Unit 6 Notepack States of Matter Name Unit 4 Objectives 1. Describe, at the molecular level, the difference between a gas, liquid, and solid phase. (CH 10) 2. Describe states of matter using the kinetic molecular theory. (CH 10) 3. Describe changes in states of matter with respect to kinetic energy and temperature. (CH 10) 4. Describe the different variables that define a gas. (CH 11) Objective 1: Describe, at the molecular level, the difference between a gas, liquid, and solid phase. Solids shape volume Particles are and packed The particles do not flow. A. Crystalline Solids: Particles are arranged in an pattern. Example: B. Amorphous Solids: Particles are in an orderly fashion. Example: Liquids shape volume Liquids will take the shape of a, but they maintain the same Particles are and packed together. The higher energy allows the particles to around each other. Viscosity: A liquid s to flow. Gases shape volume Gases take the shape of a They also occupy the of the container no matter how big or small it is. High energy motion 1
Plasma energy matter A common example is the Super high energy gas particles that Plasma is the form of matter in the Universe. States of Matter Solids: Liquids: Gases: Particle Spacing: Energy: Motion: Shape: Volume: Particle Spacing: Energy: Motion: Shape: Volume: Particle Spacing: Energy: Motion: Shape: Volume: Objective 2: Describe states of matter using the kinetic molecular theory. Kinetic Molecular Theory Can explain the behavior of in its different Kinetic Molecular Theory: Explains the states of matter based on the concept that the particles in all forms of matter are in Kinetic Energy: Energy an object has due to its Kinetic Energy and Kelvin Temperature Temperature: the kinetic energy of the particles in a material As particles are heated they absorb energy, thus increasing their average and their Motion stops at (0 Kelvin). Kelvin temperature scale reflects the relationship between temperature and average kinetic energy. It is. 2
Objective 3: Describe changes in states of matter with respect to kinetic energy and temperature. Energy and Phase Changes During a, all the energy goes to until phase change is done. The does not change until the phase change is done. Melting: Freezing: Evaporation/Boiling: Condensation: Sublimation: Objective 4: Describe the different variables that define a gas. Gases are mostly 3
The molecules in a gas are separate, very small, and Gas molecules are in constant, chaotic Collisions between gas molecules are (there is no energy gain or loss). The average kinetic energy of gas molecules is directly proportional to the absolute Gas pressure is caused by of molecules with the walls of the container. Behavior of Gases Gases Gases Gases Gases fill their Variables that Describe a Gas Volume: measured in L, ml, cm 3 (1 ml = 1 cm 3 ) Amount: measured in moles (mol), grams (g) Temperature: measured in Kelvin (K) K = ºC + 273 Pressure: measured in mm Hg, torr, atm, etc. P = F / A (force per unit area) Units of Pressure 1 atm = 760 mm Hg 1 atm = 760 torr 1 atm = 1.013 x 10 5 Pa 1 atm = 101.3 kpa Boyle s Law For a given number of molecules of gas at a constant temperature, the volume of the gas varies inversely with the pressure. As P, V and vice versa. Inverse relationship Boyle s Law and Kinetic Molecular Theory How does kinetic molecular theory explain Boyle s Law? Gas molecules are in constant, Gas pressure is the result of molecules with the walls of the container. As the volume of a container becomes smaller, the over a particular area of container wall the gas pressure increases! 4
Pressure Volume Calculations Example: Consider the syringe. Initially, the gas occupies a volume of 8 ml and exerts a pressure of 1 atm. What would the pressure of the gas become if its volume were increased to 10 ml? Equation for Boyle s Law: where: P 1 = initial pressure V 1 = initial volume P 2 = final pressure V 2 = final volume Using the same syringe example, just plug in the values: Example: A sample of gas occupies 12 L under a pressure of 1.2 atm. What would its volume be if the pressure were increased to 3.6 atm? (assume temp is constant) Example: A sample of gas occupies 28 L under a pressure of 200 kpa. If the volume is decreased to 17 L, what be the new pressure? (assume temp is constant) Temperature Volume Relationships What happens to matter when it is heated? o It What happens to matter when it is cooled? o It Gas samples expand and shrink to a much greater extent than either solids or liquids. Charles Law The volume of a given number of molecules is directly proportional to the 5
As T, V and vice versa. Direct relationship V1 T 1 V T 2 2 Temperature Volume Relationship Doubling the Kelvin temperature of a gas its ; Reducing the Kelvin temperature by one half causes the gas volume to by WHY KELVIN? o The Kelvin scale never reaches or has negative values. Converting Kelvin To convert from Celsius to Kelvin: add Example: What is 110 ºC in Kelvin? To convert from Kelvin to Celsius: subtract Example: 555 K in Celsius? Example: A sample of nitrogen gas occupies 117 ml at 100. C. At what temperature would it occupy 234 ml if the pressure does not change? V 1 = T 1 = V 2 = T 2 =??? V 1 / T 1 = V 2 / T 2 Example: A sample of oxygen gas occupies 65 ml at 28.8 C. If the temperature is raised to 72.2 C, what will the new volume of the gas? V 1 = T 1 = V 2 =??? ml; T 2 = V 1 / T 1 = V 2 / T 2 6
Temperature Pressure Relationships Raising the Kelvin temperature of the gas will cause an in the gas pressure. WHY? o With increasing temperature, the K.E. of the gas particles increases they. o They collide more often and with more energy with the walls of the container. 7