Chemical Reactions Unit miss E. Mac's Class

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Chemical Reactions Unit Overview 3 Chapter 1: Properties and Atoms Chapter Overview 4 Lesson 1.2: A Water Mystery in Westfield 5 Warm-Up 6 Investigating a Mysterious Substance 7 Observing Substances 8–9 Lesson 1.3: Analyzing Substances and Properties 10 Warm-Up 11 Investigating Substances 12–13 Evaluating Evidence 14. Grade 7 Science, Unit 3 Chemical Reactions Overview Unit abstract Upon completion of this unit of study, students will be able to provide molecular-level accounts of states of matters and changes between states, of how chemical reactions involve regrouping of atoms to form new substances, and of how atoms rearrange during chemical reactions. This Unit, Chemical Reactions is a skills course and requires a lot of concentration. If you study well, you will learn a lot. I hope that you will find this unit an enjoyable unit to study as well. This Unit is based on the Lower Secondary Schools Science Curriculum. In this Unit, there are five topics which comprises 20 Lessons.

The study of chemistry invariably requires a study of chemical reactions. This takes up the bulk of first year chemistry classes and will actually be divided over several units:

  1. Chemical Reactions (this unit)
  2. Stoichiometry (next unit)
  3. Reaction Energy (later units)
  4. Reaction Rates and Equilibria (later units)

Chemical Changes- The second grade students will investigate some chemical changes and reactions and should be able to identify at least four characteristics that indicate a chemical change. Chemical Changes - To learn that the formation of gas bubbles is an indication of a chemical change.

This unit, which is the first in that list, will center around building your mastery on

  1. Chemical Changes
  2. Balancing chemical reactions
  3. Writing reactions from word prompts
  4. Identifying types of reactions
  5. Predicting the outcomes of reactions
    1. Predicting the outcomes of Double Displacement Reactions
    2. Predicting the outcomes of Single Displacement Reactions
    3. Writing Net Ionic Equations of Double Displacement and Single Displacement Reactions
Class

While this may be a long unit, this is going to be a unit that builds as we go, with each subsequent skill in the above list building on prior skills. Because of that, we’re going to take a more direct approach to the unit and you will work to learn, then practice the skills at each step of the way.

Physical and Chemical Changes

Chemical reactions occur in nature, in the lab, at home and in our bodies. The fundamental principle of a chemical reaction is that a substance changes into a completely different substance as atoms rearrange into different structures and molecules. This is different than a physical change, where apparent properties might change, but not in a fundamental way. Read this article on the difference.

Unit miss

It’s important to note that regardless of how much a chemical reaction looks like a mathematical equation, it’s not. It is a process of rearrangement. Consider the combustion of methane below.

In this reaction, the atoms in a methane molecule and oxygen molecules rearrange themselves to become carbon dioxide and water molecules. The left doesn’t equal the right, the left becomes the right.

When this happens, the substances change: Methane and oxygen no longer exist, carbon dioxide and water do exist and the properties of the materials become new properties!

It can be hard to tell when a chemical change has occurred because we cannot see the individual particles or atoms, but the change in properties is the biggest hint. Therefore we classify several evidences of reactions. Read here on the five evidences of chemical change. Later on in this unit, you will put these observations to the test.

Writing chemical reactions requires that we understand one basic fundamental principle: The Law of Conservation of Mass. This means that matter or mass can never be created or destroyed through any process (although we did learn in the Nuclear Unit that it can be converted to and from energy, this fine detail doesn’t necessarily apply to what we’re learning here.) By extension, this also means that atoms are never gained or lost in chemical reactions.

  • Watch the video here to learn about the basics of chemical reactions as well as terminology used when writing chemical reactions. This brief rundown also shows the parts of a reaction.
  • There are no worksheets in this section, but you should take ample notes on the readings and videos.
  • Take this quiz(4 EP) to check your understanding before moving forward.

Balancing Chemical Reactions

Because of the law of conservation of mass (LoCoM), chemical equations going from reactants to products can never lose or gain any atoms that are unaccounted for on both sides. Both sides of the equation must “balance” or have the same mass, or have the same number of atoms of each type. But you cannot change what the substances are by altering ratios. Instead we use coefficients to balance equations. Coefficients like in algebra “2x” means “two of x,” so in a similar fashion writing 2H2O means “two H2O molecules,” or because equations are seen as ratios, it could also be read as “two moles of H2O molecules.” This would mean that while there are two molecules of H2O, there are, because of the coefficient, four H atoms and 2 O atoms total.

Chemical Reactions Unit  Miss E. Mac's Class Of

When balancing chemical reactions, there are different methods of accounting and you may have to go back-and-forth, but if formulas are written properly, there is always a way to balance the equation.

  • Watch this video about balancing equations. PhET has a practice with balancing chemical equations here. Use this worksheet(10 AP) to guide yourself through the activity. Also try this practice set.
  • This activity(10 AP) can also help get you in the “LoCoM mindset” but you’ll need a molecular model kit in order to do it.
  • This practice worksheet(10 RP) (KEY) will help you master the concept of equation balancing.
  • This is additional practice(10 RP) (KEY) on equation balancing.
  • (Still feeling uncertain? Visit Mr. Carman’s blog where he has an auto-grading balancing quiz)

Turn in all 4 assignments for 20 total Research Points and 20 total Activity Points.

  • Take this quiz(5 EP) on balancing reactions before moving forward in the unit.
  • If you didn’t do well on the quiz, you can try this POGIL(15 RP, optional) to try to bolster your mastery.

Writing Chemical Reactions

When writing chemical reactions, you’ll be expected to know chemical formulas from names, be able to make reasoned assumptions about state of matter (s, l, g, aq) and then properly arrange the compounds in the right order (reactants -> products) and then finally balance the equation. Being able to do this involves some practice, but once you get used to it, can be helpful in being fluent in chemistry.

  • Watch this video about writing chemical reactions.
  • This practice worksheet(20 RP) (KEY) can help you master writing chemical reactions. There’s a lot of practice there, so completing half of them is sufficient. Try all the odds or all the evens. If you need to return for additional practice, try the rest.
  • Instead of a quiz for this part of the unit, go over the answer key of the practice worksheet to prepare for the midpoint quiz.

Turn in 1 assignment for 20 total Research Points.

Midpoint Quiz

After these sections, there is a written quiz on chemical reactions that you will need to take before moving forward in the unit. This paper quiz is worth 20 Evaluation Points and will cover evidence of chemical reactions and writing and balancing chemical reactions. Review your previous practice quizzes and work to prepare as there is no practice quiz for this.

Types of Reactions

There are many different ways to classify reactions, but we generally recognize five general reaction forms. Reaction forms are helpful in predicting the outcomes of reactions and can assist in conversations about reactivity.

  • This video goes over the five different types of reactions. Also ChemFiesta has a helpful rundown, although she classifies six reactions (Acid-Base Neutralizations fall under the category of Double Replacement)
  • This would also be a great time to do a lab on types of reactions! Once you look at the video rundown, you and two others (max lab groups are 3) can do this lab on types of reactions. It’s actually a series of mini-labs. This is the guiding document here(20 AP).
  • This practice worksheet(10 RP) covers classifying reactions.
  • This practice worksheet(20 RP) covers predicting the outcomes of reactions.

Double and Single Displacement reactions fall under the category of being predictable, but other factors determine the actual result of a reaction: just because you can write it, doesn’t mean it happens. When trying to predict if a reaction will occur, we use solubility rules(keep for reference) for double displacement reactions and for single displacement reactions, we try to determine where they are on the activity series(keep for reference).

  • Watch this video on double replacement reactions and how to predict the outcome of their reactions. This video goes over predicting single replacement reactions.
  • This practice covers how to determine the outcomes of double displacement(10 RP) and single displacement reactions (this practice worksheet(10 RP) goes over single displacement).
  • This lab(20 AP) covers the concept of precipitation of double displacement reactions.

Turn in four practice worksheets (50 Research Points) and 2 labs (40 Action Points).

  • There is a brief written quiz (18 EP) on classifying reactions and predicting the outcomes of single and double replacement reactions. Before you take this quiz, take this practice quiz(4 EP).

SURPRISE REDOX ADDENDUM!

Chemical Reactions Unit miss E. MacChemical reactions unit  miss e. mac

OMG I totally got you! You thought you’d get out of this unit without having to do redox!

“What is redox?” you might ask. Redox is a term short for Reduction-Oxidation, which are both concepts that can confound students. Reduction and Oxidation are partnered actions in many chemical reactions, one part (reduction) talks of the gain of electrons by some species in the reaction, while the other part (oxidation) talks of the loss of electrons by some species. And just like if I lost twenty dollars on the ground, and you found twenty dollars, chances are – its the same twenty. In this case the reduction/oxidation pair tells the story of where electrons are going in a reaction.

In order to get a full understanding of how to handle redox analysis, we will first have to look at how to determine oxidation numbers. Oxidation is a level of “electron”-richness where the number indicates how many electrons an element has given what kind of a state/compound it is in. Its very much like ionic charge. So much so that that’s one of the rules:

Rules of oxidation numbers:

  1. Anything in its elemental state is 0. [this means sodium (Na) or oxygen (O2)]
  2. The charge of an ion is its oxidation state. [Na+ has a +1 oxidation state]
  3. All O.N.’s in a polyatomic ion or molecule have to add up to the charge on the ion/molecule.
  4. Oxygen in a compound is always -2 [unless its in a peroxide (O22-) which is rare, but happens]
  5. Hydrogen in a compound is always +1 [unless its hydride. See Rule #2]
  6. If you’re unsure between two elements, the more electronegative element gets its “column charge” [i.e. between N and F, F would decide by being -1. Between N and C, N would decide by being -3.]
  7. Most other O.N.’s can be deduced from these 6 rules.
  • Try this list(10 RP) to see if you can correctly identify the oxidation numbers of the elements in the following species.
  • Check out this article on how oxidation and reduction works in reactions. This video (and this one!) can also reinforce redox concepts.
  • Try this worksheet(15 RP) to see if you can work out redox pair reactions. This worksheet(15 RP) offers additional practice on half-reactions.
  • If it helps, Hank Green also gives an overview of redox reactions in this Crash Course video.

Redox reactions often occur in acidic or basic solutions. The balancing of these reactions can be complex. This video goes over the process of balancing redox reactions (take note of the steps!!) and this guide should help in the steps. Then, complete this worksheet on balancing redox reactions in acidic solutions(15 RP).

Chemical Reactions Unit miss E. Mac

Additional Practice on Redox.

Chemical Reactions Unit  Miss E. Mac's Classics

Take this practice quiz(6 EP) on predicting the outcomes of reactions and redox reactions.

This was a long unit, but by now you should be proficient in writing, balancing and predicting the outcomes of many different types of reactions. Take this review to practice additionally and then try this practice quiz to assess your general understanding of the concepts in this unit. Being successful at this will ensure your success on the written test for Chemical Reactions.

Atomic Structure WorkbookElements, Compounds, Mixtures Theme
Chemistry Web SitesLesson Plans On Matter

Chemical Reaction Lesson Plans

  1. Acids/Bases- The student will be able to: 1) distinguish between the differences of acids/bases, 2) demonstrate how to test for acids and bases, and 3) communicate the significance of testing for acids and bases.
  2. Acids And Bases- Determine the acidity of various liquids.
  3. Acid(s)-Base(s) Detective- Learn to prepare universal indicator at home.
  4. Acids, Bases, and Indicators- This is a multileveled approach to learning some of the common characteristics of acidic and basic solutions and use of some of the common indicators.
  5. Acid Rain Environment Pollution- Demonstrate how to use a pH indicator.
  1. Activation Energy- The student will construct and interpret an energy diagram showing the progress of an exothermic reaction.
  2. An Introduction to Acids and Bases- Students will classify household liquids as bases or acids by using cabbage-juice paper and then litmus paper.
  3. Bleach Chemical Reactions- Purpose is to shows what happens when Bleach comes in contact with various cloth fibers, chemical colors, nature and synthetics.
  4. Bubble Festival- My students will discover and learn some scientific and mathematical principles while having fun with bubbles.
  5. Calorimetry- To develop an understanding of the fundamentals of calorimetry. That the students will learn how to manipulate and set up the equipment and the development of increasing and decreasing amounts of heat.
  6. Calories- The students will be able to plan a balanced meal for a day including breakfast, lunch and dinner.
  7. Can Acids And Bases Remedy The Body?- Determine how an understanding of acids and bases relates to their personal bodies.
  8. Chemical Change and Physical Change- To learn that a chemical reaction occurs when two reactants combine to form a new product.
  9. Chemical Changes- The students in grades 3-8 will be able to explore some properties of Chemical Changes.
  10. Chemical Changes- The second grade students will investigate some chemical changes and reactions and should be able to identify at least four characteristics that indicate a chemical change.
  11. Chemical Changes- To learn that the formation of gas bubbles is an indication of a chemical change.
  12. Chemical Equilibrium- Distinguish between reactions that go to completion and those that are reversible.
  13. Chemical Reactions - The topics I am going to cover in this lesson are atoms and chemical reactions.
  14. Chemical Reaction Rates- To learn phenomenologically some of the factors which affect the rates of chemical reactions.
  15. Chemical Reactions With Vinegar- To determine whether vinegar creates a chemical reaction.
  16. Chemistry is pHun- The main objectives of this mini-teach are to familiarize uppergrade students with the concept of pH, to teach students how to use litmus and pH paper to determine pH and to make students aware of natural indicators.
  17. Chromatography- Acquaint students with chromatography as a technique useful in separating mixtures.
  18. Cleaning Of A Metal- Students will determine what cleans this particular metal.
  19. Coke Soda, Hot VS. Cold- Students will learn a physical chemical reaction in two bottled coke soda, hot vs. cold pop. Students will measure the beginning and the ending of bubbles.
  20. Combining Elements to Form a Compound- The student will understand that when two elements are combined, they form a compound.
  21. Cooperative Learning Experience Through the Flipping Lid Demo- To demonstrate a need for safety in the science lab through a series of learning experiences.
  22. Electrolytic Titration- Electrical conductivity depends on the presence of ions in a solution.
  23. Electrochemistry- Students understand that electricity causes chemical reactions and chemical reactions can cause electricity.
  24. Empirical Formulas- Upon the completion of this lesson when asked 95% of the students will orally, on written test or demonstrate how to find an empirical formula.
  25. Energy and Changes of State- Students will: 1) gain an understanding about energy and changes of state; 2) read a thermometer; 3) collect and record data; 4) construct a graph; and 5) interpret graphed data.
  26. Equilibrium: What is it?- To have the students define the term �equilibrium� through mechanical, chemical, and physical examples of equilibria.
  27. Evaporation and Temperature Change- The students will compare how much heat is required for various substances to evaporate by measuring how much the surrounding temperature decreases.
  28. Exothermic And Endothermic Reactions- Students are to observe several exothermic and endothermic reactions.
  29. Getting Down to Basics (and Acidics)- Students will identify and define the concepts of acid, base, indicator and neutralization.
  30. Household Acids and Bases- The learners will be able to determine whether a substance dissolved in water will form an acid, a base or a neutral solution.
  31. How to Make Invisible Ink- The students in grades four - six will learn how to make two types of invisible ink and write a message with each type of ink.
  32. Indicators For Acids And Bases- Make cabbage water as an indicator and see the color it turns when acids and bases are mixed in it.
  33. Introductory Lesson on How pH Levels Are Determined- To make students aware of the importance of pH levels in their day to day lives.
  34. Investigating Chemical Changes - Students will be able to investigate how several materials combine, and look for evidence of a chemical change.
  35. Measuring the Heat Energy of a Chemical Change- To compare the heat conducting properties of water and paper by boiling water.
  36. Mystical Membrane- Students will be able to explain Osmosis and Diffusion.
  37. Osmosis- To teach concepts of chemical and physical changes, and the difference between osmosis and diffusion in the movement of molecules in a liquid environment.
  38. Over-the-Counter Antacids- Based on this information and on a knowledge of side effects, the student consumer will be able to decide which, if any, antacid to choose.
  39. Oxidation and Reduction- To describe the procedures used and the reactions occurring during the electroplating of a metal.
  40. Oxidation: How Can It Be Proved?- Students will participate in some phenomenological activities illustrating oxidation.
  41. pH Neutralization For Pollution Control- Acid and Base Recognition.
  42. POLYMERS - GREAAAAAAT BIIIIIIG MOLECUUUUUULES- To understand how polymers are formed from small molecules and some of the factors which determine the properties of polymers.
  43. Properties of Matter- To show the concept of density.
  44. Rate Determining Step and Catalysts- This activity will allow the student to understand the rate determining step, the dependence of total rate on the rate determining step and the effect of a catalyst on rate.
  45. Rate of Solubility- This can be adapted for any grade. Discover factors affecting the rate of solution.
  46. Reaction Rates - Catalysis, Concentration, Surface Area, and Temperature- To observe factors affecting the rate of a chemical reaction.
  47. Redox Reactions- To enable the student to balance oxidation-reduction reactions by using the half reaction method.
  48. Secret Message- Using the characteristic of a chemical reaction to write a secret letter.
  49. Separation Of Mixtures And Compounds For K Through 12- To separate mixtures by using such techniques as solubility differences in water, filtration and evaporation.
  50. Solubility- To tell the difference between a soluble and an insoluble solution.
  51. The Chemistry of Fire and Other Oxidation Reactions- Realize that fuel and oxygen are necessary in order to have combustion.
  52. The Color Of Your Own: Mixing Paint- Students will be able to understand how to make simple old fashioned paint solutions.
  53. The Difference Between Acids and Bases Using Different Indicators- To identify the differences between acids and bases using litmus paper, pH paper and indicator solution.
  54. The History of Creation- The main objective is to give the child a general view of the universe, an experience of the varied properties of matter and an understanding of the laws which govern the universe.
  55. The Need for Normality- The materials here will show that not all salts are neutral and will demonstrate the necessity for measuring concentration using normality in titration experiments.
  56. The Six Solution Problem- The Six Solution Problem is a logic problem assuming that the student knows some basic reactions and solubility rules.
  57. Water from a Match: The Principles of Combustion- To investigate the chemistry of combustion and, to some extent, of photosynthesis; appropriate for grades 3-high school, with sophistication of explanations scaled appropriately
  58. World Of Plastics And Polymers- To examine and observe characteristics of different materials that are polymers.