Concept Presentation: Concept Presentation: Writing and Balancing Writing and Balancing ReactionsReactions

Presented by: Ann Hu

OpenerOpener Song on: Don’t break the Law

AgendaAgenda

Background Information: Prior Knowledge & Overall place within the curriculum

Comparison of Grade 10 vs. Grade 11 Lesson Sequence + Common

Misconceptions Accommodations Application Activities Q & A

Background InformationBackground Information Prior Knowledge

◦ Counting Atoms & Building Molecules (grade 9)◦ Connections of chemical reactions to the

environment◦ Types of bonding◦ Chemical Naming and Formula◦ Lewis Dot Diagrams

Location within the course◦ In grade 10, toward the middle of the chemistry unit.

Chemical and Physical Changes Types of Bonding & Naming Writing and Balancing Equation Types of Reaction Properties of Acids and Bases Neutralization

◦ In grade 11, within unit 2.

SNC2D vs. SCH3USNC2D vs. SCH3UGRADE 10 (Academic)

C1. analyse a variety of safety and environmental issues associated with chemical reactions, including the ways in which chemical reactions can be applied to address environmental challenges

C1.1 analyse, on the basis of research, various safety and environmental issues associated with chemical reactions and their reactants and/or

product(s)

C1.2 analyse how an understanding of the properties of chemical substances and their reactions can be applied to solve environmental challenges

C2.4 use an inquiry process to investigate the law of conservation of mass in a chemical reaction

C3.2 explain, using the law of conservation of mass and atomic theory, the rationale for balancing chemical equations

C3.4 write word equations and balanced chemical equations for simple chemical reactions

GRADE 11 (University)-selected

D2. investigate quantitative relationships in chemical reactions, and solve related problems;

C2.2 write balanced chemical equations to represent synthesis, decomposition, single displacement, double displacement, and combustion reactions, using the IUPAC nomenclature system

D2.3 solve problems related to quantities in chemical reactions by performing calculations involving quantities in moles, number of particles, and atomic mass

D2.5 calculate the corresponding mass, or quantity in moles or molecules, for any given reactant or product in a balanced chemical equation as well as for any other reactant or product in the chemical reaction

2D introduced in the form of simple equations whereas 3U introduced as part of the process.

2D used it as extension of “the Law of Conservation of Mass”, and 3U used it as introduction to “Stoichiometry”

Lesson SequenceLesson Sequence

•Lesson 1: Counting Atoms•Lesson 2: Lab-Law of Conservation of Mass

•Lesson 3: Writing Equations•Lesson 4: Balancing Equations Day1+

Lesson 5: Balancing Equations Day 2•Lesson 6-7: Types of Reactions

Lesson 1: Counting AtomsLesson 1: Counting Atoms Focus: Review the use of subscript and introduce

the use of coefficient. Plan

◦ Warm Up: Use analogy to describe atoms vs. molecules, elements vs. compound

◦ Dry Lab (molecular model kits)◦ Placemat Activity (Team Game Challenge)

Misconception #1: Students may place subscript as superscript or coefficient◦ Cause: Students may have connected the

ideas of subscript with exponent◦ Suggestion: reinforce superscript is for charge

whereas subscript is to indicate number

Back Lesson menu

Lesson 2: Lab-Law of Conservation of MassLesson 2: Lab-Law of Conservation of Mass Focus: Through inquiry, students will be able to

observe Law of Conservation of Mass. Plan

◦ Lab

◦ Video: http://www.youtube.com/watch?v=QjVYz00-Kxc

Misconception #2: Gases has no mass, therefore don’t follow the Law of Conservation of Mass◦ Cause: Gases tend to escape into the atmosphere◦ Suggestion: reinforce the Law of Conservation of

Mass include ALL particlesBack Lesson menu

Copper (II) Hydroxide solutionSodium sulphate solution

Lesson 3: Writing EquationsLesson 3: Writing Equations Focus: How to write word equations. Plan

◦ Warm Up: A reaction produces products lighter than the reactants, explain.

◦ Content◦ TPS: misconceptions◦ Group Activity

Misconceptions #3: Equal signs may be mistakenly used in place of the arrow in a chemical equation◦ Cause: relating math to science◦ Suggestion: reinforce products and reactants are

completely different (e.g. H2 +O2H2O) Common mistakes: ↑ can be used on both side of

the reactions; ∆ and electricity on the reactant sideBack Lesson menu

Lesson 4: Balancing Equation Day 1Lesson 4: Balancing Equation Day 1 Focus: Relating Law of Conservation of Mass to

Balancing equations (simple) Plan

◦ Differentiated instruction for different learners. Proportional Reasoning Draw molecules Bingo activity

◦ Online resource

Back Lesson menu

H2+Cl2HCl changed to H2+Cl22HCl

Lesson 5: Balancing Equation Day 2Lesson 5: Balancing Equation Day 2 Focus: Relating Law of Conservation of Mass to

Balancing equations (more complex) Plan

◦ Group Challenge◦ Online resource

N2+H2NH3 & Na+H2ONaOH+H2

Misconceptions Within Balancing EquationMisconceptions Within Balancing Equation Misconceptions #4: Changing Subscripts in

Chemical Formulas Plan◦ Cause: unable to count atoms, bonding, both

sides equal◦ Suggestion: shows the effect of changing

subscript; Reinforce the difference between coefficients vs. Subscript

Misconceptions #5: “Sum of coefficients before and after must be the same” & “Whatever the subscript is for an element on the reactant side of the equation, the same subscript must be used for that element on the product side”◦ Cause: the Law of Conservation of Mass ◦ Suggestion: Bingo chipsBack

Lesson menu

Misconceptions Within Balancing EquationMisconceptions Within Balancing Equation Misconceptions #6: Balancing Equations is strictly

algorithmic exercise◦ Cause: no connection that the letter represents a

“molecule”.◦ Suggestion: ask students to draw the molecules

or use of words to explain their understanding

Back Lesson menu

McGoey, J., 2007

Lesson 6/7: Types of ReactionLesson 6/7: Types of Reaction Focus: Continuation of the previous concepts Plan

◦ Include application of Balancing Reaction.

Back Lesson menu

AccommodationsAccommodations

Bingo activity can provide hands on activity.Whiteboard ideas and group work helps with

communication.Encourage ELL students to translate the

steps into their own language.Accommodate ELL students in the evaluation

by providing language easy test, and for Special Needs according to ILP.

ApplicationApplication Tied all concepts of chemical reaction together.

◦ EUT: Grocery store Chemical

ActivitiesActivities

2 Stations.◦ Bingo Activity◦ Application of Activity

Write your result on the whiteboard (3-2-1)

Questions?Questions? Any Questions?