Science Grade 08 Unit 04 Exemplar Lesson 01: Formulas, Equations, and the Conservation of Mass

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1 Unit: 04 Lesson: 01 Suggested Duration: 15 days Grade 08 Unit 04 Exemplar Lesson 01: Formulas, Equations, and the Conservation of Mass This lesson is one approach to teaching the State Standards associated with this unit. Districts are encouraged to customize this lesson by supplementing with district-approved resources, materials, and activities to best meet the needs of learners. The duration for this lesson is only a recommendation, and districts may modify the time frame to meet students needs. To better understand how your district may be implementing CSCOPE lessons, please contact your child s teacher. (For your convenience, please find linked the TEA Commissioner s List of State Board of Education Approved Instructional Resources and Midcycle State Adopted Instructional Materials.) Lesson Synopsis Chemical formulas containing subscripts and preceded by coefficients will be analyzed and interpreted to determine the number of atoms of each element present in compounds. Students will implement investigations and observe evidence of chemical reactions as indicators of the formation of new substances with differing properties. Students will also recognize the components of a chemical equation and understand that chemical equations represent what occurs in a chemical reaction. The relationship between balanced equations and the law of conservation of mass will be examined, and students will recognize that a balanced chemical equation expresses what happened in a chemical reaction. TEKS The Texas Essential Knowledge and Skills (TEKS) listed below are the standards adopted by the State Board of Education, which are required by Texas law. Any standard that has a strike-through (e.g. sample phrase) indicates that portion of the standard is taught in a previous or subsequent unit. The TEKS are available on the Texas Education Agency website at id=6148. Scientific Process TEKS 8.5 Matter and energy. The student knows that matter is composed of atoms and has chemical and physical properties. The student is expected to: 8.5D Recognize that chemical formulas are used to identify substances and determine the number of atoms of each element in chemical formulas containing subscripts. Readiness Standard 8.5E Investigate how evidence of chemical reactions indicate that new substances with different properties are formed. Readiness Standard 8.5F Recognize whether a chemical equation containing coefficients is balanced or not and how that relates to the law of conservation of mass. Supporting Standard 8.2 Scientific investigation and reasoning. The student uses scientific inquiry methods during laboratory and field investigations. The student is expected to: 8.2C Collect and record data using the International System of Units (SI) and qualitative means such as labeled drawings, writing, and graphic organizers. 8.2E Analyze data to formulate reasonable explanations, communicate valid conclusions supported by the data, and predict trends. 8.3 Scientific investigation and reasoning. The student uses critical thinking, scientific reasoning, and problem solving to make informed decisions and knows the contributions of relevant scientists. The student is expected to: 8.3B Use models to represent aspects of the natural world such as an atom, a molecule, space, or a geologic feature. 8.3C Identify advantages and limitations of models such as size, scale, properties, and materials. 8.4 Scientific investigation and reasoning. The student knows how to use a variety of tools and safety equipment to conduct science inquiry. The student is expected to: 8.4A Use appropriate tools to collect, record, and analyze information, including lab journals/notebooks, beakers, meter sticks, graduated cylinders, anemometers, psychrometers, hot plates, test tubes, spring scales, balances, microscopes, thermometers, calculators, computers, spectroscopes, timing devices, and other equipment as needed to teach the curriculum. Last Updated 04/24/13 page 1 of 49

2 GETTING READY FOR INSTRUCTION Unit: 04 Lesson: 01 Suggested Duration: 15 days Performance Indicators Grade 08 Unit 04 PI 01 Create a manual to show how to break down a chemical equation into components. For each component of the equation, include detailed steps on how to determine its composition. Use data collected throughout the unit to present evidence that a chemical change took place during the reaction, represented by the chemical equation. Include a page in the manual that lists the types of evidence that can be used to indicate that a chemical change had taken place and a summary of the relationship of the balanced equation to the law of conservation of mass. Standard(s): 8.2C, 8.2E, 8.5D, 8.5E, 8.5F ELPS ELPS.c.1E, ELPS.c.5D, ELPS.c.5G Key Understandings Chemical formulas can be used to determine the number of atoms of each element found in compounds. How are chemical formulas used to determine the number of atoms of each element found in compounds? What is the purpose of a subscript in a chemical formula? What is the purpose of coefficients in a chemical formula? Chemical reactions indicate that new substances with different properties are formed. What evidences indicate that a new substance has formed as a result of a chemical reaction? What are the components of a chemical equation? After a reaction, how do the reactants and products in a chemical equation compare? A balanced equation represents the law of conservation of mass or that every atom present at the start of the reaction is still present at the end of the reaction. How are balanced chemical equations and the law of conservation of mass related? What is meant by balanced equation? Vocabulary of Instruction chemical change chemical formula chemical equation subscript coefficient product reactant yield law of conservation of mass precipitate chemical reaction physical change Materials bags of blocks (for Station 3, see Advance Preparation) baking soda balance (1 per group) balloon (1 per group, for Optional Handout: It s the Law) beaker (250 ml per group) block of wood (1 per group) blocks (various colors per group, for Optional Handout: It s the Law) coins or play money (various denominations, 24 per group) colored markers or pencils (per pair) cream of tartar (0.6 g per group) cups labeled ABC (clear, plastic, 3 per group) Epsom salts (MgSO4) (5 g per group) funnel (1 per group, for Optional Handout: It s the Law) graduated cylinders (2 per group) matches (per group) MSDS (vinegar and baking soda, 1 each per class) non-sudsy household ammonia (NH4OH) (10 ml per group) paper (copy, several pages per student) paper lunch bag (1 per group) periodic table (1 per group, see Resources and References section) plaster of Paris (236 g per group) plastic water or soda bottle (1 per group, for Optional Handout: It s the Law) powdered laundry detergent (0.6 g per group) red cabbage leaves (2 per group) resealable plastic bag (quart-size, 1 per group) resealable plastic bags (quart-size, freezer weight) Last Updated 04/24/13 page 2 of 49

3 resealable plastic bags of blocks (centigram/cc blocks, various colors, see Advance Preparation, 1 set per group) safety goggles (1 per student) spoon (plastic, 1 per group) stapler (per class) stirrers tape (masking,1 roll per group) tape or glue (per pair) thermometer (1 per group) timer (1 per group) triple beam balance, for Optional Handout: It s the Law) vinegar votive or tea candle (1 per group) water Unit: 04 Lesson: 01 Suggested Duration: 15 days Attachments All attachments associated with this lesson are referenced in the body of the lesson. Due to considerations for grading or student assessment, attachments that are connected with Performance Indicators or serve as answer keys are available in the district site and are not accessible on the public website. Handout: Chemistry Language Cards (see Adv. Prep., 1 set per pair/triad of students) Teacher Resource: Engage Investigation: Components of Chemical Equations Part I (1 for projection) Teacher Resource: Engage Investigation: Components of Chemical Equations Part I KEY (1 for projectio Teacher Resource: Evidence of Chemical Change (1 for projection) Handout: Lights Out (1 per group) Teacher Resource: Lights Out KEY Handout: Dropping Out (1 per group) Teacher Resource: Dropping Out KEY Handout: Changing Temperature (1 per group) Handout: Signs of a Chemical Reaction (1 per student) Teacher Resource: Signs of a Chemical Reaction KEY Handout: Decoding Chemical Formulas (1 per student) Teacher Resource: Decoding Chemical Formulas KEY (1 for projection) Teacher Resource: Modeling Chemical Formulas (1 for projection) Teacher Resource: Modeling Chemical Formulas KEY Handout: Counting Atoms (1 per student) Teacher Resource: Counting Atoms KEY Handout: What s the Count? (1 per student) Teacher Resource: What s the Count? KEY Optional Handout: It s the Law (1 per student) Optional: Teacher Resource: It s the Law KEY Handout: Balanced? (1 per student) Teacher Resource: Balanced? KEY (1 per teacher) Resources None Identified Advance Preparation 1. Prior to Day 1, measure and prepare all ingredients as Solid A and Solid B and Liquid A and Liquid B with 5 grams of baking soda in each bag, 10 ml of water in graduated cylinder A, and 10 ml of vinegar in graduated cylinder B. Prepare for as many groups as needed throughout the day. Take into consideration that ingredients will need to be replaced for each class period. For example, eight lab groups per class multiplied by six class periods equals preparation for 48 individual groups. 2. Prior to Day 1, copy Handout: Chemistry Language Cards on cardstock. Create a class set with enough for each pair/triad student Last Updated 04/24/13 page 3 of 49

4 group to have a set. Laminate and cut the words and definitions apart, and place each set in a resealable, plastic bag. Bags can be reused each class period. 3. Prior to Day 7, purchase one fresh head of red cabbage; pre-shredded red cabbage will not work. This red cabbage will be used to make indicator solution for the Color Switch lab activity. Refrigerate the cabbage so that it will stay fresh. 4. Prior to Day 8, prepare bags of colored blocks with a color code for the Teacher Resource: Modeling Chemical Formulas and Handout: Counting Atoms stations. Prepare resealable plastic bags of blocks for students to construct models of the formulas listed on the Handout: Counting Atoms. Prepare six bags (one for each formula), and set up six stations for students to rotate through. Provide a color key at each station. Students should carry their handout to each station. 5. Copy in color, laminate, cut out, and place in resealable, plastic bags Teacher Resource: Review Stations (2 sets per station). Prepare bags of colored blocks for Station 3 and provide a color code. Stations: 1. Chemical/Physical Change 2. Components of Equations 3. Modeling Formulas (Prepare the bags of blocks.) 4. Balanced or Unbalanced? 5. Modeling Equations 6. Chemical Language Cards (previously used in lessons) 6. Prepare attachment(s) as necessary. Background Information This unit bundles student expectations addressing how formulas indicate the number of atoms in a substance and how balanced equations show the law of conservation of mass in a chemical reaction. Unit: 04 Lesson: 01 Suggested Duration: 15 days Students have had very limited exposure to chemical formulas or equations. In prior units, in, students have studied the structure of atoms and learned to interpret the arrangement of the periodic table. During this unit, students learn to recognize the use of chemical formulas to identify substances and determine numbers of atoms in elements. They investigate evidence of chemical reactions as indicators of the formation of new substances with differing properties. Students recognize that chemical formulas and balanced equations represent what happens in a chemical reaction and how balanced equations relate to the law of conservation of mass Students will investigate evidences that a new substance has formed as the result of a chemical reaction: the appearance of bubbles or change in odor indicating production of gas, formation of a precipitate, temperature changes, and color changes. STAAR Notes: Chemical formulas and reactions (8.5D, 8.5E) will be assessed as Readiness Standards under Reporting Category 1: Matter and Energy on the STAAR Assessment. Equations and the relationship to the law of conservation of mass (8.5F) will be assessed as a Supporting Standard under Reporting Category 1: Matter and Energy on the STAAR Assessment. INSTRUCTIONAL PROCEDURES Instructional Procedures ENGAGE So What? 1. Divide the class into groups. Distribute materials to each group (see Advance Preparation). 2. Explain to students they will be working with mystery substances that will be revealed to them later in the lesson. 3. Review chemical safety at this time. Eye protection must be worn when working with chemicals. MSDS for vinegar and baking soda must be available. 4. Instruct students to do the following in their groups. It may be helpful to display these on the board: Observe and describe the substances in your science notebook before beginning the investigation. Be sure to indicate which is A and which is B. The bags are labeled A and B. Do not mix the two bags. Add the 10 ml of Liquid A to the bag labeled A, and seal the bag quickly. Gently knead the bag. Record your observations. Add the 10 ml of Liquid B to the bag labeled B, and seal bag quickly. Gently knead the bag. Record observations. Observe and describe the substances after the mixing occurs; record what you see and feel after steps 3 and 4. Notes for Teacher NOTE: 1 Day = 50 minutes Suggested Day 1 Materials: resealable plastic bags (see Advance Preparation for preparation of bags, 2 per group) baking soda (10 g per group for Bags A and B) graduated cylinders (2 per group) vinegar (10 ml per group for Bag B) water (H 2 O) (10 ml per group for Bag A) safety goggles (1 per student) MSDS (vinegar and baking soda, 1 each per class) Safety Notes: Review chemical safety at this time. Last Updated 04/24/13 page 4 of 49

5 Unit: 04 Lesson: 01 Suggested Duration: 15 days 5. Instruct students to discuss the following in their group. Ask: What did you observe? What do you think caused the difference in the bags? Provide supporting evidence for your explanation. Answers will vary, but students should indicate that a chemical reaction happened in bag B, but not in bag A. They should cite some type of supporting evidence such as gas production, fizzing, bubbling, temperature change, a new substance formed, etc. 6. Monitor and facilitate group discussions. Ask students to explain why and how they came up with their answers. 7. Instruct students to record their explanations and supporting evidence in their science notebooks. 8. Explain to students that the class will spend the next few weeks exploring, learning, understanding, and explaining exactly what happened and did not happen in the bags today. Eye protection must be worn when working with chemicals. MSDS for vinegar and baking soda must be available. Instructional Notes: You may wish to use a discussion strategy that requires each group member to contribute. For example, the oldest member begins and then the discussion moves to the right around the table. No one can speak out of turn, but everyone must speak. The group needs to come to consensus about what occurred and cite evidence prior to recording in their notebooks. Notebooks: Students should record before and after observations, as well as explanations of what happened-including evidence- in their notebooks. 9. Explain to students they will come back to this investigation multiple times throughout the unit, and they should be comfortable explaining the situation in terms of chemical equations, chemical reactions, balanced equations, and the law of conservation of mass by the end of the unit. EXPLORE/EXPLAIN Using Chemistry Language Suggested Days 1 (continued), 2, and 3 1. Divide the class into groups of pairs or triads. Distribute a set of Chemistry Language Cards (see Advance Preparation) to each group. 2. Instruct students to work collaboratively and match the words with the definitions. 3. Monitor student displays for accuracy. If students have displayed an incorrect match, encourage them to try again. 4. After students have correctly matched pairs, instruct them to take turns quizzing one another while other groups complete their task. 5. Project the Teacher Resource: Engage Investigation Components of Chemical Equations Part I. Students should copy the equations for bags A and B in their science notebooks. 6. Say: Chemical equations are a shorthand way that scientists use to represent what takes place in a chemical reaction. Chemical equations consist of many components (parts). 7. Instruct students work with a partner and use the Chemistry Language Cards to try and determine the different components of a chemical equation. 8. Monitor students for accuracy. Students may be compelled to go ahead and label subscripts, symbols, etc. If they do so, explain that you will be addressing those components in a future lesson. 9. Once students have correctly identified the parts of the chemical equation, instruct them to label the equations in their notebooks. Project the Teacher Resource: Engage Investigation Components of Chemical Equations Part I KEY for students to check their work. 10. Instruct students to work with a partner to compare and contrast the chemical equations for bags A and B. Students should set up a table/chart in their notebooks to show similarities and differences. Explain that they should be prepared to share their findings with the large group. 11. Facilitate a brief large group discussion in which students reflect on the similarities and differences of the two equations. Insure each group shares. Ask: Attachments: Handout: Chemistry Language Cards (see Advance Preparation, 1 set per pair/triad of students) Teacher Resource: Engage Investigation: Components of Chemical Equations Part I (1 for projection) Teacher Resource: Engage Investigation: Components of Chemical Equations Part I KEY (1 for projection) Instructional Notes: Consider grouping high and medium; medium and low students for this activity. If you have a co-teacher or inclusion support person, consider having them work with a small group if necessary. Encourage students to add to their explanations in their notebooks as the large group shares out. They can make a mark to indicate where their answer ends and new information begins. Check For Understanding: The Chemistry Language Cards compare/contrast question serves as a pre assessment. This will create a need to know for students throughout the unit, and help the teacher modify instruction as needed. Notebooks: Students record chemical equations for Bags A and B with labeled parts of a chemical equation. Students compare/contrast chemical equations for bags A and B and answer reflective questions in their notebooks. Last Updated 04/24/13 page 5 of 49

6 What was alike/different in the two equations? They both have the same component parts; NaHCO 3 was a reactant in both equations. There were no substances in A, while the products and reactants were different in B. Did a chemical reaction take place in bag A? How do you know? No, a new substance did not form. Did a chemical reaction take place in bag B? How do you know? Yes, the reactants and products differ. The arrangement of elements is different. How do the reactants and products differ in equation A? The reactants and products do not differ What does this mean? This means that a chemical reaction/change did not take place. A new substance was not formed. How do the reactants and products differ in equation B? There are no new products because a chemical reaction did not take place. What does this mean? A chemical reaction/change occurred, and a new substance was formed. Unit: 04 Lesson: 01 Suggested Duration: 15 days 12. Project the following question on the board. Ask students to use their notebooks and Chemistry Language Cards to answer the question in their notebooks. Remind students to use complete sentences. Ask: How do the chemical equations for bags A and B explain what did or did not happen in our investigations? 13. Monitor and facilitate groups as they work. 14. Different groups will finish at different rates, so instruct students to paraphrase and record vocabulary terms and definitions in their science notebooks. They should focus on the terms used during this lesson. Make the cards available during all times throughout the lesson, so students may have the opportunity to continue this task during transitional times. EXPLORE /EXPLAIN Gas Production Suggested Day 4 1. Review evidence of chemical changes (previously learned in Grade 6). Ask: What is a chemical change? When substance(s) change into new substances with new properties as a result of a chemical reaction How do we know when a chemical change has taken place? What s the proof? Gas production, bubbles, temperature change, color change, light production, formation of a precipitate Did a chemical change happen in bags A and B? How do you know? What was your proof? (Students may refer to their notebooks.) Bag A No; Bag B Yes: gas production, bubbles, temperature change 2. Project the Teacher Resource: Evidence of Chemical Change. Instruct students to record the following memory device in their science notebooks. Explain how this simple phrase will help them remember the evidences of chemical change. City (country) Girls (guys) Love Their Phones. Color change Gas production Light production Temperature change Precipitate formation 3. Explain that these occurrences are the pieces of evidence that we must look for to determine if a chemical change has happened. Inform students that they should always be prepared to cite one or more of these evidences as justification for claiming that a chemical change took place. Note that a color change or a temperature change does not always indicate a chemical reaction. Materials: beaker (250 ml per group) balance (1 per group) baking soda (3 g per group) vinegar (50 ml per group) stirrer (1 per group) votive or tea candle (1 per group) block of wood (1 per group) matches (per group) safety goggles (1 per student) graduated cylinder (1 per group) Attachments: Teacher Resource: Evidence of Chemical Change (1 for projection) Handout: Lights Out (1 per group) Teacher Resource: Lights Out KEY Safety Notes: Vinegar is a weak acid. Have an MSDS available for vinegar. Eye protection must be worn when working with chemicals. Never taste any substances in the lab. Last Updated 04/24/13 page 6 of 49

7 4. Divide the class into groups. You may wish to use the same groups from Day 1. Distribute the Handout: Lights Out to each group. 5. Prior to conducting the activity, ask students to read the handout and prepare a page in their science notebooks. Answer any questions they may have about the instructions. 6. Instruct students to create a before/after data table in their notebooks to record observations/data throughout the investigation. They should include the substances, amounts, and characteristics/properties. Require students to answer all questions in complete sentences in their notebooks. 7. Discuss safety rules and procedures for working with a flame and an acid with students. See the Safety Notes. 8. Distribute materials to each group. 9. Monitor students during the activity, and require them to clean up their lab stations when finished. For disposal, the mixture may be diluted with water and poured down the sink drain. 10. Facilitate a class discussion using the following questions. Encourage each group to share their findings with the class, but do not ask all four questions of each group. Ask: Did a chemical change occur? Yes What is your evidence? The substance became cloudy and a white solid formed and began to fall to the bottom of the beaker over time; a precipitate formed. How can you prove that a gas was produced? The candle was extinguished; bubbles formed. How do the properties of the original substances compare to the new substance? Clear liquid; white powder - clear liquid Remind students that wafting is the proper way to smell a substance and to only do so when instructed by the teacher. When working with flames, hair and loose clothing should be secured. Be sure to point out the location of the fire extinguisher, fire blanket, and eyewash stations. Instructional Notes: Students may confuse bubbles from boiling a liquid with bubbles from gas production. Change of state is a physical change. Students may confuse the addition of food coloring to water with color change. A color change is when a NEW and different color results from mixing two substances. Provide many examples and nonexamples for comparison. Notebooks: Students record the memory device, data, observations, and answer questions about this activity in their notebooks. Students write a summary of the investigation in their notebooks. Unit: 04 Lesson: 01 Suggested Duration: 15 days 11. Instruct students to write a one paragraph summary of the investigation in their notebooks by using their data/observations and the answers to their questions. Encourage students to use the Chemistry Language Cards and Evidence of Chemical Change notes. EXPLORE/EXPLAIN Precipitate Suggested Day 5 1. Project the following chemical equation: NaHCO 3 + HC 2 H 3 O 2 CO 2 + H 2 O + NaC 2 H 3 O 2 baking soda + vinegar yields carbon dioxide + water + sodium acetate 2. Instruct students to copy the equation into their notebooks. Project the following question, and ask students to answer it in their notebooks. How does the chemical equation represent what happened in the Light s Out investigation in our previous lesson? The reactants baking soda and vinegar reacted and produced the products of carbon dioxide, water, and sodium acetate. (Students may use formulas.) A chemical change took place because a new substance formed. The products and reactants are different. It caused fizzing and bubbling which indicated production of a gas. Materials: beaker (250 ml,1 per group) water (100 ml per group) Epsom salts (MgSO 4 ) (5 g per group) non-sudsy household ammonia (NH 4 OH) (10 ml per group) stirrer (1 per group) safety goggles (1 per student) graduated cylinder (1 per group) balance (1 per group) timer (1 per group) 3. Instruct students to reference the Lights Out investigation in their notebooks, as well as the Chemistry Language Cards to assist in answering the question. 4. Using the same groups from the previous activity, distribute a copy of the Handout: Dropping Out. 5. Ask students to read the handout and prepare a page in their science notebooks. 6. Instruct students to create a before/after data table in their notebook to record observations/data throughout the investigation. They should include the substances, amounts, and characteristics/properties. Require students to Attachments: Handout: Dropping Out (1 per group) Teacher Resource: Dropping Out KEY Safety Notes: Have an MSDS available for household ammonia. Last Updated 04/24/13 page 7 of 49

8 answer all questions in complete sentences in their notebooks. 7. Discuss safety rules and procedures for working with chemicals with students. See the Safety Notes. 8. Distribute materials to each group. 9. Monitor and assist students during the activity and require them to clean up their lab stations. The mixture can be diluted with water and poured down the sink drain. 10. Facilitate a class discussion in which groups reflect on the following questions. Require participation from each group. Ask: Did a chemical change occur? Yes What is your evidence? A white solid formed and fell to the bottom of the beaker; a precipitate formed. How do the properties of the original substances compare to the new substance? Ammonia is a substance that dissolves in water; Epsom salts are crystals that dissolve in water. When mixed together, a white solid forms that will not dissolve in water. The white solid falls to the bottom of the beaker. 11. Instruct students to write a one paragraph summary of the investigation in their notebooks by using their data/observations and the answers to their questions. Encourage students to use the Chemistry Language Cards and Evidence of Chemical Change notes. Eye protection must be worn when working with chemicals. Never taste any substances in the lab. Remind students that wafting is the proper way to smell a substance and only when instructed. Be sure to point out the location of the eyewash stations. Check for students who may have asthma. Use a wellventilated area. Instructional Note: It may take time for the precipitate to form, so be prepared for an alternate task to keep students focused while waiting. Check For Understanding: The opening equation and student reflection can be entered in the science notebook or on a piece of paper for collection. You may need to give additional assistance to some students to guide their writing process. Unit: 04 Lesson: 01 Suggested Duration: 15 days Notebooks: Students complete the check for understanding reflection in their notebooks. Students also record data and observations, answer questions, and complete a summary about this activity in their notebooks. EXPLORE Temperature Suggested Day 6 1. Project the following chemical equation: MgSO 4 + 2NH 4 OH (NH 4 ) 2 SO 4 + Mg(OH) 2 magnesium sulfate (Epsom salt) + ammonium hydroxide (ammonia) yields ammonium sulfate + magnesium hydroxide 2. Instruct students to copy the equation into their notebooks. Project the following question, and ask students to answer it in their notebooks. How does the chemical equation represent what happened in the Dropping Out investigation in our previous lesson? The reactants magnesium sulfate and ammonium hydroxide reacted and produced the products of ammonium sulfate and magnesium hydroxide. (Students may use formulas.) A chemical change took place because a new substance formed. The products and reactants are different. A precipitate formed and fell to the bottom of the beaker. Materials: safety goggles (1 per student) plaster of Paris (236 g per group) water (118 ml per group) tape (roll per group) thermometer (1 per group) resealable plastic bag (quart-size, freezer weight, 1 per group) spoon (plastic, 1 per group) timer (1 per group) graduated cylinder (1 per group) balance (1 per group) 3. Instruct students to reference the Dropping Out investigation in their notebooks, as well as the Chemistry Language Cards to assist in answering the question. 4. Using the same groups from the previous activity, distribute a copy of the Handout: Changing Temperature. 5. Ask students to read the handout and prepare a page in their science notebooks. 6. Instruct students to create a before/after data table in their notebooks to record observations/data throughout the investigations. They should include the substances, amounts, temperatures, and characteristics/properties observed. Remind students to answer all questions in complete sentences in their Attachments: Handout: Changing Temperature (1 per group) Check For Understanding: The opening equation and student reflection can be entered in the science notebook or on a piece of paper for collection. You may need to give additional assistance to some students to guide their writing process. Last Updated 04/24/13 page 8 of 49

9 notebooks. 7. Discuss safety rules and procedures for working with chemicals with students (see Safety Notes). 8. Distribute materials to each group. 9. Monitor students during the activity, and require them to clean up their lab stations. 10. Remind students of the following: All plaster coated materials must be placed in the trash. DO NOT rinse any plaster down the sink. It will clog the drains. Use a damp paper towel to wipe the thermometer used to take the temperature of the dry plaster powder; place that towel in the trash. 11. Facilitate a class discussion in which groups reflect on the following questions. Require participation from each group. Did a chemical change occur? Yes What is your evidence? An increase in temperature and the material hardens into a new substance How do the properties of the original substances compare to the new substance? The dry plaster was soft and powdery; the water was clear liquid. After the two were mixed, there was an increase in temperature and they formed a hard new substance. 12. Instruct students to write a one paragraph summary of the investigation in their notebooks by using their data/observations and the answers to their questions. Encourage students to use the Chemistry Language Cards and Evidence of Chemical Change notes. Safety Notes: Have an MSDS available for Plaster of Paris. Eye protection must be worn when working with chemicals. Never taste any substances in the lab. Be sure to point out the location of the eyewash stations. Plaster dust can irritate mucus membranes. The plaster bag may become too warm to hold during the reaction. The bag should remain on the work surface until the temperature begins to cool. Notebooks: Students complete the check for understanding reflection in their notebooks. Students also record data and observations, answer questions, and complete a summary about this activity in their notebooks. Unit: 04 Lesson: 01 Suggested Duration: 15 days EXPLORE/EXPLAIN Color Suggested Day 7 7. Using the same groups from the previous activity, distribute a copy of the Handout: Color Switch. 2. Ask students to read the handout and prepare a page in their science notebooks. 3. Instruct students to create a before/after data table in their notebooks to record observations/data throughout the investigation. They should include the substances, amounts, and characteristics/properties. 4. Discuss safety rules and procedures for working with chemicals with students. (See the Safety Notes.) 5. Distribute materials to each group. 6. Monitor and assist students during the investigation. Remind them to clean up their lab stations. The mixture can be diluted with water and poured down the sink drain. 7. Facilitate a class discussion in which groups reflect on the following questions. Require participation from each group. Ask: Did a chemical change occur? Yes What is your evidence? The cabbage juice changed color when the powdery substance was added. How do the properties of the original substances compare to the new substance? The juice was dark blue. When the cream tartar was mixed in, it turned pink. When the detergent was mixed in, it turned green. 8. Instruct students to write a one paragraph summary of the investigation in their notebooks by using their data/observations and the answers to their questions. Encourage students to use the Chemistry Language Cards and Evidence of Chemical Change notes. Materials: safety goggles (1 per student) red cabbage leaves (2 per group) cups labeled ABC (clear, plastic, 3 per group) water (236 ml, room temperature, per group) resealable plastic bag (quart-size, 1 per group) cream of tartar (0.6 g per group) powdered laundry detergent (0.6 g per group) stirrers (2 per group) graduated cylinder (1 per group) balance (1 per group) Attachments: Handout: Color Switch (1 per group) Teacher Resource: Color Switch KEY Safety Notes: Have an MSDS available for Cream of Tartar and laundry detergent. Eye protection must be worn when working with chemicals. Remind students that materials should never be tasted in the laboratory. Instructional Notes: Last Updated 04/24/13 page 9 of 49

10 Unit: 04 Lesson: 01 Suggested Duration: 15 days Students may confuse bubbles from boiling a liquid with bubbles from gas production. Change of state is a physical change. Student may confuse the cabbage dying the water with a chemical reaction. Clarify that the cabbage dye behaves as food coloring which is a physical change. A color change is when a NEW and different color results from mixing two substances. Provide many examples and non-examples for comparison. Notebooks: Students need to record data and observations, answer questions and complete a summary about this activity in their notebooks. EXPLAIN Compare/Contrast Chemical/Physical Changes Suggested Day 8 1. Instruct students to work with a partner and use the Chemical Language Cards to add the terms, definitions, and some examples of chemical change and physical change to their notebooks. 2. Project the Teacher Resource: Evidence of Chemical Change used earlier in the lesson, and direct students back to this page in their notebook as a reference. Students were introduced to these concepts in Grade Ask students to share their examples of chemical and physical changes with the large group. Clarify any misconceptions, and instruct students to add to their examples to their notebooks and make any corrections during the process. 4. Say: Physical change examples: cutting, change of state, dissolving, change in size, mass, volume, etc. Chemical change examples: rusting, burning, baking soda plus vinegar, cooking (new substances form), fireworks, etc. During the last four days, you have conducted four investigations and recorded data and answered questions about the activities in your notebooks. You will reference these pages as well as the notes on Evidence of Chemical Change to complete the next task. Attachments: Teacher Resource: Evidence of Chemical Change (1 for projection, from previous activity) Handout: Signs of a Chemical Reaction (1 per student) Teacher Resource: Signs of a Chemical Reaction KEY Check For Understanding: Consider using an exit ticket strategy to check student understanding of physical and chemical changes. Notebooks: Students should record terms and notes in their notebooks. Students may also record the check for understanding in their notebooks. Students need to affix the handout in their notebooks. 5. Distribute the Handout: Signs of a Chemical Reaction to each student. 6. Instruct students to look through their notebooks to check for signs of a chemical change. 7. Monitor student responses as students complete the handout. Clarify as necessary. 8. End the lesson by using an exit ticket strategy. Ask: What are some indicators that are evidence that a new substance has been formed during a chemical reaction? Students should be able Last Updated 04/24/13 page 10 of 49

11 to recall the evidence they just recorded from the lab activities. Color, gas, light, temperature, precipitate Unit: 04 Lesson: 01 Suggested Duration: 15 days 9. Instruct students to compare/contrast physical and chemical changes. You may wish to give students the option of completing the task in a chart or paragraph format. EXPLORE/EXPLAIN Decoding Chemical Formulas Suggested Days 8 (continued), 9, and Instruct students to refer back to their Components of Chemical Equations Part I page in their notebooks. 2. Project the Teacher Resource: Components of Chemical Equations Part II. Instruct students to use the Chemistry Language Cards to add more labels to the page in their notebooks. They should add symbol, subscript, coefficient, chemical equation, and chemical formula. 3. Project the Teacher Resource: Components of Chemical Equations Part II KEY for students to check and correct their answers. 4. As a review, instruct students to collaboratively answer the following questions in their notebooks and be prepared to share out with the large group. Ask: (Students may use notes and Chemistry Language Cards.) What is a chemical symbol? Give an example. A chemical symbol is one or two letters used to represent an element - Na; H; O; C, etc. In a chemical formula such as NaHCO 3, how can we tell one element from another? Every element symbol begins with a capital letter. What is a subscript? Give an example. A subscript is a small number to the right of a symbol that is written below the normal line of letters to show how many atoms of an element are present in a substance. No subscript means there is only one atom present. H 2 O two atoms of hydrogen; one atom of oxygen. What is a coefficient? Give an example. A coefficient is a number written in front of a chemical formula to show how many molecules of that substance are present - 4H 2 O; four molecules of H 2 O are present. What is a chemical formula? Give an example. A chemical formula is a combination of symbols and numbers that represent the number and types of elements (atoms) present in a compound. NaHCO 3 ; There is one atom of sodium, one atom of hydrogen, one atom of carbon, and three atoms of oxygen. What is a chemical equation? Give an example. A chemical equation uses chemical formulas and symbols to represent what happens in a chemical reaction. Materials: resealable plastic bags of blocks (centigram/cc blocks, various colors, see Advance Preparation, 1 set per group) tape or glue (per pair) colored markers or pencils (per pair) Attachments: Teacher Resource: Components of Chemical Equations Part II (1 for projection) Teacher Resource: Components of Chemical Equations Part II KEY (for projection) Handout: Decoding Chemical Formulas (1 per student) Teacher Resource: Decoding Chemical Formulas KEY (1 for projection) Teacher Resource: Modeling Chemical Formulas (1 for projection) Teacher Resource: Modeling Chemical Formulas KEY Handout: Counting Atoms (1 per student) Teacher Resource: Counting Atoms KEY Handout: What s the Count? (1 per student) Teacher Resource: What s the Count? KEY Instructional Notes: Use a strategy that requires students to first answer these questions by talking to one another prior to recording answers in their notebooks and sharing out large group. MgSO 4 + 2NH 4 OH (NH 4 ) 2 SO 4 + Mg(OH) 2 5. Say: When the reactants are mixed together, they yield (produce) the product which is a new substance with different properties from the reactants. Now that we know all of the components of a chemical equation, let s practice decoding chemical formulas. 6. Distribute and project the Handout: Decoding Chemical Formulas to each student. Model how to decode a formula for students, and then assist them in completing one together. Instruct students to complete the handout and then affix it to their notebooks. 7. Distribute bags of colored blocks from the Teacher Resource: Modeling Chemical Formulas (see Advance Preparation) so students can practice constructing models. 8. Instruct students to practice building models of the compounds they just finished decoding. Project the Teacher Resource: Modeling Chemical Formulas. 9. Instruct students to record formulas and notes in their notebooks and follow along while collaboratively constructing models. Model for students. Students The order in which model atoms connect (bond) to form compounds is not addressed in middle school. Accept any arrangement of atoms in the compound. The focus in middle school is accurately counting atoms. Check For Understanding: Use the Handout: What s the Count? and the following question as a check for understanding. Notebooks: Students will add labels to the Components of Chemical Equations and answer questions in their notebooks. Students will complete Handout: Decoding Chemical Formulas and affix it to their notebooks. Last Updated 04/24/13 page 11 of 49

12 should use colored pencils or markers to draw the models they construct. 10. Distribute the Handout: Counting Atoms to each student. Answer any questions they may have about the instructions. 11. Monitor students and assist students as they complete the handout. 12. Distribute bags of plastic blocks to each station (see Advance Preparation). 13. Instruct students to work collaboratively in stations to construct models of the chemical formulas on the Handout: Counting Atoms. Students should draw their models in their notebooks and use colored pencils or markers that correspond to the key. Students will record notes/drawings and answer questions from the Teacher Resource: Modeling Chemical Formulas. Students will record and color drawings of chemical formulas in their notebooks. Unit: 04 Lesson: 01 Suggested Duration: 15 days Check for Understanding may be recorded in notebooks. 14. Monitor and assist student groups as needed. 15. Distribute Handout: What s the Count? to each student. Ask: How are chemical formulas used to determine the number of atoms of each element present in a compound? The subscripts represent how many atoms of each element are present, and the coefficients represent how many molecules of each compound. The coefficients are multiplied by the subscripts. No subscript or coefficient means there is only on atom or molecule present, respectively. EXPLORE/EXPLAIN Lose Anything? Suggested Days 11, 12, and Distribute the Handout: Lose Anything? to each student. 2. Instruct students to work through the activity with a partner while recording information on their own handout. 3. Monitor students and make clarifications during the activity. 4. Instruct students to use the Chemistry Language Cards to add the term and definition of the law of conservation of mass to their notebooks. 5. Discuss with students the results and answers to the questions on the Handout: Lose Anything?, and reinforce the concept that the total number of atoms and the kinds of atoms do not change during chemical reactions. This is because matter is not created or destroyed, only rearranged. 6. In addition, discuss this activity in terms of a model. Instruct students to answer the questions in their notebooks. Allow students to discuss with partner(s) first. Ask: What do the coins represent? The coins represent atoms and the different combinations they can make. How does this activity model the law of conservation of mass? The number and value of atoms/coins remains constant. They are only rearranged. What are the limitations of this model? The model does not show the reactants or products involved in a chemical reaction; there is not a chemical equation or a chemical change. Students may offer other answers such as: size, too random arrangement of atoms, mass was not actually measured, etc. Accept all reasonable answers. 7. If time allows, you may wish to have students complete the activity in the Optional Handout: It s the Law. 8. Prior to the activity, ask students to read the handout and prepare a page in their science notebooks. Instruct students to answer all questions in their notebooks. 9. Allow students time to complete the activity. Monitor students during the activity, and remind them to clean up their lab stations. Materials may be diluted with water and disposed of down the sink. 10. Ask students to discuss the results of the activity and their answers to the questions. Materials: coins or play money (various denominations, 24 per group) paper lunch bag (1 per group) periodic table (1 per group, see Resources and References section) safety goggles (1 per student, for Optional Handout: It s the Law) plastic water or soda bottle (1 per group, for Optional Handout: It s the Law) balloon (1 per group, for Optional Handout: It s the Law) vinegar (40 ml per group, baking soda (15 g, for Optional Handout: It s the Law) triple beam balance, for Optional Handout: It s the Law) funnel (1 per group, for Optional Handout: It s the Law) tape (masking,1 roll per group, for Optional Handout: It s the Law) graduated cylinder (1 per group, for Optional Handout: It s the Law) blocks (various colors per group, for Optional Handout: It s the Law) colored pencils (per group, for Optional Handout: It s the Law) Attachments: Handout: Lose Anything? (1 per student) Teacher Resource: Lose Anything? KEY Optional Handout: It s the Law (1 per group) Optional Teacher Resource: It s the Law KEY Teacher Resource: Balanced Practice (1 for projection) Teacher Resource: Balanced Practice KEY Last Updated 04/24/13 page 12 of 49

13 11. Reinforce the concept that the total number of atoms and kinds of atoms do not change during chemical reactions because matter is not created or destroyed; only rearranged. 12. Say: In a chemical equation, when the elements and number of atoms in the reactants and elements and the number of atoms in the products are equal, we call it a Balanced Equation. Balanced equations illustrate or prove the law of conservation of mass. We are going to look at some chemical equations and determine if they are balanced. The only requirement is knowing how to count atoms in a chemical formula. 13. Project the Teacher Resource: Balanced Practice. Model for students how to check to see if an equation is balanced, and then assist the class in completing examples together. 14. Instruct students to copy the practice equations in their science notebooks as you all work through them together. 15. Ask students to discuss the answers to the following questions with a partner and then to record it in their notebooks. When students are finished, ask for a few students to share their answers with the class. What is a balanced equation? A chemical equation in which the elements and number of atoms in the reactants are equal to the elements and the number of atoms in the products How do balanced chemical equations relate to the law of conservation of mass? When a chemical equation is balanced, the elements and number of atoms present in the reactants are equal to the elements, and the number of atoms present in the products are equal. This proves the law of conservation of mass because matter was not created or destroyed, only rearranged. Do unbalanced equations demonstrate the law of conservation of mass? Why or Why not? Unbalanced equations do not demonstrate the law of conservation of mass. The numbers of atoms present in the reactants is not equal to the numbers of atoms present in the products. Therefore, mass is not conserved. 16. Distribute the Handout: Balanced? to each student, and answer any questions they may have regarding the instructions. Encourage students to draw diagrams or to show their math if it assists them. 17. Make manipulatives available to students who may need a more concrete approach. 18. Monitor and assist students, clarifying as needed. 19. As students finish, instruct them to select one or more of the chemical equations listed on the Handout: Balanced? and construct and draw a model that represents their findings. Remind them to include a color key. 20. Instruct students to write a paragraph explaining the following: how to determine if a chemical equation is balanced or not the relationship between a balanced chemical equation and the law of conservation of mass. Handout: Balanced? (1 per student) Teacher Resource: Balanced? KEY Safety Notes: Have an MSDS available for the vinegar and baking powder. Eye protection must be worn when working with chemicals. Never taste any substances in the lab. Be sure to point out the location of the eyewash stations. Instructional Notes: Allow students the opportunity to discuss answers prior to recording in notebooks and having a large group oral discussion. During practice, provide students ample opportunity to collaborate and verbalize their thought processes. If you choose opt out of Handout: It s the Law, this will provide one additional day for student work on the Performance Indicator. Check For Understanding: Students write a paragraph explaining the following: how to determine if a chemical equation is balanced or not the relationship between a balanced chemical equation and the law of conservation of mass. Misconception: Students may think that the law of conservation of mass does not apply to atoms. Notebooks: Unit: 04 Lesson: 01 Suggested Duration: 15 days Students should record notes regarding the law of conservation of mass and will answer discussion questions in their notebooks. The Check for Understanding reflective paragraph may also be written in notebooks. ELABORATE Review Stations Suggested Day Prepare stations prior to class (see Advance Preparation). 2. Project the Performance Indicator see Day 15. Instruct student groups to rotate through stations to review and prepare for the requirements of the Performance Indicator. Materials: bags of blocks (for Station 3, see Advance Preparation) Last Updated 04/24/13 page 13 of 49