Chemistry 5 th 6 Weeks

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1 NAME OF UNIT UNIT V ESTIMATED # OF DAYS 5 th 6 Weeks Weeks 1-2 Weeks 3-4 Weeks 5-6 Components Unit Name VA: Limiting Reagents VB: Thermochemistry and States of Matter Short Descriptive Overview TEKS Stoichiometry is used to develop the concepts of limiting reagents and percent yield. Scientific Process Skills C.1.A demonstrate safe practices during laboratory and field investigations, including the appropriate use of safety showers, eyewash fountains, safety goggles, and fire extinguishers C.1.B know specific hazards of chemical substances such as flammability, corrosiveness, and radioactivity as summarized on the Material Safety Data Sheets (MSDS) C.1.C demonstrate an understanding of the use and conservation of resources and the proper disposal or recycling of materials C.2.A know the definition of science and understand that it has limitations, as specified in chapter , subsection (b)(2) of 19 TAC C.2.B know that scientific hypotheses are tentative and testable statements that must be capable of being supported or not supported by observational evidence. Hypotheses of durable explanatory power which have been tested This unit describes exothermic and endothermic reactions. Students will learn to differentiate between heat capacity and specific heat. Heat changes also occur during changes of state. This unit describes heats of fusion and solidification and heats of vaporization and condensation. It also discusses collision theory and it s relation to activation energy required for the reaction to take place. Factors that affect reaction rate will be introduced as well as discussion of entropy and enthalpy. (4) Science concepts. The student knows the characteristics of matter and can analyze the relationships between chemical and physical changes and properties. The student is expected to: (C) compare solids, liquids, and gases in terms of compressibility, structure, shape, and volume; Supporting (11) Science concepts. The student understands the energy changes that occur in chemical reactions. The student is expected to: (A) understand energy and its forms, including kinetic, potential, chemical, and thermal energies; Supporting (B) understand the law of conservation of energy and the processes of heat transfer; VC: Gas Laws This unit examines effects of changes in the pressure, volume, and temperature of contained gases. Using the kinetic theory, students can often explain how gases will respond to a change of conditions without resorting to formal mathematical expressions (9) Science concepts. The student understands the principles of ideal gas behavior, kinetic molecular theory, and the conditions that influence the behavior of gases. The student is expected to: (A) describe and calculate the relations between volume, pressure, number of moles, and temperature for an ideal gas as described by Boyle's law, Charles' law, Avogadro's law, Dalton's law of partial pressure, and the ideal gas law; Readiness (B) perform stoichiometric calculations, including determination of mass and volume relationships between reactants and products for reactions involving gases; Supporting (C) describe the postulates of kinetic 1

2 over a wide variety of conditions are incorporated into theories C.2.C know that scientific theories are based on natural and physical phenomena and are capable of being tested by multiple independent researchers. Unlike hypotheses, scientific theories are well established and highly reliable explanations, but may be subject to change as new areas of science and new technologies are developed; C.2.D distinguish between scientific hypotheses and scientific theories C.2.E plan and implement investigative procedures, including asking questions, formulating testable hypotheses, and selecting equipment and technology, including graphing calculators, computers and probes, sufficient scientific glassware such as beakers, Erlenmeyer flasks, pipettes, graduated cylinders, volumetric flasks, safety goggles, and burettes, electronic balances, and an adequate supply of consumable chemicals C.2.F collect data and make measurements with accuracy and precision C.2.G express and manipulate chemical quantities using scientific conventions and mathematical procedures, including dimensional analysis, scientific notation, and significant figures C.2.H organize, analyze, evaluate, make inferences, and predict trends from data C.2.I communicate valid conclusions supported by the data through methods such as lab reports, labeled drawings, graphs, journals, summaries, oral reports, and technology based reports C.3.A in all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence, logical reasoning, and experimental and observational testing, including examining all sides of scientific evidence of those scientific explanations, so as to encourage critical thinking by the student C.3.B communicate and apply scientific information Supporting (C) use thermochemical equations to calculate energy changes that occur in chemical reactions and classify reactions as exothermic or endothermic; Readiness (D) perform calculations involving heat, mass, temperature change, and specific heat; Supporting (E) use calorimetry to calculate the heat of a chemical process. Supporting molecular theory. Supporting 2

3 Generalizations/Enduring Understandings extracted from various sources such as current events, news reports, published journal articles, and marketing materials C.3.C draw inferences based on data related to promotional materials for products and services C.3.D evaluate the impact of research on scientific thought, society, and the environment C.3.E describe the connection between chemistry and future careers C.3.F research and describe the history of chemistry and contributions of scientists (8) Science concepts. The student can quantify the changes that occur during chemical reactions. The student is expected to: (E) perform stoichiometric calculations, including determination of mass relationships between reactants and products, calculation of limiting reagents, and percent yield. Supporting 1) The amount of products that can be formed in reactions is limited by the amounts of reactants. 2) Results in the lab often times differ from calculated results, and a measure (or percentage) of that difference can be important. 1) A phase diagram can be used to show all the phases of a substance as the pressure and temperature are changed. 2) Energy cannot be created or destroyed in a reaction. 3) Energy flow during exothermic and endothermic processes can be quantified. 4) The rate at which a chemical reaction proceeds is determined by the number of collisions between reacting particles and the energy with which the particles collide. 5) The natural tendency for all the things to go to lower heat content (enthalpy) and greater randomness (entropy) determines whether a reaction will occur (is spontaneous). 1) Kinetic molecular theory can be used to explain the behavior of gases. For example, how gases react when variable such as temperature, pressure, volume, and amount are manipulated. 2) Gases diffuse from areas of high concentration to areas of low concentration. The rate at which molecules diffuse depends on the size and molar mass of the molecule. 3

4 Guiding/Essential Questions 1) What do you do if a problem has two givens? 2) How does a limiting reagent affect a chemical reaction? 3) What is a limiting reagent? An excess reagent? 4) What is the difference between the actual and theoretical yield? 5) Where do you see examples of processes or activities being limited on a daily basis? 6) Why are limiting reagents important? 7) What is the percent yield of a reaction? 1) What makes a liquid different from a solid? 2) What happens to the vapor pressure of a liquid as the temperature increases? 3) What is the normal boiling point of water? 4) What is meant by the term vapor pressure? 5) How many different molecular forms of carbon are there, and what are these forms called? 6) How are the solid, liquid, and vapor states related? 7) Why does lava cool more quickly in water than on land? 8) Is there a way to measure exactly how much heat is released from a burning match? 9) A match won t ignite unless you strike it and add the heat produced from friction, Is the burning of a match an endothermic reaction? 10) Why does the evaporation of sweat from your skin help to rid your body of excess heat? 11) Is evaporation endothermic or exothermic? 12) At what temperature does water freeze? At what temperature does water melt? 13) Is there a way to determine the heat of reaction without actually performing the reaction? 1) How do the gaseous odor molecules travel from one place to another? 2) What units are normally used to express the pressure of a gas? 3) What happens when a substance is heated? 4) What is standard temperature? 5) What is standard pressure? 6) How does kinetic theory explain why losing helium causes the balloon to sag and collapse? 7) What assumption does kinetic theory make regarding gas particles? 8) What assumption explains why gas expands? 9) What does kinetic theory say about the collisions between gas particles? 10) What factors affect the gas pressure inside a raft and its resulting rigidity? 11) How does increasing the number of gas particles affect the pressure? 12) Why does the pressure of a contained gas double when the volume is reduced by one-half? 13) What is the effect of adding heat to a gas at constant pressure? What law describes this relationship? 14) What is an ideal gas, and under what conditions do the gas laws apply? 15) What is meant by the term partial pressure, and why does it describe as altitude increases? 4

5 Learning Targets Performance Levels Learning Progressions 1) Students will 1) Students will calculate the interpret balanced amount of chemical equations substance in terms of consumed and interacting moles, produced in a representative chemical particles, masses, reaction. and gas volume at Prerequisite STP. knowledge: 2) Students will Students will construct mole understand the ratios from relative balanced equations amounts of and apply these reactants and ratios in mole-mole products in a stoichiometric balanced calculations. equation. 3) Students will Students recall calculate chemical stoichiometric conversions quantities from using the Mole balanced chemical unit. equations using units of moles, mass, 14) What is meant by the rate of a chemical reaction? 15) What factors affect the rate of a chemical reaction? 16) Does every collision between reacting particles lead to products? 17) What is entropy? 18) What is enthalpy? Performance Levels Learning Progressions 1) Students will evaluate the energy changes that occur with physical and chemical changes. Prerequisite Knowledge: Students will calculate the amount of heat absorbed or released per mole of chemical reaction. 1) Students will interpret the heating curve of water at any given temperature and pressure. 2) Students will explain the relationship between energy and heat. 3) Students will distinguish between heat capacity and specific heat. 4) Students will construct equations that show the heat changes for chemical and physical processes. 5) Students will classify and calculate, by type, the heat changes Performance Levels 1) Students will evaluate the behavior of gases based on the kinetic molecular theory. Prerequisite Knowledge: Students will describe the postulates of the kinetic molecular theory. Learning Progressions 1) Students will describe the motion of gas particles according to the kinetic theory. 2) Students will interpret gas pressure in terms of kinetic theory. 3) Students will describe the properties of gas particles. 4) Students will explain how the kinetic energy of gas particles relates to Kelvin temperature. 5) Students will explain how the amount of gas and the volume of the container affect gas pressure. 5

6 representative particles, and volumes of gases at STP. 4) Students will determine the limiting reactant and calculate the excess reagent. 5) Students will calculate percent yield using actual and theoretical yields. that occur during melting, freezing, boiling, and condensing. 6) Students will apply Hess s Law of heat summation to find heat changes for chemical and physical processes. 7) Students will calculate heat changes using standard heats of formation. 6) Students will infer the effect of temperature changes on the pressure exerted by a contained gas. 7) Students will state Boyle s Law, Charles Law, Gay- Lussac s Law, and the combined gas law. 8) Students will apply the gas laws to problems, involving the temperature, volume, and pressure of a contained gas. 9) Students will calculate the amount of gas at any specified conditions of pressure, volume, and temperature. 10) Students will distinguish between ideal and real gases. 11) Students will state Avogadro s hypothesis, Dalton s Law, and Graham s Law. 6

7 12) Students will calculate moles, masses, and volumes of gases at STP. 13) Students will calculate partial pressures and compare rates of effusion. Concepts Limiting and Excess Reagents Thermodynamics and activation energy Gas Laws and Kinetics Topics Limiting Reagents Heat Transfer: Convection, Boyle s Law Excess Regents Conduction, and Radiation Charles Law Percent Yield Specific Heat Gay-Lussac s Law Actual Yield H, Enthalpy, Heat of Reaction Combined Gas Law Theoretical Yield Endothermic/Exothermic Ideal Gas Law Rates of Reaction Avogadro s Hypothesis Activation Energy Diagrams Dalton s Law of Partial Pressures Q = mc T Graham s Law Phase Diagrams Kinetic Molecular Theory Triple Point and Critical Point Pressure Systems (atm, torr, Phase Changes mmhg, kpa) Entropy Enthalpy Activation Energy Essential Facts 1) Whenever the quantities of two or more reactants are given in a stoichiometry problem, the limiting reagent must be identified. 2) A limiting reagent is completely used up in a chemical reaction. 3) The amount of limiting reagent determines the amount of product formed in a chemical reaction. 1) Most substances change their physical state and melt or vaporize as the temperature increases. Substances condense or freeze as the temperature decreases. 2) While the physical state of a substance changes during a phase change, the temperature of the system remains constant. 1) The kinetic theory describes the motion of particles (atoms, ions, or molecules) in matter and the forces of attraction between them. 2) The kinetic theory assumes that the volume occupied by a gas is mostly empty space and that the particles of a gas are far apart, move rapidly, and have random motion. 7

8 4) If there is a single limiting reagent in a reaction all the other reactants are in excess. 5) A theoretical yield is the maximum amount of product that can be obtained from a given amount of reactants in a chemical reaction. 6) An actual yield is the amount of product obtained when the reaction is carried out in the laboratory. 7) A ratio of the actual yield to the theoretical yield, expressed as a percentage, is the percent yield of a reaction. 3) In sublimation, a solid can change directly to a gas or vapor without first becoming a liquid. 4) Energy is the capacity to do work or to supply heat. The law of conservation of energy states the energy cannot be created or destroyed. 5) A process is exothermic if heat flows from the system to the surroundings and endothermic if heat flows from the surroundings to the system. 6) An object s heat capacity is the amount of heat it takes to change the object s temperature by exactly 1 C. The specific heat capacity of a substance is the amount of heat it takes to raise the temperature of 1 g of the substance 1 C. 7) Thermochemical equations show the accompanying heat of reaction at constant pressure. 8) Calorimetry measures heat changes associated with chemical reactions and phase changes. 9) The molar heats of fusion, solidification, vaporization, and condensation describe the quantity of heat transferred to or from a system when one mole of substance undergoes a change of state at constant temperature. 10) Hess s law states that in a reaction that is the sum of two or more other reactions, ΔH for the overall process is the sum of the ΔH values for all of the constituent reactions. 11) The enthalpy for the formation of one 3) The pressure of a gas results from the collisions of the gas particles with an object. 4) Standard conditions are 0 C and 1 atm. 5) The temperature of a gas is directly proportional to the average kinetic energy of the particles. 6) Kinetic molecular theory can be used to explain gas pressure, volume, and temperature. 7) The average kinetic energy of a collection of gas particles is directly proportional to the Kelvin temperature of the gas. 8) The collision of gas particles with the walls of the container constitutes gas pressure. 9) In general, increasing the temperature of a contained gas increases its pressure; decreasing the temperature of contained gas increases its pressure; decreasing the temperature decreases its pressure. 10) The pressure and volume of a fixed mass of gas are inversely related (Boyle s Law). 11) The volume of a gas at constant pressure is directly related to its Kelvin temperature (Charles Law). 12) The pressure of a fixed volume of gas is directly related to its Kelvin temperature (Gay-Lussac s Law). 13) The ideal gas law relates the moles of a gas to its pressure, temperature, and volume. 14) Real gases differ from ideal gases 8

9 mole of a compound from its elements in standard states is the enthalpy of formation (H f 0 ). 12) The standard enthalpy change for a reaction (ΔH 0 ) can be calculated from the H f 0 of the reactants and products. 13) The rate at which a chemical reaction proceeds is determined by the number of collisions between reacting particles and the energy with which the particles collide. 14) The natural tendency for all the things to go to lower heat content (enthalpy) and greater randomness (entropy) determines whether a reaction will occur (is spontaneous). because intermolecular forces tend to reduce the distance between real gas particles and because real gas particles have volume. 15) Avogadro stated that equal volumes of gases, at the same temperature and pressure, contain an equal number of particles. 16) The total pressure in a mixture of gases is equal to the sum of the partial pressures of each gas present (Dalton s Law) 17) Gases diffuse from a region of high gas concentration to one of lower gas concentration. The smaller the molar mass of a gas, the greater its rate of diffusion (Graham s Law). Processes and Skills 1) Identify and use the limiting reagent in a reaction to calculate the maximum amount of product(s) produced and the amount of excess reagent. 2) Calculate theoretical yield, actual yield, or percent yield given appropriate information. 1) Interpret the phase diagram of water at any given temperature and pressure. 2) Describe the behavior of solids that change directly to the vapor state and recondense to solids without passing through the liquid state. 3) Explain the relationship between energy and heat. 4) Distinguish between heat capacity and specific heat. 5) Construct equations that show the heat changes for chemical and physical processes. 6) Calculate heat changes in chemical and physical processes. 7) Classify, by type, the heat changes that occur during melting, freezing, boiling, and 1) Describe the motion of gas particles according to the kinetic theory. 2) Interpret gas pressure in terms of kinetic theory. 3) Describe the properties of gas particles. 4) Explain how the kinetic energy of gas particles relates to Kelvin temperature. 5) Explain how the amount of gas and the volume of the container affect gas pressure. 6) Infer the effect of temperature changes on the pressure exerted by a contained gas. 7) State Boyle s Law, Charles Law, Gay- Lussac s Law, and the combined gas law. 8) Apply the gas laws to problems, involving the temperature, volume, and 9

10 Language of Instruction Formative Assessment (for learning) Actual Yield, Excess Reagent, Limiting Reagent, Percent Yield, and Theoretical Yield. Limiting Reagents Stated Question or Quiz WebAssign condensing. 8) Calculate heat changes that occur during melting, freezing, boiling, and condensing. 9) Apply Hess s Law of heat summation to find heat changes for chemical and physical processes. 10) Calculate heat changes using standard heats of formation. Phase Diagram, Triple Point, Critical Point, Sublimation, Calorie, Calorimeter, Calorimetry, Chemical Potential Energy, Endothermic Process, Energy, Enthalpy, Exothermic Process, Heat, Heat Capacity, Heat of Combustion, Heat of Reaction, Hess s Law of Heat Summation, Joule, Law of Conservation of Energy, Molar Heat of Condensation, Molar Heat of Fusion, Molar Heat of Solidification, Molar Heat of Solution, Molar Heat of Vaporization, Specific Heat, Specific Heat Capacity, Standard Heat of Formation, Thermochemical Equation, and Thermochemistry, enthalpy, entropy, and activation energy Thermochemistry Stated Question or Quiz WebAssign pressure of a contained gas. 9) Calculate the amount of gas at any specified conditions of pressure, volume, and temperature. 10) Distinguish between ideal and real gases. 11) State Avogadro s hypothesis, Dalton s Law, and Graham s Law. 12) Calculate moles, masses, and volumes of gases at STP. 13) Calculate partial pressures and compare rates of effusion. Kinetic Energy, Kinetic Theory, Gas Pressure, Vacuum, Atmospheric Pressure, Barometers, Pascal, Standard Atmosphere, Avogadro s Hypothesis, Boyle s Law, Charles s Law, Combined Gas Law, Compressibility, Dalton s Law of Partial Pressures, Diffusion, Effusion, Gay-Lussac s Law, Graham s Law of Effusion, and Ideal Gas Law. Reading Quiz WebAssign Summative Assessment (of learning) Limiting Reagent Test Thermochemistry Test Gas Laws Test 10

11 Required Lab Baking Soda Stoichiometry and Limiting Reagent Lab Heat of Fusion of Ice Lab Specific Heat Lab Boyle s Law Probe Lab Lighter Lab (Ideal Gas Law) Other Resources 100 Reproducible Activities: Chemistry by Instructional Fair, Inc (workbook) p Reproducible Activities: Chemistry by Instructional Fair, Inc (workbook) p. 12, 13, 14, 15, Reproducible Activities: Chemistry by Instructional Fair, Inc (workbook) p. 20,21,22,23,24, Reproducible Activities: Physical Science by Instructional Fair, Inc (workbook) p. 25, 26 Textbook Correlation Chapter 9 Chapters 10, 11 Chapter 12 Challenge/Extension Link to Medicine p. 272 Link to Food Science p. 285 Link to Physics p. 345 Link to Physiology p. 296 Link to Biology p. 306 Other Curricular Connection (ELA, Math, S.S., Technology) Chemistry Serving the Environment p. 287 Chemistry in Careers (Climatologist) p Chemistry Serving the Environment p Chemistry in Careers (Solar Engineer) p Chemistry Serving Industry p. 354 Chemistry in Careers (Commercial Diver) p