Properties of Liquids

Lecture Note Presentation on the properties of liquids. Designed for HS Chemistry & Earth Systems.

1. Properties of Liquids Properties of Matter Unit Chemistry and Earth Systems 10th Grade Roel Zamora

2. Lesson Objectives & CA Content Standards Students will ask questions and define problems on how the shape and substructure of liquids determine many of its properties and functions. WHST.9-12.2 - Write informative/explanatory texts, including the narration of historical events, scientific procedures/ experiments, or technical processes.

3. Lesson Phenomena (Educational Hook) Thoughts to consider as you watch the video: How does soap affect the properties of milk?

4. Particles in Liquids Particles not fixed in place , they are able to move around each other  Able to flow and take shape of container Denser than gases, particles are closer together Fixed volume (not compressible)  Examples: water at room temperature, mercury, alcohol Kinetic energy of liquid particles is based on the intermolecular attractions of the particles in the liquid 

5. Properties of Liquids Many of the properties of liquids depend on intermolecular forces.    Because liquid particles are in constant contact, liquids are incompressible.  

6. Surface Tension Surface tension: the tendency for a liquid surface to resist penetration • Directly correlated to intermolecular attraction • Surfactant can reduce surface tension

7. Viscosity Viscosity: the thickness or resistance to flow of a liquid • Inversely correlated to temperature • Directly correlated to size (mass) of particles • Directly correlated to strength of intermolecular forces

8. Miscibility Liquids can dissolve solids, other liquids, and gases.  • Dissolve: when a solid, liquid, or gas becomes integrated into a host liquid (solvent)  • Particles become evenly dispersed among liquid particles  • Miscible liquids: dissolve in each other • Immiscible liquids: cannot dissolve in each other  • Particles remain separate

9. What are Intermolecular Forces? the forces which mediate interaction between molecules, including forces of attraction or repulsion which act between atoms and other types of neighboring particles Affects how particles interact with one another (whether they want to be close together, or far apart) Stronger forces    =     more energy to overcome 

10. Kinetic Energy When liquid particles gain enough kinetic energy to overcome their intermolecular attractions, the liquid becomes a gas.    When liquid particles lose energy so that the intermolecular forces become strong enough to hold the particles in fixed positions, the liquid becomes a solid.

11. IMF vs. KE Freezing:   kinetic energy < intermolecular forces  Melting :   kinetic energy > intermolecular forces Condensation:   kinetic energy < intermolecular forces  Boiling :  kinetic energy > intermolecular forces

12. How do intermolecular forces and kinetic energy affect the movement of particles in a liquid? Self Check-in:

13. What happens at a liquid's boiling point?

14. What is Boiling? Boiling is the rapid phase change of a liquid becoming a gas. During boiling, bubbles rise to the surface of liquid because they are less dense than the surrounding liquid.  Boiling happens when the vapor inside of the bubbles of a liquid has high enough kinetic energy to continuously push outward until the bubble reaches the surface of the liquid.  

15. Boiling Point The boiling point is when the vapor pressure is strong enough to overcome the pressure of the surroundings (atmospheric pressure) It is a specific property of a liquid, so different substances have different boiling points. 

16. How do bubbles get their shape? The internal vapor pressure of the gas pushes outwards on the walls of the bubble. If there is not enough energy to maintain the vapor pressure, the bubbles will burst when the surroundings crush them inward!

17. The 1968 Summer Olympics were held at the very high elevation of 2240m in Mexico City. How do you think this affected the athletes and the events?

18. Lesson Phenomena (Educational Hook) Thoughts to consider as you watch the video: How is boiling point changing as they travel upwards in elevation?

19. Does elevation impact boiling? What happens to the boiling point of the water as the team climbs higher? How would this affect the amount of time the hikers would need to cook their food? Self Check-in

20. Culminating Question In your small groups, discuss: What makes matter a liquid? Write down your answer in the form of a CER (claim/evidence/reason) statement