Chemical Reactions Unit miss E. Mac's Class

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ABOUT THE CHEMICAL REACTIONS LESSON

  1. Chemical Reactions Unit  Miss E. Mac's Classic
  2. Chemical Reactions Unit  Miss E. Mac's Classification
  3. Chemical Reactions Unit  Miss E. Mac's Class Of
  4. Chemical Reactions Unit  Miss E. Mac's Classics

This lesson is appropriate for children ages 11 and up. Students are introduced to atoms, molecules, compounds, and mixtures, using LEGO® bricks as atoms. In an engaging hands-on wet lab, students experience a chemical reaction and then model the same reaction with LEGO bricks. This lesson is also offered as a 3-hour academic field trip LEGO Chemistry at the Edgerton Center.

Download the Molecule Sets Overview or read the Rationale for using LEGO bricks as atoms.

  1. Start studying Chemical Reactions Unit Test. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
  2. Unit I: Atomic Theory Unit II: Chemical Reactions Unit III: Gases Unit IV: Electronic Structure and Bonding We begin this chapter by describing the relationship between the mass of a sample of a substance and its composition.
  3. This lesson is based on California's Middle School Integrated Model of NGSS and is a culminating activity for my chemical reactions unit. NGSS Performance Expectation (PE): (MS-PS1-2) Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occured.
  4. School Information. Educators apply here to access accessments. Approval may take one to two days.

MOLECULE SET MATERIALS

We are no longer able to sell Molecule Sets, unfortunately. Please visit our Information for Edgerton Center Molecule Sets webpage that describes how to put your own set together.

The following LEGO bricks are the minimum required (per kit/2 students) for the Chemical Reactions Lesson:

Chemical Reactions Lesson 7 Lesson Plan David V. Fansler Describing Chemical Change Objectives: Write equations describing chemical reactions using appropriate symbols; Write balanced chemical equations when given the names or formulas of the reactants and products in a chemical reaction - Word Equations o Every minute of everyday, there are.

  • 6 red 2x4
  • 2 pink 2x4
  • 2 light green 2x4
  • 2 black 2x4
  • 1 green 2x4
  • 4 white 1x2

Chemical Reactions Mats (per kit/2 students):

Student Worksheets:

TEACHING THE CHEMICAL REACTIONS LESSON

Co-Teaching Video from BLOSSOMS:

Teacher Guides and Resources:

MIT Edgerton Molecule videos on our YouTube channel:

  • Chemical Reactions Wet Lab Video (7.5 min)

CURRICULUM STANDARDS

This lesson meets the following items of the Massachusetts State Frameworks for grades 6-8, Physical Sciences Strand: Elements, Compounds & Mixtures:

5. Recognize that there are more than 100 elements that combine in a multitude of ways to produce compounds that make up all of the living and nonliving things that we encounter.

6. Differentiate between an atom (the smallest unit of an element that maintains the characteristics of that element) and a molecule (the smallest unit of a compound that maintains the characteristics of that compound).

7. Give basic examples of elements and compounds.

8. Differentiate between mixtures and pure substances.

10. Differentiate between physical changes and chemical changes.

ADDITIONAL RESOURCES

Document Versions prior to June 2012:

LEGO®, the LEGO logo, and the brick and knob configurations are trademarks of the LEGO group, used here with permission. ©MIT. All rights reserved.

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)

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

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.

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.

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.

Chemical Reactions Unit  Miss E. Mac's Classic

Unit miss

Turn in 1 assignment for 20 total Research Points.

Midpoint Quiz

Chemical Reactions Unit  Miss E. Mac's Classification

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).

Chemical Reactions Unit  Miss E. Mac's Class Of

  • 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!

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).

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.