CHAPTER 10

The Kinetic-Molecular Theory of Matter 10.1

So what makes a solid a solid, a liquid a liquid, and a gas a gas?

 So is that stuff a solid, liquid, or gas?

So what makes a solid a solid, a liquid a liquid, and a gas a gas? The principal difference is the distance between the particles.

So what makes a solid a solid, a liquid a liquid, and a gas a gas? The principal difference is the distance between the particles. Liquids have particles that are very close together with just enough room between so they can slip by one another. Why are these particles so close together?

So what makes a solid a solid, a liquid a liquid, and a gas a gas? The principal difference is the distance between the particles. Liquids have particles that are very close together with just enough room between so they can slip by one another. Intermolecular forces hold the particles of a liquid together.

So what makes a solid a solid, a liquid a liquid, and a gas a gas? The principal difference is the distance between the particles. Liquids have particles that are very close together with just enough room between so they can slip by one another. Intermolecular forces hold the particles of a liquid together. Solids have particles that are even closer together with no room for the particles to slip past one another. Stronger intermolecular forces hold these particles together.

So what makes a solid a solid, a liquid a liquid, and a gas a gas? The principal difference is the distance between the particles. Liquids have particles that are very close together with just enough room between so they can slip by one another. Intermolecular forces hold the particles of a liquid together. Solids have particles that are even closer together with no room for the particles to slip past one another. Stronger intermolecular forces (and sometimes intramolecular forces) hold these particles together. Gases have particles that are very far apart. Very weak intermolecular forces exist between the particles.

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion.

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion. This theory helps explain the physical properties of solids, liquids, and most importantly gases.

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion. This theory helps explain the physical properties of solids, liquids, and most importantly gases. What is an ideal gas?

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion. This theory helps explain the physical properties of solids, liquids, and most importantly gases. An ideal gas is a gas which follows the definition of the KMT. This gas does not truly exist, but noble gases and some nonpolar diatomic gases come close. (Ex – He, Ne, Ar, H 2, O 2, N 2 )

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion. This theory helps explain the physical properties of solids, liquids, and most importantly gases. An ideal gas is a gas which follows the definition of the KMT. This gas does not truly exist, but noble gases and some nonpolar diatomic gases come close. (Ex – He, Ne, Ar, H 2, O 2, N 2 ) Why would these gases be close to an ideal gas?

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion. This theory helps explain the physical properties of solids, liquids, and most importantly gases. An ideal gas is a gas which follows the definition of the KMT. This gas does not truly exist, but noble gases and some nonpolar diatomic gases come close. (Ex – He, Ne, Ar, H 2, O 2, N 2 ) These gases have very weak intermolecular forces (London dispersion or induced dipole) between the atoms or molecules.

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion. This theory helps explain the physical properties of solids, liquids, and most importantly gases. An ideal gas is a gas which follows the definition of the KMT. This gas does not truly exist, but noble gases and some nonpolar diatomic gases come close. (Ex – He, Ne, Ar, H 2, O 2, N 2 ) How does a real gas differ from an ideal gas?

10.1 NOTES The kinetic molecular theory (KMT) is based on the idea that particles in matter are in constant motion. This theory helps explain the physical properties of solids, liquids, and most importantly gases. An ideal gas is a gas which follows the definition of the KMT. This gas does not truly exist, but noble gases and some nonpolar diatomic gases come close. (Ex – He, Ne, Ar, H 2, O 2, N 2 ) A real gas has intermolecular forces which act between the particles, an ideal gas does not have any intermolecular forces.

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart.

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. This explains the low density of gases and how easily compressible they are.

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. 2. Gas particles are in constant motion and travel in straight lines until they hit the sides of the container or each other. Collisions among particles are perfectly elastic. What is meant by an elastic collision?

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. 2. Gas particles are in constant motion and travel in straight lines until they hit the sides of the container or each other. Collisions among particles are perfectly elastic. In an elastic collision, there is no loss of total kinetic energy. (A particle may transfer its energy to another particle or to the side of the container, but it is not lost to the system.) P. 330

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. 2. Gas particles are in constant motion and travel in straight lines until they hit the sides of the container or each other. Collisions among particles are perfectly elastic. In an elastic collision, there is no loss of total kinetic energy. (A particle may transfer its energy to another particle or to the side of the container, but it is not lost to the system.) This explains how gases exert pressure on the sides of the container and how they will their container. It also explains how gases mix. P. 331 Diffusion – gases moving through each other Effusion – gases moving through a membrane Gases with a high molar mass diffuse and effuse slower.

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. 2. Gas particles are in constant motion and travel in straight lines until they hit the sides of the container or each other. Collisions among particles are perfectly elastic. In an elastic collision, there is no loss of total kinetic energy. (A particle may transfer its energy to another particle or to the side of the container, but it is not lost to the system.) 3. Gas particles have no attraction to one another.

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. 2. Gas particles are in constant motion and travel in straight lines until they hit the sides of the container or each other. Collisions among particles are perfectly elastic. In an elastic collision, there is no loss of total kinetic energy. (A particle may transfer its energy to another particle or to the side of the container, but it is not lost to the system.) 3. Gas particles have no attraction to one another. Gases can be poured easily.

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. 2. Gas particles are in constant motion and travel in straight lines until they hit the sides of the container or each other. Collisions among particles are perfectly elastic. In an elastic collision, there is no loss of total kinetic energy. (A particle may transfer its energy to another particle or to the side of the container, but it is not lost to the system.) 3. Gas particles have no attraction to one another. 4. The temperature of a gas depends on the average kinetic energy of the particles in a gas. KE = ½ mv 2

10.1 NOTES KMT of gases: 1. Gas particles are extremely small, have a small mass and are spread far apart. 2. Gas particles are in constant motion and travel in straight lines until they hit the sides of the container or each other. Collisions among particles are perfectly elastic. In an elastic collision, there is no loss of total kinetic energy. (A particle may transfer its energy to another particle or to the side of the container, but it is not lost to the system.) 3. Gas particles have no attraction to one another. 4. The temperature of a gas depends on the average kinetic energy of the particles in a gas. KE = ½ mv 2 Any gas at the same temperature as another gas must have the same average kinetic energy. Smaller mass must have a higher velocity and visa versa.

10.1 NOTES Properties of gases  Particles have mass and volume  Particles are spread far apart  Particles are not attracted to one another  Particles are in constant motion

Liquids and Solids 10.2 and 10.3

10.2 and 10.3 NOTES Gases and solids are very common, but liquids are less common. Why?

10.2 and 10.3 NOTES Liquids only exist in a very defined pressure and temperature range. Water is a true anomaly because it is primarily found as a liquid on this planet where as other compounds with about the same molar mass are gases. (Ex – NH 3, CO 2, CH 4 etc.) Why is this the case?

10.2 and 10.3 NOTES Liquids only exist in a very defined pressure and temperature range. Water is a true anomaly because it is primarily found as a liquid on this planet where as other compounds with about the same molar mass are gases. (Ex – NH 3, CO 2, CH 4 etc.) The strong hydrogen bonds, the temperature and pressure all allow H 2 O to be in the liquid state.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container. Explains liquids exerting pressure on the sides of the container.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container. 2. Particles are very close together, but can move past one another.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container. 2. Particles are very close together, but can move past one another. Explains how liquids can flow and why they can be only slightly compressed. Also explains how their densities are much higher than gases. Also explains how liquids can diffuse through other fluids.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container. 2. Particles are very close together, but can move past one another. 3. Particles are pulled toward each other and can be attracted to solid objects.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container. 2. Particles are very close together, but can move past one another. 3. Particles are attracted toward each other and can be attracted to solid objects. This explains surface tension and capillary action.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container. 2. Particles are very close together, but can move past one another. 3. Particles are attracted toward each other and can be attracted to solid objects. 4. Particles containing enough kinetic energy will “escape” the surface of the liquid and change state to a gas. The opposite also occurs, gas particles which lose energy will rejoin the liquid.

10.2 and 10.3 NOTES KMT as it applies to liquids. 1. Particles are in constant motion, collide with each other and the sides of the container. 2. Particles are very close together, but can move past one another. 3. Particles are pulled toward each other and can be attracted to solid objects. 4. Particles containing enough kinetic energy will “escape” the surface of the liquid and change state to a gas. The opposite also occurs, gas particles which lose energy will rejoin the liquid. This explains how in a closed container, liquids exert vapor pressure above the liquid’s surface. P. 336

10.2 and 10.3 NOTES KMT as it applies to solids. 1. Solid particles are also in constant motion, but can be locked into position, so the motion is more of a vibration. P. 337

10.2 and 10.3 NOTES KMT as it applies to solids. 1. Solid particles are also in constant motion, but can be locked into position, so the motion is more of a vibration. Crystalline solids have very ordered arrangements. P. 339 Amorphous solids have less ordered arrangements. (Ex. - glass, plastic)

10.2 and 10.3 NOTES KMT as it applies to solids. 1. Solid particles are also in constant motion, but can be locked into position, so the motion is more of a vibration. 2. Solid particles are very close together.

10.2 and 10.3 NOTES KMT as it applies to solids. 1. Solid particles are also in constant motion, but can be locked into position, so the motion is more of a vibration. 2. Solid particles are very close together. Solids can’t be compressed and have a very high density.

10.2 and 10.3 NOTES KMT as it applies to solids. 1. Solid particles are also in constant motion, but can be locked into position, so the motion is more of a vibration. 2. Solid particles are very close together. 3. When solid particles gain enough kinetic energy to overcome the intermolecular forces, and are no longer locked into position, they move far enough apart to slip past one another.

10.2 and 10.3 NOTES KMT as it applies to solids. 1. Solid particles are also in constant motion, but can be locked into position, so the motion is more of a vibration. 2. Solid particles are very close together. 3. When solid particles gain enough kinetic energy to overcome the intermolecular forces, and are no longer locked into position, they move far enough apart to slip past one another. = melting or subliming

10.2 and 10.3 NOTES KMT as it applies to solids. 1. Solid particles are also in constant motion, but can be locked into position, so the motion is more of a vibration. 2. Solid particles are very close together. 3. When solid particles gain enough kinetic energy to overcome the intermolecular forces, and are no longer locked into position, they move far enough apart to slip past one another. 4. Solid particles exhibit very little diffusion.

10.2 and 10.3 NOTES COVALENT NETWORK SOLID COVALENT MOLECULAR SOLID METALLIC SOLID IONIC SOLID

10.2 and 10.3 NOTES What is an allotrope? What do diamonds, pencil “lead”, and charcoal all have in common?

10.2 and 10.3 NOTES

FULLERENE 540 FULLERENE C 70 AMORPHOUS NANOTUBE CARBON DIAMOND GRAPHITE LUNSDALEITE FULLERENE C 6O

10.2 and 10.3 NOTES So what is a nanotube?

10.2 and 10.3 NOTES Diamond – jewelry, cutting tips for saws Graphite – pencils, conductors Lunsdaleite – hardest substance naturally made Fullerenes and nanotubes –  High tensile strength (100 times stronger than steel)  High ducility  High electrical and heat conductivity  Chemical inactivity Uses – medicine delivery to specific bacteria or cancer cells, semi- conductors for electronics (conductive paper), televisions, flexible displays, body armor, bone regrowth, solar cells,

10.2 and 10.3 NOTES How about this?

10.2 and 10.3 NOTES How about this? This is called aerogel. It is a synthetic ultralight material where the liquid in a gel has been replaced by gas. It is considered a solid with extremely low density and low thermal conductivity.

10.2 and 10.3 NOTES The gel can be made from silicon, aluminum, or carbon. Some uses are in tennis rackets, insulation, chemical absorber for oil spills, and by NASA to trap space particles.