1 / 30

Properties of Liquids and Solids

Grade 12 STEM General Cheistry

davebugador
Download Presentation

Properties of Liquids and Solids

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Properties of Liquids

  2. How Important Liquids Is? • Liquids are vital to our lives. • Water is a means of food preparation • Cooling machines n industrial processes • Recreation • Cleaning • Transportation

  3. What makes this possible? • Floating needle/paper clip • Water strider floating

  4. CHARACTERISTICS OF LIQUIDS • Surface tension • Capillary action/Capillarity • Viscosity

  5. SURFACE TENSION • A measure of the inward forces that must be overcome in order to expand the surface area of a liquid. • The greater the forces of attraction between molecules of the liquid, the greater the surface tension.

  6. Surface Tension Cont. • Surface tension of a liquid decreases with increasing temperature. • The stronger the intermolecular forces the stronger the surface tension. Water has a high surface tension do to hydrogen bonding.

  7. What makes this possible? • Why do liquids rise through a narrow tube such as the capillary tube?

  8. CAPILLARY ACTION • Another way surface tension manifests. • The rise of liquids up very narrow tubes. This is limited by adhesive and cohesive forces.

  9. Capillarity • The cohesive forces between the like molecules, that s, the IMF within the liquid, compete with adhesive forces of unlike molecules or the forces between the liquid and the walls of the capillary tube. • Capillarity is the ability of liquids to rise in a narrow tube because the adhesive forces are greater than the cohesive forces.

  10. COHESIVE FORCES • Intermolecular forces that bind like molecules to one another (e.g. hydrogen bonding).

  11. ADHESIVE FORCES • Intermolecular forces that bind a substance to a surface.

  12. Formation of meniscus • Water : adhesive forces are greater than cohesive forces • Mercury: Cohesive are greater than adhesive forces.

  13. VISCOSITY • The resistance of a liquid to flow. • The less “tangled” a molecule is expected to be, the less viscous it is. Water = less Viscosity syrup = high Viscosity

  14. Viscosity Cont. • Viscosity decreases with increasing temperature (molecules gain kinetic energy and can more easily overcome forces of attraction). • Viscosity Increases as pressure increases. • Liquids with strong IMF have a higher viscosity.

  15. Structure of Solids • Two ways to categorize solids • Crystalline • Amorphous

  16. Properties of Solids • Solids may be classified according to their structure. Those that have a well-defined shape due to the orderly arrangement of their atoms, molecules or ions are called CRYSTALLINE SOLIDS. • Those which are disorganized are called AMORPHOUS SOLIDS.

  17. Crystalline Solid • Ridged and long range order of its atoms. • Solids have flat surfaces • Sharp/High melting points • EX: Quartz, diamond, sodium Chloride.

  18. Amorphous Solid • Lack a well defined arrangement • No long range order • IMF vary in strength • DO NOT have sharp melting points. EX: rubber, glass

  19. Changes of state • Transformation from one state to another Condensation Vaporization AKA: steam

  20. Changes in state • Liquid  Gas Vaporization Endothermic • Gas  Liquid Condensation Exothermic

  21. Solid  Gas Sublimation Endothermic • Gas  Solid Deposition Exothermic

  22. Solid  Liquid Melting Endothermic • Liquid  Solid Freezing Exothermic

  23. Changes of state • The energy involved it phase changes is calculated using • Heat of fusion (solid  liquid or liquid solid) • Heat of vaporization (liquid gas or gas liquid)

  24. Boiling Point The vapor pressure of the liquid = air pressure above the liquid Note: The normal boiling point of water is 100oC. The term normal refers to standard pressure or 1 atm, or also 101.3 kPa.

  25. Vapor Pressure (vp) Vapor Pressure: Pressure exerted by molecules that have enough energy to escape the surface. As T ↑ VP↑evaporation ↑ Liquids with high VP are volatile (alcohol evaporates easily) Liquids that have strong IMF have low vapor pressures. (take a lot of energy to overcome IMF so it can evaporate)

  26. Boiling Pts. of H2O at Various Elevations

  27. How to make something boil • Increase the VP of the liquid (heat it) so that the VP of the liquid is > that of the atmosphere. • Lower the atmospheric pressure (pressure above the liquid) • At high altitudes (low air pressure) water boils at a lower temperature

  28. Your FAVORITE Part • Next Meeting, We’ll have an activity (SECRET for now), STUDY ON Intermolecular Forces, Properties of Solids and Liquids  FIGHTING!!!

More Related