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Formulas, Equations, and the Conservation of Mass
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Warm Up
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So What? Unit 4: Chemical Equations Turn to your next blank page and title it So What? Create Graph Observations Before Mixing Solid Observations Before Mixing Liquid Observations After Mixing A 1) 2) 3) 1) 2) 3) 1) 2) 3) B 1) 2) 3) 1) 2) 3) 1) 2) 3)
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So What? 1. Observe and describe the substances in your science notebook before beginning the investigation. Be sure to indicate which is “A” and which is “B”. 2. The bags are labeled “A” and “B”. Do not mix the two bags. 3. Add the 10 mL of “Liquid A” to the bag labeled “A”, and seal the bag quickly. Gently knead the bag. Record your observations. 4. Add the 10 mL of “Liquid B” to the bag labeled “B”, and seal bag quickly. Gently knead the bag. Record observations. 5. Observe and describe the substances after the mixing occurs; record what you see and feel after steps 3 and 4.
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So What? Beneath your graph write and answer these questions 1. What did you observe? 2. What do you think caused the difference in the bags? Make sure you provide supporting evidence for your explanation.
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So What? We will spend the next few weeks exploring, learning, understanding, and explaining exactly what happened and did not happen in the bags today. You will come back to this investigation multiple times throughout the unit, and you 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.
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Download App Molecule Rush (Black Green Circles) Chemical Reaction Lite (Blue Green Flask) Chemistry Challenge (Picture of Cat)
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Warm Up
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Seat Change Test Review
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Using Chemistry Language With your shoulder partner match the correct word with the correct definition.
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Using Chemistry Language Take a picture of all the terms correctly matched and turn into ebackpack
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Using Chemistry Language Label your next blank page “Using Chemistry Language” REMEMBER GO TO THE LAB GRAPH FROM YESTERDAY AND MAKE A NEW PAGE Write the following equations on the page just like you see it Bag “A” NaHCO 3 + H 2 O NaHCO 3 + H 2 O Bag “B” NaHCO 3 + HC 2 H 3 O 2 CO 2 + H 2 O + NaC 2 H 3 O 2
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Using Chemistry Language Chemical Equations are a shorthand way that scientist use to represent what takes place in a chemical reaction. Chemical equations consist of many components (parts). Now I want you to try and label the parts of the chemical equation you just wrote. Do the best you can. Project Engage Investigation Components of Chemical Equations Part 1
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Using Chemistry Language On the same NEXT page create this chart Chemical Equations Bag A Bag B
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Warm Up
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Fan–N-Pick Million Dollar Question How do the chemical equations for Bag "A" and "B" explain what did or did not happen in our investigation?
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Using Chemistry Language 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? Bag “A”-No; Bag “B” – Yes: gas production, bubbles, temperature change
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Gas Production Title your next blank page “Gas Production” Write the following memory device Country (city) = Color change Girls (guys) = Gas production Love = Light production Their = Temperature change Phones = Precipitate formation
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Gas Production Title your next blank page “Light Out Lab” Record the following chart and questions on the page Observations (3 observations per box) Baking Soda Vinegar Mixed What happened to the flame? Why? What do you notice about the temperature? How are the properties of the original substance different than the properties of the resulting product?
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Warm Up
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Yesterday Did a chemical change occur? Yes What is your evidence? Fizzing, bubbling, gas production, odor change, temperature change, new substance 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
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Precipitate Title the next blank page Precipitate Copy the equation into their notebooks. 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 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.
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Dropping Out Lab What is forming and falling at the bottom of the jar? What is the scientific name for it? How do the properties of the original substances compare to the new substance? Observations (3 observations per box) Amounts Epsom Salt Ammonia Mixed after 1 minute Mixed after 5 minute Mixed after 10 minute Page title
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Precipiate 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
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Temperature Title the next blank page Temperature Copy the equation into your notebooks. MgSO 4 + 2NH 4 OH (NH 4 ) 2 SO 4 + Mg(OH) 2 magnesium sulfate + ammonium hydroxide yields ammonium sulfate + magnesium hydroxide (Epsom salt) (ammonia) 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. 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.
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Getting Warmer Observations (1 per box)Temperature Plaster of Paris Initial 2 Minutes 4 Minutes 6 Minutes 8 Minutes 10 Minutes 12 Minutes 14 Minutes 16 Minutes 18 Minutes 20 Minutes Page title
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Getting Warmer Page title Record and answer these questions at the bottom of your page 1.What patterns did you see? 2.How are the properties of the original substance different than the properties of the resulting product?
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Friday 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.
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Color Switch How did cups A and B compare to the control cup C? Observations (3 observations) Observations After Mixing (3) Cabbage A Cream of Tarter B Laundry Detergent C Control Page title
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Warm Up
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Think Back to Monday 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.
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CGLTP Are bubbles from boiling water a sign of a chemical change? NO, it is a physical change When the cabbage leaves dyed the water, what kind of change was that? physical change A Color change is when a new color results from mixing two substances
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Chemical and Physical Changes Country (city) = Color change Girls (guys) = Gas production Love = Light production Their = Temperature change Phones = Precipitate formation With your table group think of 3 examples of a physical change and 3 examples of a chemical change Write them in uPad be prepared to share in 5 MINUTES
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Chemical and Physical Changes 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
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Video Watch video http://studyjams.scholastic.com/studyjams/jams/scie nce/matter/changes-of-matter.htm http://studyjams.scholastic.com/studyjams/jams/scie nce/matter/changes-of-matter.htm
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Chemical and Physical Changes 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.
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Chemical and Physical Changes Open the Inspiration Maps app on your iPad (if you don’t have it download it right now!) Choose the Thinking: Compare and Contrast Map For Subject A write Physical Changes For Subject B write Chemical Changes Your map must include 5 similarities 10 differences (total) 4 labs (such as where would the Color lab fit) 5 words from the word bank 5 pictures Hand drawn or from the internet Word Bank 1)Symbols 2)Chemical Formulas 3)Subscripts 4)Chemical Reaction 5)Chemical Equation 6)Coefficient 7)Reactant 8)Product 9)Yields 10)Compound 11)Law of Conservation of Mass 12)Precipitate
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Homework Complete the Signs of a Chemical Reaction in ebackpack Due tomorrow
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Warm Up
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Decoding Chemical Formulas Turn to the next blank page in uPad and label it Components of a Chemical Equation Then write the following equation 2Na 2 O 2 + 2H 2 0 4NaOH + O 2
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Recap 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
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Recap 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 to represent what happens in a chemical reaction. MgSO 4 + 2NH 4 OH (NH 4 ) 2 SO 4 + Mg(OH) 2 When the reactants are mixed together, they yield (produce) the product which is a new substance with different properties from the reactants.
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Chemical Equation Station You will rotate with your group through the 3 stations and complete the handout as you go Work as a group Pay attention to what station you are at Use the blocks and counters
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What’s the Count? 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.
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Warm Up
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Aps Fun with Chemistry Glow Fizz Chemistry Kit
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Lose Anything? Complete lab and handout with your SHOULDER PARTNER
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Law of Conservation of Mass Title the next blank page Law of Conservation of Mass Write the following definition Matter is not created or destroyed, only changed. The number of atoms in the reactants must be equal to the number of atoms in the product. Add a picture at the bottom of the page to help you remember the definition
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Lose Anything Discussion If the coins represented different types of atoms, what can you infer about this model being used to explain a chemical reaction and chemical equation. So the total number of atoms and the kinds of atoms do not change during chemical reactions. Why? Because matter is not created or destroyed, only rearranged.
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Questions With your shoulder partner write the answer to the questions on a note card and the note card is your “ticket” out the door. What do the coins represent? How does this activity model the law of conservation of mass? What are the limitations of this model?
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It’s the Law Open the Lab from yesterday Listen to Directions
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It’s the Law 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. Copy the practice equation on the next blank page titled Balance Practice
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Balanced Practice Switch to Mimio Homework Due Thursday
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Warm Up
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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.
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Review Stations 7 minutes per station Paper and station must be complete
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Warm Up
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Chemical Equation Manual Listen to Directions
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Warm Up Study your spiral Write “Test” on your warm up log Turn in Your Warm Up log by the Sink After the Test STAY QUEIT You may read, work on homework, or log on to study island If we have time I will check your grades after the test
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After the Test STAY QUEIT You may read, work on homework, or log on to study island If we have time I will check your grades after the test
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Using Chemistry Language Title the next blank page “Chemical Language Vocabulary”
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Using Chemistry Language Using the White Boards we will answer the following questions What was alike/different in the two equations? They both have the same component parts; NaHCO 3 was a reactant in both equations. The products and reactants were the same 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, the reactants and products were the same. 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.
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Using Chemistry Language Using the White Boards we will answer the following questions 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? The reactants were combined to form a new substance. Therefore, they are differently arranged. What does this mean? A chemical reaction/change occurred, and a new substance was formed.
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