Bellringer If we applied kineticmolecular theory to liquids

Bellringer If we applied kinetic-molecular theory to liquids and solids, how would you re-word the three basic assumptions of theory?

Liquids and Solids Objectives: 1. State the kinetic theory of matter. 2. Use the kinetic theory to explain states of matter.

The Kinetic-Molecular Theory § Def. (again!): describes the behavior of gases in terms of particles in motion § Can be applied to liquids and solids; however, you must also consider the forces of attraction between the particles. (What kind of forces are these? )

Liquids § Like gases, liquids take the shape of their container. § Unlike gases, the attractive (intermolecular) forces keep the particles closely packed (given liquids a fixed volume).

Behavior of Liquids: § Can liquids and gases of the same substance have the same temperature? 1. Density and Compression: § Density of liquids is much greater than that of gases, AT THE SAME TEMPERATURE AND PRESSURE. § Since KE (and temperature) is the same, what can account for the difference in density? § Liquids CAN be compressed, but not very much. Why not?

Behavior of Liquids: 2. Fluidity: ability to flow § Both gases and liquids are considered fluids. Why? § Can a liquid diffuse? § Which is more fluid, a gas or a liquid? 3. Viscosity: a liquid’s resistance to flow § What do you think would affect (increase) a liquid’s viscosity?

Behavior of Liquids: 4. Surface tension: § Def: the energy required to increase the surface area of a liquid by a given amount § Particles in the middle of a liquid can be attracted to particles to the side, above, and below them. What about the particles at the surface? § The stronger the intermolecular forces, the greater the surface tension.

Water Domes Mini-Lab 1. See how many drops of water you can get on the penny. (Drops must free fall!!!) 2. Dry off the penny and build a 20 -drop water dome on it. 3. If you poke it with a clean, dry pin, does this break the cohesive (attractive) bonds b/t water molecules? 4. Dip the pin in liquid soap and poke the water dome. What happens? 5. How does soap affect surface tension? Propose an explanation for WHY.

Solids § According to kinetic-molecular theory, the kinetic energy of a mole of a solid substance is the SAME as a mole of the same liquid substance AT THE SAME TEMPERATURE. § So why does the solid have a definite shape and volume? Answer: Strong intermolecular forces in the solid limit the motion of the particles to “vibrations around fixed locations”.

Solids, continued…… § How does density of a solid usually compare to that of the same liquid? § Can solids be compressed? § Are solids fluid?