States of Matter and the Gas Laws

Matter is anything that has mass and takes up space is classified into one of five states of matter Solid Liquid Gas Plasma BEC

Kinetic Theory of Matter This is used to classify anything into one of the four states of matter. Link to Kinetic Theory of Matter animation

Kinetic Theory of Matter All matter is composed of tiny particles. These particles are in constant motion. The amount of motion is proportional to temperature. Increased temperature means increased particle motion. Solids, liquids, and gases differ in the freedom of motion of their particles and the extent to which their particles interact.

Solids Particles that make up a solid are spaced very close together. The particles have only enough room to vibrate. Solids have a definite shape and a definite volume. Atoms in a solid are packed so tightly that they cannot move around.

Two Types of Solids Amorphous solid Crystalline solid Particles are arranged in repeating geometric patterns called crystals. Amorphous solid Particles are very close together, with no arrangement like glass, wax, plastic.

Liquids According to the Kinetic Theory, particles that make up a liquid have more KE energy (due to higher temperature), thus more motion than a solid. A liquids particles can slide over and around one another. A liquid has no definite shape. However it has a definite volume.

Liquids But why do liquids stay together? Forces of attraction keep the molecules together, such as in water.

Gases According to the Kinetic Theory, gases have the greatest amount of KE, (due to the highest temp) . The particles have freedom to completely separate from one another. They will expand to fill the container they are in.

Gases Gases have no definite shape and no definite volume. Gases will expand to fill the entire room or can be compressed into a small cylinder.

Plasma The fourth state of matter is not made of atoms, like the previous three. A plasma is made of ions and free electrons.

Plasma as a Neon Light Ne atoms Glass is filled with Neon gas (atoms). An electric current is run through the tube, exciting the gas. This releases the electrons and light is given off, forming a plasma. Plug it into the wall

Examples of Plasmas Plasmas are the most common state of matter in the universe (99%) They are found in … Stars Lightning Neon lights Plasma TV

BEC The Fifth State of Matter, the Bose-Einstein Condensate, occurs only at really low temperatures (-273° Celsius - 0°Kelvin) At this temperature, the atoms in a substance begin to move as one.

Pressure Imagine the gas particles inside the balloon. They are constantly exerting forces on the balloon by colliding with each other and the sides of the balloon to keep it inflated. Pressure is the amount of force exerted over an area. Pressure is measured in kPa (kiloPascals)

Pressure Collisions between the particles of gas in a container and the sides of the container cause the particles to bounce around faster, and increase the pressure. The relationship between temperature, number of particles, and the volume of the container affect the pressure of a gas

animation Boyle’s Law According to Boyle’s law, if you decrease the volume of a container of gas, the pressure of the gas will increase, provided the temperature doesn’t change. Increasing the volume will cause the pressure to drop. Boyle’s Law states an inverse relationship between pressure and volume. P1V1 = P2V2

Charles’ Law V1 = V2 ----- ----- T1 T2 States that the volume of a gas increases with increasing temperature (provided the pressure remains constant). As a gas is heated it’s particles move faster and faster and the temperature will increase. V1 = V2 ----- ----- T1 T2

Charles’ Law Charles noticed a straight-line graph during his experiments with gas volume and temperature. He extrapolated the line downward to see the point at which all the heat would be out of the gas, and reached 0°Kelvin. (-273.15° Celsius) No scientist has ever gotten this cold.

Combined Gas Law Using algebra, we can combine Charles’s Law and Boyle’s Law to give us one equation for solving gas problems (not PeptoBismol) P1V1 = P2V2 ---- ---- T1 T2

Practice Gas Problems A cylinder contains air at a pressure of 100kPa and has a volume of 0.75 L. If the pressure increased to 300 kPa, and the temperature does not change, what is the new volume? A gas at a temperature of 20°K has a pressure of 1.5 kPa. If the temperature is raised to 1,000,000°K, and the volume stays the same, what will the new pressure be?

Changes in State This occurs when a substance changes from one state to another. Energy transfer allows substances to change their state. Melting Freezing Boiling Vaporization or Evaporation Condensation Sublimation Deposition

Changes in State During a phase change, the temperature of the substance does not change According to Einstein, matter cannot be created nor destroyed, and neither can energy. Energy is merely transferred during the change, and some is lost as heat.

Melting and Freezing Melting : change in state from a solid to a liquid Freezing : change in state from a liquid to a solid These processes will occur at the same temperature. Water will freeze and melt at 00C.

Vaporization Vaporization : general term for liquid to gas Evaporation: at any temperature, occurs only at the surface of the liquid Boiling: only occurs at one temperature specific to that liquid.

Vaporization

Condensation Condensation occurs when warm, moist air comes in contact with a surface at a lower temperature. Condensation can also occur if gas particles are compressed.

Sublimation Sublimation – is the transition of a solid to a gas without passing through the liquid phase. Dry Ice = - 109 0F Air Temp = 70 0F Temp difference = 179 0F

Deposition The reverse of sublimation, it is the process of going from a gas to a solid while skipping the liquid phase.

Phase Changes Phase changes can either be endothermic (energy is entering the substance) or exothermic (energy is exiting the substance) A substance’s heat of fusion is determined by the amount of energy required to melt one gram of that material The amount of energy required to turn a substance from a liquid to a gas is called the heat of vaporization.

Phase Change Chart Melting Vaporization Sublimation Freezing Condensation Deposition Endothermic Exothermic

States of Matter Chart Solid Liquid Gas Exothermic Endothermic

Phase Change Diagrams This is a line graph plotting temperature (y axis) versus time (x axis). Using the slope of the graph, you can determine the phase of matter at each temperature/time data point plotted. At this time you will be creating a phase change diagram. We will analyze it when you are finished.

Daily Assignment Use the kinetic theory of matter to explain freezing and melting.

Phase Change Diagram

Phase Change Diagram

Daily Assignment Sequence the changes in particle motion that occur when ice is heated until it becomes steam and the steam is cooled until it again becomes ice.

Daily Assignment Humidity is a measure of the percent of water vapor present in the air. Explain the difference in changes in state that occur when you use a dehumidifier versus a humidifier.