General Chemistry II: Lesson 1 - PDF

# GENERAL CHEMISTRY II ## Chapter 1: The Kinetic Molecular Model and Intermolecular Forces of Attraction in Matter ### General Chemistry 2 – Senior High School (STEM) ### Section 1.1: Kinetic Molecular Theory of Solids and Liquids #### EQ: Why do solids and liquids behave differently? ## Kinetic Mo...

# GENERAL CHEMISTRY II ## Chapter 1: The Kinetic Molecular Model and Intermolecular Forces of Attraction in Matter ### General Chemistry 2 – Senior High School (STEM) ### Section 1.1: Kinetic Molecular Theory of Solids and Liquids #### EQ: Why do solids and liquids behave differently? ## Kinetic Molecular Theory - The Kinetic Molecular Theory explains the properties of solids and liquids in terms of intermolecular forces of attraction and the kinetic energy of the individual particles. 1. All matter is made up of tiny particles. 2. These are particles are in constant motion. 3. The speed of particle is proportional to temperature. Increased temperature means greater speed. 4. Solids, liquids, and gases differ in distances between particles, in the freedom of motion of particles, and in the extent to which the particles interact. ## States of Matter - An illustration shows three cylindrical containers with different states of matter. - The first container is labeled "Solid" and contains red spheres arranged in a closely packed structure. - The second container is labeled "Liquid" and contains blue spheres arranged in a less tightly packed structure. - The third container is labeled "Gas" and contains green spheres that are widely dispersed. ## Activity 1 a. Compare the distances among molecules in the gas, liquid and solid and rank the phases in increasing distance between particles. b. Describe the characteristic movement of the particles of gas, liquid and solid. c. How are the molecules of gas, liquid and solid arranged? d. Arrange the three phases of matter in order of increasing volume of empty space between its molecules. ## Properties of Matter | Properties of Matter | gas | liquid | solid | |---|---|---|---| | Volume/Shape | Assumes volume and shape of container | Fixed volume; assumes shape of occupied part of container. | Fixed volume; fixed shape (regardless of size and shape of container | | Density | low | high | high | | Compressibility | Easy to compress | Cannot be appreciably compressed | Cannot be appreciably compressed | | Motion of Molecules | Random, fast, cover large distances | Random, medium speed, limited distances | Vibration in place | ## Kinetic Molecular Theory - Three illustrations show the arrangement of particles. - The first illustration shows particles in a gas state - sparsely packed, moving freely and in all direction. - The second illustration shows particles in a liquid state - closely packed but move freely, and with a more defined shape. - The third illustration shows particles in a solid state - closely arranged and only able to vibrate in places due to strong bonds. ### General Chemistry 2 – Senior High School (STEM) ### Section 1.2: Intermolecular Forces of Attraction #### EQ: How is intermolecular forces defined by nature of particles? ## Intermolecular Forces of Attraction - INTERMOLECULAR FORCES are attractive forces between molecules or particles in the solid or liquid states. - A diagram shows four molecules of ammonia (NH3). The molecules are represented as blue spheres with white spheres for the hydrogen atoms and black spheres for the nitrogen atoms. The hydrogen bonds are shown as dashed lines between the hydrogen atoms and the nitrogen atoms of different molecules. - INTERMOLECULAR FORCES (IMF) are relatively weaker than the forces within the molecules forming bonds (intramolecular forces). - Intramolecular Forces hold atoms together in a molecule. ## Intermolecular Forces of Attraction - The intermolecular forces of attraction in a pure substance are collectively known as van der Waals forces. 1. Dipole-dipole 2. Hydrogen bonding 3. Ion-dipole 4. London dispersion 5. Dipole-induced dipole force ## Dipole-Dipole Forces - Dipole-dipole forces exist between polar molecules. One end of a dipole attracts the oppositely charged end of the other dipole. - A diagram shows three molecules of HCl (hydrogen chloride). The molecules are represented as spheres with a hydrogen atom on one end and a chlorine atom on the other end. The partial positive charges (δ+) are indicated on the hydrogen atoms and the partial negative charges (δ-) are indicated on the chlorine atoms. The dipole-dipole attraction between the molecules is shown as a dashed line between the hydrogen atom of one molecule and the chlorine atom of another molecule. ## Hydrogen Bonding - It is a special and very strong type of dipole-dipole force that exists between a hydrogen atom bound to a small and highly electronegative non-metal atom. - Hydrogen bond occurs in polar molecules containing H and any of highly electronegative elements, in particular Nitrogen, Fluorine, and Oxygen. ## Hydrogen Bonding - A diagram shows a methanol molecule and a water molecule. The methanol molecule is represented as a black sphere (carbon) with four white spheres (hydrogen) attached to it and a red sphere (oxygen) attached to one of the carbon atoms . The water molecule is represented as two white sphere (hydrogen) attached to a red sphere (oxygen). There is a strong hydrogen bond illustrated as a blue dashed line between the oxygen of the methanol molecule and a hydrogen atom of the water molecule. ## Ion-Dipole Force - It acts between an ion (either positive or negative) and a polar molecule. - An illustration shows a spoonful of white powder being poured into a glass of water. - This explains the solubility of ionic compounds in water, which is polar molecule. ## Ion-Dipole Force - The ions and the oppositely charged ends of the polar water molecules overcome the attraction between ions themselves. Each ion becomes separated and water molecules cluster around it. - A diagram shows sodium and chloride ions surrounded by water molecules. The sodium ion is represented as a gray sphere with a + sign. It is surrounded by the negatively charged ends of the water molecules. The chloride ion is represented as a gray sphere with a - sign. It is surrounded by the positively charged ends of the water molecules. ## London Dispersion Forces - It is the weakest type of intermolecular force. - When two non-polar molecules approach each other, an instantaneous dipole moment forms. - This force is sometimes called an induced dipole-induced dipole attraction. ## Dispersion Forces or London Forces - Two oval-shaped molecules are shown. Each molecule illustrates an unequal distribution of electrons which creates a temporary dipole. Dashed lines connect the molecules and show that the attractive force arises from the interaction of the temporary dipoles. ## Dipole-Induced Dipole Forces - Interaction between Polar and non-polar molecules. - An illustration shows a water molecule (H2O) and a Xenon atom. The water molecule is represented by a blue sphere (oxygen) with two white spheres (hydrogen) attached to it, and the Xenon atom is represented by a purple sphere. Dashed lines are shown between the water molecule and the Xenon atoms. This illustrates dipole-induced dipole forces where the polar water molecule induces a dipole in the non-polar Xenon atom. ## Activity 2 What type of intermolecular force will act in the following substances? Justify your answer. 1. sulfur dioxide (SO₂) 2. nitrogen gas (N₂) 3. hydrogen fluoride (HF) 4. carbon dioxide (CO₂) 5. neon gas (Ne) 6. magnesium chloride (MgCl₂) dissolved in water (H₂O) ### General Chemistry 2 – Senior High School (STEM) ### Section 1.3: Intermolecular Forces and Properties of Liquids #### EQ: How do intermolecular forces influence the properties of liquids? ## Intermolecular Forces and Properties of Liquids - Liquids do not have a simple or regular structure, but many of their properties can be explained qualitatively by viewing them at the particulate level. ## Intermolecular Forces and Properties of Liquids - A diagram shows five circles with the following labels: - Surface Tension - Viscosity - Capillary Action - Heat of Vaporization - Boiling Point - The circles are interconnected, creating a star-like pattern, with "General Properties of Liquids" in the center. ## Surface Tension - It is the measure of the elastic force in the surface of a liquid. - It is the amount of energy required to stretch or increase the surface of a liquid by a unit area. - It is manifested as some sort of skin on the surface of a liquid or in a drop of liquid. ## Surface Tension - Surface tension allows needles and paper clips to float in water if placed carefully on the surface. It also explains why drop of water are spherical in shaped - Two illustrations show the surface tension. - The first illustration shows a drop of water on a fabric surface. - The second illustration shows a paperclip floating on the surface of water in a glass bowl. ## Examples - Two illustrations show surface tension in action. - The first illustration shows water striders walking on the surface of a pond. - The second illustration shows a basilisk lizard running on water. ## Examples - Two illustrations show surface tension in action. - The first illustration shows a red apple with water droplets on it. - The second illustration shows a water droplet on a green leaf. - These intermolecular forces tend to pull the molecules into the liquid and cause the surface to tighten like an elastic film or "skin". ## Surface Tension - Molecules within a liquid are pulled in all directions by intermolecular forces. - A diagram shows water molecules in a glass bowl. The molecules are represented as gold spheres connected by brown lines. The brown lines represent attractive forces between the molecules. The water molecules at the surface are pulled in all directions except upward, which creates surface tension. - Molecules at the surface are pulled downward and sideways by other molecules, not upward away from the surface ## Surface Tension - The liquids that have strong Intermolecular forces also have high surface tension. - An illustration shows a bottle of water being poured into a glass. ## Capillary Action - Capillary action is the tendency of a liquid to rise in narrow tubes or be drawn into small openings such as those between grains of a rock . - Capillary action, also known as capillarity, is a result of intermolecular attraction between the liquid and solid materials. ## Capillary Action - Capillary action is shown by water rising spontaneously in capillary tubes. A thin film of water adheres to the wall of the glass tube as water molecules are attracted to atoms making up the glass (SiO2). - A diagram shows five graduated cylinders with water in them. The water levels are higher in the cylinders with smaller diameters. This illustrates the principle of capillary action. ## Capillary Action - Two illustrations show how a plant is able to absorb water through the roots, which is made possible by capillary action. ## Capillary Action - Two types of forces are involved in capillary action: - Cohesion is the intermolecular attraction between like molecules (the liquid molecules). - Adhesion is an attraction between unlike molecules (such as those in water and in the particles that make up the glass tube). - These forces also define the shape of the surface of a liquid in a cylindrical container ( the meniscus!) ## Capillary Action - When the cohesive forces between the liquid molecules are greater than the adhesive forces between the liquid and the walls of the container, the surface of the liquid is convex. - When the cohesive forces between the liquid molecules are lesser than the adhesive forces between the liquid and the walls of the container, the surface of the liquid is concave. ## Capillary Action - An illustration shows the meniscus formation for mercury (Hg) and water (H₂O) in a glass tube. - In the top illustration, mercury is shown as a gray sphere with a curved surface (convex meniscus) in a clear glass tube labeled "Capillary". The gray sphere is labeled as Hg. - In the bottom illustration, water is shown as a blue sphere with a curved surface (concave meniscus) in a clear glass tube labeled "Capillary". The blue sphere is labeled as H₂O. ## Viscosity - It is defined as the resistance of a liquid to flow. - It is loosely referred to as the thickness or thinness of a liquid. - Syrup and oil flow more slowly than water and are thus described as more viscous. - A diagram shows a drop of a liquid falling by a capillary tube. The caption defines viscosity. ## Viscosity - The viscosity of liquid depends on their intermolecular attraction. - The stronger the intermolecular force, the higher is the liquid's viscosity. - A diagram shows a ball falling at different speeds in two liquids, highlighting the principle of viscosity. ## Viscosity - Long-chained substances like oil have greater intermolecular forces because there are more atoms that can attract one another, contributing to the substance's total attractive forces. - An illustration shows a bottle of cooking oil. ## Viscosity - Honey, a concentrated solution of sugar, is also highly viscous because of the hydrogen bonding that forms as a result of the numerous- OH groups of sugar molecule. - An illustration shows a jar of honey with a spoon dipping into it. - A cartoon beneath shows how honey is portrayed in children's books and in real life. ## Vapor Pressure - It is the pressure exerted by its vapor when in equilibrium with liquid or solid. - Example: - When liquid or solid substance is made to evaporate in a closed container, the gas exerts a pressure above the liquid. ## Vapor Pressure - Substances with relatively strong intermolecular forces will have low vapor pressure because the particles will have difficulty escaping as a gas. - Example: 1. Water (H₂O), (Hydrogen Bonding) has vapor pressure of 0.03 atm. 1. Ethyl Ether (C4H10O), dipole-dipole & London Force) has vapor pressure at 0.68 atm. ## Boiling Point - The boiling point of a liquid is the temperature at which its vapor pressure is equal to the external or atmospheric pressure. - Increasing the temperature of a liquid raises the kinetic energy of its molecules, until such point where the energy of the particle movement exceeds the intermolecular forces that hold them together. ## Boiling Point - The liquid molecules then transform to gas and are seen as bubbles that rises to the surface of the liquids and escape to the atmosphere. - Then temperature at which a liquid boils under 1 atmospheric pressure (1atm) is referred to as its normal boiling point. ## Boiling Point - At higher altitude, the atmospheric pressure is lower, hence, the boiling point will subsequently decrease. - The greater intermolecular force, the higher the energy needed to increase the kinetic energy of the molecules to break these forces. ## Boiling Point | Substance | Boiling Point* (°C) | ∆Hvap (kJ/mol) | |---|---|---| | Argon (Ar) | -186 | 6.3 | | Benzene (C6H6) | 80.1 | 31.0|) | Diethyl ether (C2H5OC2H5) | 34.6 | 26.0 | | Ethanol (C2H5OH) | 78.3 | 39.3 | | Mercury (Hg) | 357 | 59.0 | | Methane (CH4) | -164 | 9.2 | | (H₂O) | 100 | 40.79 | ## Heat of Vaporization - Molar Heat of vaporization (▲ Hvap) is the amount of heat required to vaporize one mole of substance at its boiling point. ## Heat of Vaporization - The application of heat disrupts the intermolecular forces of attraction of the liquid molecules and allows them to vaporize. ## Heat of Vaporization - Boiling point generally increases as molar heat of vaporization increases. - The Hvap is also determined by the strength of intermolecular forces between molecules. ## Heat of Vaporization | Substance | Hvap (kJ/mol) | Boiling Point* (OC) | |---|---|---| | Argon (Ar) | 6.3 | -186 | | Pentane (C5H12) | 26.5 | 36.1 | | Acetone (CH3COCH3) | 30.3 | 56.5 | | Ethanol (C2H5OH) | 39.3 | 78.3 | | Water (H2O) | 40.79 | 100 | ## Structure and Properties of Water - An illustration shows water in its three states: solid (ice), liquid (water), and gas (steam). Arrows are shown depicting the transformations between the three states. - At room temperature, pure water is a colorless, odorless and tasteless liquid. - It turns to ice, its solid form at oº C and 1 atm. - At 100° C, it become gas, commonly known as steam. ## Unique Properties of Water 1. Water is a good solvent. 2. Water has a high specific heat. - Specific heat is the amount of heat or energy needed to raise the temperature of one gram of a substance by 1º C. 3. The boiling point of water unusually high. ## Unique Properties of Water 4. Solid water is less dense, and in fact floats on liquid water. - Unlike all other liquids, the molecules in solid water are actually farther apart than they are in liquid water. - When solid water forms, the hydrogen bonds result in a very open structure with unoccupied spaces, causing the solid to occupy a larger volume than the liquid. - This makes ice less dense than liquid water, causing ice to float on water. ## Unique Properties of Water - A diagram shows a hexagonal structure of water molecules that are linked together by hydrogen bonds. ## Unique Properties of Water - An illustration shows a hexagonal structure of water molecules linked by hydrogen bonds. ## Unique Properties of Water - A diagram of the water molecule (H₂O) in its solid state. ### General Chemistry 2 – Senior High School (STEM) ### Section 1.4: Types and Properties of Solids #### EQ: How do you describe solids? ## Types and Properties of Solids - Solid can be classified as crystalline or amorphous based on the arrangement of their particles. - Crystalline solids have highly regular arrangement of particles, while amorphous solids have considerable disorder in their structure. ## Amorphous Solids - Amorphous solids, such a glass, are formed rapidly that its constituent particles do not have time to align or organize into a more crystalline lattice. - An illustration depicts various examples of amorphous solids like glass, biological tissues, dense colloids/ emulsions, foam, grain, fault gouge, sand, silicon panels, and bulk metallic glass. ## Amorphous Solids - Examples of amorphous solids are: - Charcoal - Rubber bands - Glass paper weights - Plastic lunch boxes - An image shows these objects. ## Crystalline Solids - Crystalline Solids have well-defined crystal lattice. - A lattice is a three-dimensional system of points designating the positions of the components (ions, atoms, or molecules) that makeup a crystal. ## Crystalline Solid - An illustration shows a 3D lattice structure of particles in a solid. - An image shows a wooden spoon containing white crystals of table salt (NaCl), a common example of a crystalline solid. ## Crystalline Solids - A unit cell is the smallest repeating unit of lattice. - A diagram shows seven different unit cells: - Cubic - Tetragonal - Orthorhombic - Monoclinic - Hexagonal - Rhombohedral - Triclinic - It shows the edges and angles of the crystal lattice. ## Classification of Crystalline Solids | TYPES | COMPONENTS THAT OCCUPY THE LATTICE POINTS | TYPE OF INTERACTION BETWEEN COMPONENTS OF LATTICE | TYPICAL PROPERTIES | EXAMPLES | |---|---|---|---|---| | IONIC | Ions | Ionic | Hard, high melting point; insulating as solid but conducting when dissolved. | NaCl | | MOLECULAR | Discrete molecules | Dipole-dipole or London dispersion | Soft; low melting point | Ice, dry ice | | METALLIC | Metal atoms | Delocalized covalent | Wide range of hardness and melting points | Silver, Iron, Brass | | NETWORK | Nonmetal atoms | Directional covalent | Hard, high melting point | Diamond | | GROUP 8A | Noble gases | London dispersion forces | Very low melting point | Argon | ## Classification of Crystalline Solids - An illustration showing four common crystal structures as examples of different types of crystalline solids. - The first illustration shows a cubic lattice with alternating red and green spheres. The caption describes it as sodium chloride (NaCl) and labels the green spheres as chloride ions and the red spheres as sodium ions. - The second illustration shows a hexagonal lattice with red spheres and lighter red spheres connected by thin black lines. This represents the crystal structure of ice (H₂O). - The third illustration shows a close packing of spheres with a square structure. The spheres are colored gray. - The fourth illustration shows a hexagonal structure with blue spheres connected by dark blue and lighter blue lines. ### General Chemistry 2 – Senior High School (STEM) ### Section 1.5: Phase Changes and Phase Diagrams #### EQ: When does equilibrium exist between the phases of a substance? ## Phase Changes - Phase Changes are transformations of matter from one physical state to another. - They occur when energy is added or removed from a substance. - They are characterized by changes in molecular order; molecules in the solid phase have the greatest order, while those in the gas phase have the greatest randomness or disorder. ## Phase Changes - What changes in molecular order occur during phase changes? - An illustration shows the particles of the three states of matter (solid, liquid, and gas). - The solid particles are depicted as red circles in a closely packed arrangement, indicating greater order. - The liquid particles are depicted as blue circles in a less tightly packed arrangement, indicating less order. - The gas particles are depicted as single blue circles, indicating greatest disorder. - An arrow points from "Order" on the left side of the illustration to "Disorder" on the right side, indicating that the molecular order decreases moving from solids to gases. ## Types of Phase Changes - An illustration depicts a circular flow diagram showing the different types of phase changes between the three states of matter (solid, liquid, and gas). - The arrow moving from solid to liquid is labeled as "Melting". - The arrow moving from liquid to solid is labeled as "Freezing". - The arrow movoing from liquid to gas is labeled as "Vaporization". - The arrow moving from gas to liquid is labeled as "Condensation". - The arrow moving from solid to gas is labeled as "Sublimation". - The arrow moving from gas to solid is labeled as "Deposition". ## Phase Changes - How does a change in energy affect phase changes? - An illustration shows a graph with temperature on the y-axis and time on the x-axis. The graph depicts the changes in temperature as heat is added to substance over time. The graph has five segments: - The first segment shows the solid phase (blue line) getting hotter. - The second segment shows the phase change from solid to liquid. - The third segment shows the liquid phase getting hotter. - The fourth segment shows the phase change from liquid to gas. - The fifth segment shows the gas getting hotter. ## Phase Changes - An illustration shows the changes in temperature as heat is removed from substance over time. The graph has five segments: - The first segment shows the gas phase (blue line) getting colder. - The second segment shows the condensation of gas to liquid. - The third segment shows the liquid phase getting colder. - The fourth segment shows the freezing of liquid to solid. - The fifth segment shows the solid phase getting colder. ## Phase Diagrams - How can this effect be achieved using CO2 or dry ice? - Two pictures show the effect of dry ice (CO2) in creating a thick smoke-like effect. ## Phase Diagrams - Carbon dioxide cannot exist as a liquid at atmospheric pressure, the dry ice sublimates and instantly produces a gas, condensing water vapor, and creating a thick white fog. ## Phase Diagrams - What does LPG stand for? How can a gas be liquefied? - What conditions are needed to convert a gas into a liquid? - An image of an LPG gas cylinder is shown. ## Phase Diagrams - Liquefied petroleum gas or liquid petroleum gas (LPG or LP gas), are flammable mixtures of hydrocarbon gases. - It is used as fuel in heating appliances, cooking equipment, and vehicles. - An image of an LPG gas cylinder is shown. ## Phase Diagrams - It is a graphical representation of the physical states of a substance under different conditions of temperature and pressure. - It gives the possible combinations of pressure and temperature at which certain physical state or states a substance would be observed. ## Phase Diagrams - An illustration shows a phase diagram with pressure on the y-axis and temperature on the x-axis. The diagram depicts the three states of matter (solid, liquid, and gas) and the transitions between them. - The red line represents the sublimation and deposition curve and divides the solid and gas phases. It touches the triple point (Ttp) and the critical point (Tc). - The blue line represents the vaporization and condensation curve and divides the liquid and gas phases. It touches the triple point (Ttp) and the critical point (Tc). - The green line represents the melting and freezing curve and divides the solid and liquid phases. It touches the triple point (Ttp). - The triple point (Ttp) is the point where all three phases of matter coexist at equilibrium. - The critical point (Tc) is the point where the liquid and gas phases become indistinguishable, forming a supercritical fluid. ## Features of Phase Diagram - Phase diagrams are plots of pressure (usually in atmospheres) versus temperature (usually in degrees Celsius or Kelvin). 1. Three Areas (Solid, Liquid, Gas) ## A. The Three Area - The three areas are marked solid, liquid, and vapor. Under a set of conditions in the diagram, a substance can exist in a solid, liquid, or vapor (gas) phase. ## A. The Three Area - An illustration shows a phase diagram with pressure on the y-axis and temperature on the x-axis. The diagram depicts the three states of matter (solid, liquid, and gas) and the transitions between them. - The diagram shows the three regions/areas: solid, liquid, and gas. The solid phase region is labeled as "A", the liquid phase region is labeled as "B", and the vapor phase region is labeled as "C". ## B. The Three Lines - The lines that serve as boundaries between physical states represent the combinations of pressures and temperatures at which two phases can exist in equilibrium. - In other words, these lines define phase change points. ## Melting (or Freezing Curve) - The green line divides the solid and liquid phases, and represents melting (solid to liquid) and freezing (liquid to solid) points. - An illustration shows the "Melting (or Freezing Curve)” on the Phase Diagram. ## Melting (or freezing) curve - Melting (or freezing) curve – the curve on a phase diagram which represents the transition between liquid and solid states. - It shows the effect of pressure on the melting point of the solid. Anywhere on this line, there is equilibrium between the solid and the liquid. ## Vaporization (Condensation Curve) - The blue line divides the liquid and gas phases, and represents vaporization (liquid to gas) and condensation (gas to liquid) points. - An illustration shows the “Vaporization (Condensation Curve)” on the Phase Diagram. ## Vaporization (Condensation Curve) - The curve on a phase diagram which represents the transition between gaseous and liquid states. It shows the effect of pressure on the boiling point of the liquid. - Anywhere along this line, there will be equilibrium between the liquid and the vapor. ## Sublimation (or deposition) curve - The red line divides the solid and gas phases, and represents sublimation (solid to gas) and deposition (gas to solid) points. - An illustration shows the “Sublimation (or deposition) curve” on the Phase Dlagram. ## Sublimation (or deposition) curve - The curve on a phase diagram which represents the transition between gaseous and solid states. - It represents the effect of increased temperature on a solid at a very low constant pressure, lower than the triple point. ## C. The Two important Points - The triple point is the combination of pressure and temperature at which all three phases of matter are at equilibrium. - It is the point on a phase diagram at which the three states of matter coexist. The lines that represent the conditions of solid-liquid, liquid-vapor, and solid-vapor equilibrium meet at the triple point ## C. The Two important Points - An illustration shows the "Triple Point” on the Phase Diagram. ## C. The Two important Points - The critical point terminates the liquid/gas phase line. It is the set of temperature and pressure on a phase diagram where the liquid and gaseous phases of a substance merge together into a single phase. - Beyond the temperature of the critical point, the merged single phase is known as a supercritical fluid. ## C. The Two important Points - An illustration shows the “Critical Point” on the Phase Diagram. ## Phase Diagram for Water - An illustration shows a phase diagram for water with pressure in atm on the y-axis and temperature in °C on the x-axis. It includes the following features: - Triple Point (A) at 0.0060 atm and 0.01 °C. - Normal Freezing Point (B) at 1.00 atm and 0 °C. - Normal Boiling Point (C) at 1.00 atm and 100 °C. - Critical Point (E) at 217.75 atm and 373.99 °C. ## Phase Diagram for CO2 - An illustration shows a phase diagram for carbon dioxide with pressure in atm on the y-axis and temperature in °C on the x-axis. The illustration depicts the three phases of carbon dioxide: solid, liquid, and gas. ## Activity! Constructing a Phase Diagram Visualize a substance with the following points on the phase diagram: a triple point at 0.05 atm and 150 K; a normal melting point at 175 K; a normal boiling point at 350 K; and a critical point at 2.0 atm and 450 K. The solid liquid line is "normal" (meaning positive sloping). For this, complete the following: 1. Roughly sketch the phase diagram, using units of atmosphere and Kelvin. Label the area 1, 2, and 3, and points T and C on the diagram. 2. Describe what one would see at pressures and temperatures above 2.0 atm and 450 K. 3. Describe the phase changes from 50 K to 250 K at 1.5 atm. 4. What exists in a system that is at 1 atm and 350 K? 5. What exists in a system that is at 1 atm and 175 K?