General Chemistry 2 Quarter 1 Reviewer PDF

GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 LESSON 1: INTERMOLECULAR FORCES PROPERTIES OF MATTER OF LIQUIDS AND SOLIDS Properties Molecular Behavior KINETIC MOLEC...

GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 LESSON 1: INTERMOLECULAR FORCES PROPERTIES OF MATTER OF LIQUIDS AND SOLIDS Properties Molecular Behavior KINETIC MOLECULAR THEORY of matter Gas Liquid Solid 1. All particles are composed of very small Volume/sh Assumes Fixed Fixed particles called atoms or molecules. ape volume volume, volume, 2. The distances between gas particles are and shape assumes fixed of the shape of (regardles so great that the volume of the gas is mostly container occupied s the empty space. part of shape and container size of the 3. There are no repulsive or attractive forces container) between gas particles. 4. These particles are in constant random Density Low High High motion. Compressi Easy to Cannot be Cannot be 5. The kinetic energy of the particles bility compress appreciabl appreciate depends on the temperature of the gas. y compress compress ed ed A Molecule will be Nonpolar if: Motion of Random, Random, Vibration All of the terminal atoms (or groups) molecules fast, cover medium in place are the same. large speed, All of the terminal atoms (or groups) distances limited distance are symmetrically arranged around the central atom. The terminal atoms (or groups) have An increase in temperature results in the same charges. increased kinetic energies of gases A Molecule will be Polar if: dissolving in liquid. One or more terminal atoms differ This increased motion enables the from each other dissolved gas to break At least one polar bond is present intermolecular forces with the The terminal atoms are not solvent, and escape the solution. symmetrically arranged The molecule has one slightly Example: positive end one slightly negative A warm bottle of carbonated drink does not end taste as good as a cold one, because there is less carbon dioxide dissolved in the warm bottle. 1 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 INTRAMOLECULAR FORCES INTERMOLECULAR FORCES Attractive forces that act within Attractive forces that act between molecules or particles in the solid or molecules or particles in the solid or liquid states. liquid states. (much weaker than Are relatively strong because their bonding forces) charges are larger and closer Occur between neighboring together. molecules as a result of partial charges or between ions and TYPES OF INTRAMOLECULAR FORCES molecules. OF ATTRACTION: They are relatively weak because they involve smaller charges that are 1. Ionic bond farther apart. - occurs between metal and nonmetal Intermolecular forces as a whole are compounds. usually called vander Waals forces after the Dutch scientiest Johannes van der Waals (1837-1923). Why melting points and boiling points of substances can be used as indicators of 2. Covalent bond strength of intermolecular forces operating - occurs between two nonmetal in given solids and liquids? compounds. - When a solid melts, or a liquid boils, the particles move away from each other. - As they do, intermolecular forces of attraction are broken. TYPES OF INTERMOLECULAR FORCES 3. Metallic bond - occurs between metal atoms. 1. Ion-Dipole Forces Results when an ion and the partial charge on the end of polar molecule attract each other 2. Dipole-Dipole Forces Attractive forces between polar molecules. In polar molecules the electrons are unevenly distributed because some elements are more electronegative than the others. 2 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 3. Hydrogen bond A special type of dipole-dipole LESSON 2: PROPERTIES OF LIQUIDS interaction between the hydrogen Fluid atom in a polar bond, such as N-H, a gas or a liquid; substance that can O-H, or F-H, and an electronegative flow. O, N, F atom. Hydrogen bonds Surface tension between water molecules are the measure of the elastic force on particularly strong. the surface of a liquid. It is the 4. Dispersion Forces amount of energy required to stretch Forces of attraction result from the or increase the surface of a liquid by temporary dipole moments induced a unit area. in ordinarily nonpolar molecules. Capillary action These forces are present between the tendency of a liquid to rise in ALL types of molecules due to the narrow tubes makes it easily drawn movement of electrons. into small openings. As electrons move around the Viscosity nucleus, the uneven distribution a measure of a fluid’s resistance to causes momentarily charge flow. separations. Vapor Slightly positive sides of the a gaseous substance that exist molecule are attracted to the slightly naturally as a liquid or solid at negative side of the adjacent normal temperature. molecule. Vaporization 5. Polarizability The change of phase from liquid to Refers to the ease with which the vapor (gaseous phase). electron distribution can be distorted. Vapor pressure of a liquid The larger number of electrons, the The equilibrium pressure of a vapor greater its Polarizability. above its liquid; that is, the pressure Thus dispersion forces may be the exerted by the vapor above the weakest of intermolecular forces that surface of the liquid in a closed can exist between two molecules, container. but the larger the atoms present, the Boiling point stronger the dispersion forces. The temperature at which a liquid boils. The boiling point of a liquid when the external pressure is 1 atm is called the normal boiling point. Molar heat of vaporization (ΔHvap) The energy (usually in kilojoules) required to vaporize 1 mole of a liquid at a given temperature. 3 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 Surface tension higher surface tension compared is the measure of the elastic force on to kerosene. the surface of a liquid. It is the amount of energy required to stretch or increase the surface of a liquid by CAPILLARY ACTION a unit area. It is manifested as some sort of skin is the tendency of a liquid to rise in on the surface of a liquid or in a drop narrow tubes or be drawn into small of liquid. openings such as those between Molecules within a liquid are pulled grains of a rock. in all directions by intermolecular Capillary action, also known as forces. capillarity, is a result of Molecules at the surface are pulled intermolecular attraction between downward and sideways by other the liquid and solid materials. molecules, not upward away from the surface. TWO TYPES OF FORCES INVOLVED IN These intermolecular forces tend to CAPILLARY ACTION: pull the molecules into the liquid and 1. Cohesion cause the surface to tighten like an is the the intermolecular attraction elastic film or “skin” between like molecules (the liquid Liquids that have strong molecules) intermolecular forces also have high 2. Adhesion surface tension. 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!) Mercury & Water In A Test Tube ADDITIONAL INFORMATION: Why will water form a spherical droplet on a sheet of plastic, but kerosene will spread? - The water forms a spherical droplet on plastic since it consists of strong intermolecular forces and 4 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 ADDITIONAL INFORMATION: VISCOSITY OF LIQUIDS OF SOME PURE SUBSTANCES Concave Meniscus LIQUIDS VISCOSITY (IN - The molecules of the liquid are NS/M2) AT 20OC strongly attracted to each other. - Cohesion force of the liquid is Acetone (C3H6O) 3.16 x 10-4 great, Benzene (C6H6) 6.25 x 10-4 When the cohesive forces between the liquid molecules are lesser than the Carbon 9.69 x 10-4 adhesive forces between the liquid and tetrachloride (CCl4) the walls of the container, the surface of the liquid is concave. Diethyl ether 2.33 x 10-4 (C2H5OC2H5) Example: water in a glass container Convex Meniscus Ethanol (C2H5OH) 1.20 x 10-3 - The adhesive force is great within the molecules of the container and Glycerol (C3H8O3) 1.49 liquid. Mercury (Hg) 1.55 x 10-3 When both adhesive and cohesive forces are equal, the surface is horizontal. Water (H2O) 1.01 x 10-3 Ex. distilled water in a silver vessel Meniscus - surface shape of a liquid Viscosity - is a measure of a fluid’s resistance Given molecular structures of water and to flow. The greater the viscosity, the glycerol, can you tell why glycerol has a slower the liquid flows. higher viscosity than water? - is expressed in units of centipoise. - The larger number of –OH groups allow glycerol to form more H-bonds Substances with lower viscosities include with other glycerol molecules, carbon tetrachloride and benzene. Glycerol making its intermolecular forces has a resistance to flow of more than a stronger than those of water, and its thousand times greater than water. resistance to flow greater. Consider the table of viscosities that follow. All the substances in the list are hydrocarbons and nonpolar. What causes the differences in viscosities of the Hydrocarbons in the list? 5 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 - The size of the molecules. The Ketchup 50,000 larger the molecule, even if it is Peanut butter 250,000 nonpolar, the stronger the Lava ≈ 4,300,000 intermolecular forces and the greater the viscosity compared to nonpolar - The water molecules in the liquid substances made up of higher evaporate and go into the vapor molecules. phase. In the open flask, some of the water molecules in the vapor phase find their way out of the flask and are lost to the atmosphere. Vapor Pressure of a Liquid What is happening to the water molecules in the two flasks shown in the picture? Liquids that have strong intermolecular forces have higher viscosities than those that have weak intermolecular forces. What effect temperature would have on viscosity? - Viscosity decreases as temperature increases: hot molasses flows much The water molecules in the liquid faster than cold molasses. The evaporate and go into the vapor viscosities of some familiar liquids in phase. In the open flask, some of the table below were measured at the water molecules in the vapor 20 OC, except for lava (ranges phase find their way out of the flask between 700 to 1200°C. and are lost to the atmosphere. When a liquid evaporates to a gas in LIQUIDS VISCOSITY (IN a closed container, the molecules NS/M2) AT 20OC cannot escape. Water 1 Gas molecules move in random Milk 3 directions, collide with other gas Blood 4 to 10 particles and the walls of the Castor oil 1000 container Latex house paint 1500 Some will strike the liquid surface Hotcake syrup 5000 Honey 10,000 and condense back into it. In the Hershey’s 10,000 to 25,000 closed flask, none of the gas chocolate syrup particles are able to get out of the 6 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 container, and eventually, the RELATIONSHIP OF VAPOR PRESSURE number of molecules that go into the TO TEMPERATURE gaseous state would equal the number of molecules that condense back. When the rate of condensation of the gas becomes equal to the rate of evaporation of the liquid, the gas in the container is said to be in equilibrium with the liquid. liquid ⇋ vapor (gas) Vapor Pressure Like any gas sample, the molecules As the temperature increases, the in the gaseous state over its liquid vapor pressure of water also create a pressure. The greater the increases. number of gaseous particles, the When temperature is high, more molecules greater the pressure exerted by the have enough energy to escape from the gas. The pressure exerted by the liquid. At a lower temperature, fewer gas in equilibrium with a liquid in a molecules have sufficient energy to escape closed container at a given from the liquid. temperature is called the equilibrium vapor pressure or RELATION OF VAPOR PRESSURE TO simply vapor pressure of the STRENGTH OF INTERMOLECULAR liquid. FORCES The equilibrium vapor pressure is the maximum vapor pressure of a liquid at a given temperature and that it is constant at a constant temperature. It increases with temperature. Vapor pressure is independent of the amount of liquid as well as the Ethyl alcohol and water have very surface area of the liquid in contact low vapor pressures. Both liquids with the gas. have the strong dipole-dipole interaction called hydrogen bonding. Acetone is polar but does not have H-bonding. Its vapor pressure is of intermediate value. Pentane is a nonpolar substance, and its vapor pressure is high compared to those of water and ethyl alcohol. 7 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 When liquids evaporate, the molecules have to have sufficient Relate Molar Heat of Vaporization To energy to break the attractive forces Strength Of Intermolecular Forces that hold them in the liquid state. The heat of vaporization may be The stronger these intermolecular considered a measure of the forces are, the greater the amount of strength of intermolecular forces in a energy needed to break them. The liquid. If the intermolecular attraction stronger the intermolecular forces of is strong, it takes a lot of energy to attraction, the lower the vapor free the molecules from the liquid pressure of a liquid. phase and the heat of vaporization The stronger the intermolecular will be high. forces of attraction, the lower the It is easier to vaporize acetone vapor pressure of a liquid. (lower Hvap) than water (higher Hvap) at a given temperature, and Molar Heat of Vaporization more acetone escapes into the - The molar heat of vaporization vapor phase at a given temperature. (ΔHvap) is the energy required to Acetone is a polar substance but vaporize 1 mole of a liquid at a given has no H-bonding. It has weaker temperature. H is the symbol for intermolecular forces than water, enthalpy, which means heat content and therefore acetone molecules are at a given standard condition. held less tightly to one another in the liquid phase. SUBSTANCE ΔHVAP BOILING Boiling Point (KJ/ POINT* - The boiling point is the temperature MOL) (OC) at which the vapor pressure of a liquid is equal to the external Argon (Ar)12) 6.3 -186 pressure. - The normal boiling point is the Pentane(C5H 26.5 36.1 temperature at which the liquid Acetone 30.3 56.5 converts to a gas when the external (CH3COCH3) pressure is 1 atm. The normal boiling point of water is 100°C. Ethanol 39.3 78.3 (C2H5OH) Relate boiling point to molar heat of Water (H2O) 40.79 100 vaporization. The relationship between vapor pressure The higher ΔHvap (Molar heat of and strength of intermolecular forces is vaporization) , the higher the boiling consistent with the trends in two other point. properties of liquids, the enthalpy or molar The boiling points of substances heat of vaporization, and the boiling often reflect the strength of the point of the liquid. intermolecular forces operating 8 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 among the molecules. At the BP, (dispersion force, dipole-dipole enough energy must be supplied to attraction, hydrogen bonding). overcome the attractive forces Covalent bond among molecules before they can - A bond in which one or more pairs of enter the vapor phase. electrons are shared by two atoms. Dispersion forces LESSON 3: PROPERTIES OF SOLIDS - Interactions that are the result from temporary dipole moments induced in ordinarily nonpolar molecules. Fluid Dipole-dipole forces - A gas or a liquid; a substance that - Attractive forces between polar can flow. molecules (molecules that possess Crystal or crystalline solid permanent dipole moments). - A solid material whose components, Hydrogen bond such as atoms, molecules or ions, - A special type of dipole-dipole are arranged in a highly ordered interaction between the hydrogen microscopic structure. atom in a polar bond such as N‒H, Ion O‒H, or F‒H, and any of the - An atom or group of atoms that has electronegative atoms O, N, or F. a net positive or negative charge. Crystal lattice Ionic crystal - The regular repeating structure of a - A solid that consists of positively and crystalline solid. negatively charged ions held Unit cell together by electrostatic forces. - The smallest subunit of a crystal Electrostatic bonding lattice that can be repeated over and - The attraction between oppositely over to make the entire crystal. charged ions in a chemical Gemstone compound. - may be a pure chemical element Ionic bond - a relatively simple chemical - The electrostatic force that holds compound (quartz is silicon dioxide, ions together in an ionic compound. SiO2) Network solid or covalent network - a more complex mixture of various crystal compounds and elements - A solid that may be a chemical - The great majority of familiar gem compound (or element) in which materials are oxides or silicates atoms are bonded by covalent (e.g., they contain oxygen and bonds in a continuous network perhaps silicon) extending throughout the material. - formed as crystals during the cooling Molecular crystal of the earth's crust over past - A solid composed of molecules held millennia. together by van der Waals forces - may be formed in single or multiple discrete crystals (such as diamond). 9 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 2. Behaviour when heated In general, larger crystals were formed in a. Crystalline Solids areas of slow cooling for molten rock, and - become liquids at a specific smaller crystals in areas of more rapid temperature (i.e. the melting point). Cooling. - At this temperature, physical properties of the crystalline solids TWO GENERAL TYPES OF SOLIDS change sharply. - Solids can be categorized into two b. Amorphous Solids groups: the crystalline solids and - soften gradually when they are the amorphous solids. heated. They tend to melt over a wide range of temperatures. This FEATURES THAT CAN BE USED TO behavior is a result of the variation in DISTINGUISH A CRYSTALLINE SOLID the arrangement of particles in their FROM AN AMORPHOUS SOLID: structures, causing some parts of the solid to melt ahead of other 1. Arrangement of Particles parts. a. Crystalline Solids - They can form a regular repeating What is the distinguishing feature of three-dimensional structure called a crystalline solids? crystal lattice (the regular repeating - Crystalline solids are characterized structure of a crystalline solid). by a regular repeating structure - are arranged in fixed geometric called the crystal lattice. patterns or lattices. Examples of How are the structures of crystals crystalline solids are ice and sodium determined?: chloride (NaCl), copper sulfate - X-Ray Diffraction is a technique (CuSO4), diamond, graphite, and used to determine the atomic and sugar (C12H22O11). molecular structure of a crystal, - The ordered arrangement of their wherein atoms cause beams of units maximizes the space they incident X-rays to diffract into many occupy and are essentially specific directions. incompressible. b. Amorphous Solids Sugar - They can aggregate with no - Cane stalks are shredded and particular long range order squeezed to extract its natural juice - Amorphous solids have a random and boiled until it thickens and orientation of particles. Examples of molasses – rich sugar crystals begin amorphous solids are glass, plastic, to settle and are sent to a centrifuge coal, and rubber. to remove molasses. - They are considered super-cooled Amethyst liquids where molecules are - formed in silica-rich liquids deposited arranged in a random manner in gas cavities of lava that occur in similar to the liquid state. crystalline masses. 10 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 Uric Acid together. - Byproduct of protein, digestion, and among healthy individuals and is High Melting Strong attractive forces hold Point the atoms in the crystal. removed from the bloodstream and excreted by the kidney. The excess Good electrical Charged particles move conductor through the crystal. uric acid is known as gout Snow Good heat Particles can move through - Formed when temperatures are low conductor the crystal. and there is moisture in the form of Malleable and When the crystal is deformed tiny ice crystals in the atmosphere. ductile or stress is applied, the The tiny ice crystals stick together in attractive forces are not broken. clouds to form snowflakes. Crystallization Lustrous Light is easily absorbed and emitted back. - refers to the formation of solid crystals from a homogeneous solution. It is essentially a solid-liquid PROPERTIES OF METALS/METALLIC separation technique and a very CRYSTALS important one at that. High melting point - large amount of energy is needed to melt crystal 4 TYPES OF CRYSTALS: since the forces of attraction to be 1. Metallic crystals broken are numerous and extend - are made of atoms that readily lose throughout crystal electrons to form positive ions Dense - atoms are packed together (cations), but no atoms in the crystal Electric conductivity - delocalized would readily gain electrons. The electrons move throughout the metal atoms give up their electrons crystal to the whole crystal, creating a Thermal/ heat conductor - structure made up of an orderly decolorized electrons collide with arrangement of cations surrounded each other as they move throughout by delocalized electrons that move the crystal and through these around the crystal. The crystal is collisions that kinetic energy is held together by electrostatic transferred. interactions between the cations and Malleability/ ductility - when stress delocalized electrons. These is applied to metal, metal cations interactions are called metallic shift in position, but the mobile bonds. This model of metallic electrons follow the movement of bonding is called the “sea of cations. Attractive forces between electrons” model. cations and mobile electrons are not broken. OBSERVED INFERENCE ABOUT THE PROPERTY STRUCTURE Luster - motion and collision of electrons allow it to gain and lose Dense Atoms are packed close energy. 11 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 2. Ionic crystals and are unable to move from one - Ionic crystals are made of ions point to another. (cations and anions). These ions - Ionic crystals are brittle, and would form strong electrostatic interactions shatter into small pieces when that hold the crystal lattice together. deformed or when pressure is The electrostatic attractions are applied on the crystal. The shifting of numerous and extend throughout ions causes repulsions between the crystal since each ion is particles of like charges. surrounded by several ions of opposite charge, making ionic 3. Molecular crystals crystals hard and of high melting - Molecular crystals are made of points. atoms, such as in noble gases, or molecules, such as in sugar, OBSERVED INFERENCE ABOUT C12H22O11, iodine, I2, and PROPERTY THE STRUCTURE naphthalene, C10H8. The atoms or molecules are held together by a mix Hard strong attractive forces of hydrogen bonding/dipole-dipole hold the crystal together and dispersion forces, and these are High melting point strong attractive forces the attractive forces that are broken have to be broken melt when the crystal melts. Hence, most the crystal molecular crystals have relatively Poor electrical no charged particles low melting points. conductor in the solid move through the state crystals OBSERVED INFERENCE ABOUT PROPERTY THE STRUCTURE Good electrical mobile charged conductor in molten particles are present in Soft Weak attractive forces state molten state hold the crystal together. Brittle deformation or shift of particles cause Low melting point Weak attractive forces attractive forces to be are broken when broken crystals melt Poor electrical No charged particles - Ionic substances can conduct conductor in the solid move through the electricity in the liquid or molten and molten states crystal state or when dissolved in water, indicating that in these states, Poor heat conductor No particles can move easily throughout the charged particles are able to move crystal. and carry electricity. However, the solid state is generally Brittle Deformation or shift of nonconducting since the ions are in particles cause fixed positions in the crystal lattice 12 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 attractive forces to be Poor heat conductor No particles can move broken. easily throughout the crystal. - The valence electrons of molecular Brittle Deformation or shift of substances are used in bonding, and particles cause attractive forces to be cannot move about the crystal broken. structure. Hence, the crystals are nonconducting. The absence of any mobile particles make molecular - Diamonds are an example of a crystals unable to transmit heat fast. covalent network solid in which The crystals are brittle because the atoms are covalently bonded with attractive forces that hold the each other. They tend to be hard molecules in the crystal are highly and have high melting points. directional and a shift in positions of the molecules would break them. 4. Covalent network crystals - crystals are made of atoms in which each atom is covalently bonded to its nearest neighbors. The atoms can be made of one type of atom (e.g. Cdiamond and Cgraphite) or can be made of different atoms (e.g. SiO2 and BN). In a network solid, there are no individual molecules and the entire crystal may be considered one very large molecule. OBSERVED INFERENCE ABOUT PROPERTY THE STRUCTURE Hard Strong attractive forces hold the crystal together. Very high melting point Strong attractive forces have to be broken in order to melt crystals Poor electrical No charged particles conductor in the solid move through the and molten states crystal 13 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 LESSON 4: INTERMOLECULAR FORCES Triple point OF LIQUIDS & SOLIDS - Combinations of pressure and temperature at which all 3 phases of PHASE DIAGRAM matter area at equilibrium - 3 states of matter coexist - graphical representation of physical - Represents of conditions of states of substance of physical solid-liquid, liquid-vapor, and states of substance under different solid-vapor equilibrium meet at triple conditions of temperature and point pressure Critical point - gives possible combinations of - Terminates liquid/gas phase line pressure and temperature at which - Set of temperature and pressure on physical state a substance would be phase diagram where liquid and observed gaseous phases of substance merge FEATURES OF PHASE DIAGRAM: together into single phase - plots of pressure vs. celsius - Beyond temperature of critical point, - divided into 3: solid, liquid, gaseous merged single phase is - boundary between liquid and supercritical fluid gaseous regions stops at critical temperature for substance PHASE DIAGRAM FOR WATER -boundary between liquid and gaseous regions at point C is critical temperature Freezing (Melting) Curve - Triple point: 0.006 atm and 273. 2 K - Represents the transition between - Critical temperature: 647 K (374°C) liquid and solid states - Critical pressure: 218 atm Vaporization (Condensation) Curve - It is impossible to convert water from - Represents the transition between gas to liquid by compressing it gaseous and liquid states above this temperature Sublimation (Deposition) Curve - Represents the transition between gaseous and solid states 14 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 e. Supersaturated Solutions PHASE DIAGRAM FOR CARBON - contains more solute than is DIOXIDE present in a saturated solution. PERCENT BY MASS AND PERCENT BY VOLUME It is defined as the quotient between the mass of the solute and the volume of solution multiplied by 100%. It is defined as the quotient between the mass of the solute and the volume of solution multiplied by - solid and carbon dioxide is known as 100%. “dry ice” FORMULA: - at 1 atm, CO2 will sublime at 1. Percent by mass = Mass of temperature of 197.5 K (-75.5°C) Solute/Mass of Solution x 100% - there is no liquid CO2 under normal 2. Percent by volume= Volume of conditions – only the solid or the Solute/Volume of Solution x 100% vapor PARTS PER MILLION (ppm) LESSON 5: CONCENTRATION OF SOLUTIONS Is a unit for expressing every dilute concentration. TYPES OF SOLUTIONS: It is commonly used to express the a. Dilute Solutions concentrations of pollutants in air or - contains a small amount of in water. Components of gas solute dissolved compared to mixtures present in very small the solvent. amounts are usually expressed in b. Concentrated Solutions ppm by volume as defined by the - contains a large amount of solute compared to the equation. amount of solvent. FORMULA: c. Saturated Solutions 1. ppm of component = Volume of - contains the maximum Component/Total Volume of amount of a solute that will 6 Solution x 10 ppm dissolve in a given solvent at a specific temperature. d. Unsaturated Solutions MOLARITY - contains less solute than it has the capacity to dissolve. defined as the number of moles of solute per liter of solution. UNIT: mol/L or M 15 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 FORMULA: ethanol (C2H6O), it contains 40 grams of 1. Molarity = Number of Moles of ethanol and 60 grams of water. Solute/Liter of Solution Step 2: Change the masses of the components ethanol and water to the MOLALITY number of moles. is the number of moles of solute dissolved in 1kg of solvent. UNIT: mole/kg or m FORMULA: 1. Molality = Moles of Solute/Kilograms of Solvent Step 3: Substitute the values obtained in the formula and solve for the mole fraction MOLE FRACTION of the solute ethanol, and the solvent water. Is a way of describing solution composition. It is the ratio of the number of moles of one component of a mixture to the total number of moles of all components. Is the ratio of the number of moles of one component (nA) to the total number of moles in the solution (nA + nB). EXAMPLE PROBLEM (for steps in LESSON 6: COLLIGATIVE getting the mole fraction): PROPERTIES OF NONELECTROLYTES What is the mole fraction of the solute in LESSAND ELECTROLYTE SOLUTIONS a 40% by mass ethanol (C2H6O) solution in water? Vocabulary Coligare - Tied together Electrolyte - Is a compound that conducts an electric current when it is an Step 1: In converting concentration units aqueous solution or melted. based on the mass or moles of a solute and Nonelectrolyte solvent or mass percentage, it is useful to - Is a compound that does not assume a certain total mass of solution. conduct an electric current in either Assume there is exactly 100 grams of aqueous solution or in the solution. Because the solution is 40% 16 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 COLLIGATIVE PROPERTY b. Boiling Point Elevation - are properties of a solution that - The addition of a nonvolatile solute depend only on the number and not lowers the vapor pressure of the on the identity of the solute particles. solution; consequently the a. Vapor pressure lowering temperature must be raised to b. Boiling point elevation restore the vapor pressure of the c. Freezing point depression solution to the value conforming to the pure solvent. Specifically, the EFFECT OF SOLUTE CONCENTRATION temperature at which the vapor ON THE COLLIGATIVE PROPERTIES OF pressure is 1 atm will be higher than SOLUTIONS the normal boiling point by an The concentration or amount of amount known as the boiling point nonvolatile solute in the solution has an elevation. effect on the colligative properties of FORMULA: solutions. The effect would depend on the 1. ΔTb = i×Kb×m ratio of the number of particles of solute and Where, solvent in the solution and not on the i is the Van’t Hoff factor, identity of the solute. Kb is the ebullioscopic constant, m is the molality of the solute. EFFECT OF ELECTROLYTE AND NONELECTROLYTE AND NONELECTROLYTE ON COLLIGATIVE PROPERTIES SOLUTIONS a. Vapor Pressure Lowering - Vapor pressure is a direct measure of escaping tendency of molecules. A pure liquid (solvent) in a closed container will establish equilibrium with its vapor. And when that equilibrium is reached, the pressure exerted by the vapor is called the ADDITIONAL INFORMATION: vapor pressure. Van’t Hoff factor - can be defined as the ratio of the concentration of particles formed when a substance is dissolved to the concentration of the substance by mass. 17 GENERAL CHEMISTRY 2 Quarter 1 STEM | LABADIA - TUGA - GUNDAY - BENIGAY | SEM 1 2022 THE LOWERING OF THE VAPOR is equal to the change in the PRESSURE IN A SOLUTION CAUSES freezing-point for a 1 molal solution THE BOILING POINT OF THE SOLUTION of a nonvolatile molecular solute, Tf is the freezing point depression, TO BE HIGHER THAN PURE SOLVENT m is the molality of the solute ADDITIONAL INFORMATION: Which would increase the boiling point of water more: salt or sugar? Why? - More heat energy was needed to break the ionic bond in the salt solution than the covalent bond in the sugar solution so the boiling point of salt solution was higher. c. Freezing Point Depression When a solute is added to a solvent - The freezing point of a substance is forming a solution, what happens to the temperature at which the solid the colligative properties of the liquid? and liquid forms can coexist - Both change in boiling and indefinitely, at equilibrium. Under freezing point may occur if a these conditions molecules pass nonvolatile solute is added to the between the 2 phases at equal rates solvent. When solute is added to a because their escaping tendencies solvent like water, its boiling point from the two phases are identical. increases. However, the effect is - At a given temperature, if a opposite as regards freezing point. substance is added to a solvent like water, the solute-solvent interactions prevent the solvent from going into the solid phase, requiring the temperature to decrease further before the solution will solidify. Meaning, more energy must be removed from the solution in order to freeze it and the freezing point of the solution is power than that of the pure solvent. FORMULA: 1. ΔTf = Kf x m Where, Kf is the molal freezing point depression constant., a constant that 18