Focus Plan Texarkana Independent School District PLAN CODE: WRITER: IPC – 5th six weeks, Biology – 1st six weeks, Chemistry – 4th six weeks L. Petty COURSE/SUBJECT: 10th grade science GRADE(S): 10th TIME ALLOTTED FOR INSTRUCTION: 1½ hours GRADING PERIOD: TITLE: Pass The Salt LESSON TOPIC: What factors affect the solubility of a substance. TAKS OBJECTIVE: Objective 4 The student will demonstrate an understanding of the structures and properties of matter. 10.9 The student knows how solution chemistry is a part of everyday life. The student is expected to: (D) demonstrate how various factors influence solubility including temperature, pressure, and nature of the solute and solvent. 10.1 The student, for at least 40% of instructional time, conducts field and laboratory investigations using safe, environmentally appropriate, and ethical practices. The student is expected to: (A) demonstrate safe practices during field and laboratory investigations 10.2 The student uses scientific methods during field and laboratory investigations. The student is expected to: (A) plan and implement investigative procedures including asking questions, formulating testable hypotheses, and selecting equipment and technology (B) collect data and make measurements with precision (C) organize, analyze, evaluate, make inferences, and predict trends from data (D) communicate valid conclusions FOCUS TEKS AND STUDENT EXPECTATION: SUPPORTING TEKS AND STUDENT EXPECTATIONS: CONCEPTS Chemistry ENDURING UNDERSTANDINGS/GENERALIZATIONS/PRINCIPLES The student will understand that Solution chemistry is a part of everyday life. Solutions A solute dissolves in a solvent to form a solution. Ionic solid An ionic solid will usually separate when mixed with water to form charged ions. Polarity Because water is a polar solvent, ionic solutes typical form solutions in water. Solubility Factors such as temperature, particle size, nature of the solute and solvent and agitation affect how quickly a solute will dissolve. I. SEQUENCE OF ACTIVITIES (INSTRUCTIONAL STRATEGIES) A. Focus/connections/anticipatory set When students arrive, have a nice big glass of iced tea on your desk (for added effect, include a straw, little umbrella, etc). Pick it up and take a sip. Say “There’s nothing like a nice glass of tea on a hot day, but this wouldn’t be quite so good without a little understanding of science.” Explain that, in order to have a glass of tea, things have to dissolve. In order to have a GOOD glass of tea, you need to understand HOW things dissolve. B. Instructional activities (demonstrations, lectures, examples, hands-on experiences, role play, active learning experience, art, music, modeling, discussion, reading, listening, viewing, etc.) Give students about 5 minutes to work with their lab partner to brainstorm what might cause materials to dissolve better. Tell them to think of a substance such as sugar to use as an example. Once they are done, list these ideas on the board. Pick out a couple to test. (They should have included stirring, using smaller particles and/or temperature since these are the three they may have encountered in school or at home if they have ever made tea.) C. Guided activity or strategy Have materials set up to test either stirring (2 equal amounts of granulated sugar with 2 beakers of water and a stirring rod) or smaller particles (2 beakers of water with a sugar cube and equal amount of granulated sugar). Have students come up and demonstrate both of these ideas. Explain to students that they have looked at two factors. The effect of temperature is the purpose of their lab. D. Accommodations/modifications Students requiring accommodations should be paired with a peer tutor. E. Enrichment Students requiring enrichment should act as peer tutors. II. STUDENT PERFORMANCE A. Description Students should complete Lab – Pass The Salt B. Accommodations/modifications Students requiring accommodations should be assigned a peer tutor. C. Enrichment Students requiring enrichment should be assigned as peer tutors. Students requiring enrichment may also be assigned a third solid to test or may test another variable such as size of the solute (using regular and rock salt). III. ASSESSMENT OF ACTIVITIES A. Description Complete Lab Worksheet – Pass The Salt B. Rubrics/grading criteria Data tables should be graded as 2 points a space. Questions with only one part (3, 6, 7, 8 and synthesis) should count as 4 points each. All other questions should count as 2 points for each part. Questions left blank or answered incorrectly should have these points deducted. C. Accommodations/modifications Students requiring accommodations may either be excused from doing the synthesis questions or should be graded on a more lenient scale. D. Enrichment Students requiring enrichment should do all questions. E. Sample discussion questions 1. If you like sweet tea, how would you get the most sugar to dissolve? Stir it, use granulated sugar and/or add the sugar to the tea when it is still warm. 2. If you like your tea to be strong, what would you do? Stir it or make the tea with warm or hot water. 3. You like strong, sweet tea. Describe the best way to make your tea. Put the tea bags into a pitcher of hot water. Gently stir it so that you don’t break the tea bags. Once it is strong enough (dark enough), remove the tea bags and immediately add sugar to the proper sweetness. Stir the sugar until it dissolves. Put the tea into the refrigerator so that it can get cold before serving so that it won’t melt your ice and get too diluted. IV. TAKS PREPARATION A. Transition to TAKS context 1. Temperature is one of several factors that affects the solubility of a compound in water. Based on the graph shown above, which of the following is the most accurate description of a relationship between water temperature and the solubility of a compound? (a) The solubility of KNO3 increases by the same percentage as the solubility of NaNO3 when the water temperature increases. (b) The solubility of Na2SO4 and NaCl are affected in the same manner when the water temperature increases. (c) The solubility of KNO3 increases by a greater percentage than the solubility of NaNO 3 when the water temperature increases. (d) The solubility of KBr and NH4Cl increase by the lowest percentage when the water temperature increases. 2. The effect of solvent temperature on solubility can be plotted on a graph. Based on the graph shown above, which compound will exhibit the greatest decrease in solubility as the water temperature drops from 60oC to 40oC. (a) NH4Cl (b) NaNO3 (c) Na2SO4 (d) KNO3 3. The effect of water temperature on the solubility of several compounds is plotted on the graph below. Based on the graph shown above, which of the following is the most accurate description of a relationship between temperature and the solubility of a compound? (a) Most compounds exhibit an increase in solubility as the water temperature increases. (b) All compounds exhibit an increase in solubility as the water temperature increases. (c) Few compounds exhibit an increase in solubility as the water temperature increases. (d) Most compounds exhibit a decrease in solubility as the water temperature increases. B. Sample TAKS questions Spring 2004 1. As a scuba diver goes deeper underwater, the diver must be aware that the increased pressure affects the human body by increasing the _____. (a) body’s temperature (b) amount of dissolved gases in the body (c) amount of suspended solids in the body (d) concentration of minerals in the body V. KEY VOCABULARY solute solvent solubility VI. RESOURCES A. Textbook None needed B. Supplementary materials/equipment Lab Instructions – Pass The Salt Lab Worksheet – Pass The Salt Instructor’s Copy Lab Worksheet – Pass The Salt C. VII. Technology FOLLOW UP ACTIVITIES (reteaching, cross-curricular support, technology activities, next lesson in sequence, etc.) A. Reteaching Go over student’s graded lab worksheets. B. Next lesson in sequence IPC – 9D Demonstrate how factors such as particle size, influence the rate of dissolving. Biology – 11A Identify and describe the relationships between internal feedback mechanisms in the maintenance of homeostasis. Chemistry – 12B Develop general rules for solubility through investigations with aqueous solutions VIII. TEACHER NOTES Before lab: 1. Assemble that materials for the guided activity but keep them hidden so students don’t get any hints about the setup. 2. Run off a class set of the lab instructions. (30-35) 3. Run off a lab worksheet for each student. 4. Decide if students will be heating the water or whether they will get the hot water from a beaker heated by the teacher. If the teacher will be heating the water, adapt the instructions accordingly. 5. Caution students to check their glassware for chips and cracks. Replace any as needed. During lab: 6. Make sure students are wearing their goggles. 7. Caution them about dealing with hot water. 8. Monitor students as they work with hot plates. 9. Make sure the club soda is closed when not being poured so that it doesn’t go flat. Lab is adapted from “Factors Affecting Solubility” in Heath Chemistry Laboratory Experiments, 1993 edition.