. Ex: “sweat” collects on a cold glass of ice water. ► Freezing: liquid to solid, achieved by removing heat. Ex: water freezing into ice. ► Deposition: gas directly to solid, achieved by removing heat. Ex: frost forms on the grass on a cold morning, snowflakes form from water vapor in clouds.

19. Equilibrium ► is the state in which two opposing processes are equal. ► Equilibrium is the state in which two opposing processes are equal. ► Equilibrium is reached when the rate of condensation equals the rate of evaporation. ► When a liquid is sealed in a closed container, the liquid evaporates, but at the same time the gas condenses back to the liquid state.

20.  HEAT CURVE ► The vertical lines are the phases. ► The horizontal plateaus are the phase changes. ► Notice during a phase change the temperature does not change due to heat of fusion and heat of vaporization.

21. ► Fusion (melting): Heat + Solid  Liquid Freezing: Liquid  Solid + Heat ► Enthalpy or Heat of fusion, ∆H fus, heat required to change a given amount of a substance from a solid to a liquid or released when the substance changes from a liquid to a solid ► Vaporization: Heat + Liquid  Gas Condensation: Gas  Liquid + Heat ► Enthalpy or Heat of vaporization, ∆H vap, heat required to change a given amount of a substance from a liquid to a gas or released when the substance changes from a gas to a liquid

22. Specific Heat Capacity Specific heat is the a mount of heat needed to raise the temperature of 1 g of a substance by 1° C or 1 K. Specific heat is the a mount of heat needed to raise the temperature of 1 g of a substance by 1° C or 1 K. Q = m c ΔT Q = m c ΔT Energy Released/Absorbed = mass x specific heat x temp. change ► Unit for c = J/g°C

23.  HEAT CURVE ► Since Temperature is a measure of "Average Kinetic Energy", any change in temperature is a change in Kinetic Energy. ► Since temperature does not change during a phase change, the energy that is gained or lost is Potential Energy.

24. ► Heat Curve lab you were suppose to do. www.harcourtschool.com/activity/hotplate/index.html

25. PHASE DIAGRAM   HEAT CURVE