The Best Way to Teach Balancing Chemical Equations (Backed by Research)
- Androy
- Dec 12, 2021
- 7 min read
Updated: Mar 9
I used to think I had balancing chemical equations figured out.
I had my step-by-step method, and even a few tried-and-true tricks to help students navigate coefficients and subscripts. But every year, I’d watch my students make the same mistakes—randomly adding numbers, guessing their way through problems, or worse, changing subscripts instead of using coefficients.
One day, a student looked up from their worksheet, completely frustrated, and asked:
"Why do we even need to do this?"
And that’s when it hit me—I had been teaching balancing equations without fully addressing the ‘why.’
If you’ve ever had students struggle with balancing chemical equations—or if you’ve ever felt like no matter how many times you explain it, it just doesn’t stick—then this post is for you.
In this research-backed guide, we’ll dive into:
Why traditional methods fail when teaching balancing equations
How to introduce balancing in a way that actually makes sense
A step-by-step scaffolded approach that moves from hands-on experiences to symbolic equations
Practical classroom strategies and activities to help students build confidence
Why Do Students Struggle with Balancing Chemical Equations?
Many students approach balancing equations like a math puzzle rather than a representation of real-world chemical reactions.
Laugier and Dumon (2004) found that students often view balancing as a series of arbitrary rules rather than a process grounded in the Law of Conservation of Mass.
This explains why so many of them:
Change subscripts instead of adjusting coefficients
Guess and check without understanding why balancing is necessary
Struggle to connect the symbolic equation to the actual reaction happening at the atomic level
Johnstone's Chemistry Triangle
Johnstone (1993) and Devetak et al. (2004) assert that teaching students only at the symbolic level (chemical formulas and reaction equations) is ineffective. Instead, we need to engage students at multiple levels of representation:
Macroscopic (observable changes in lab experiments)
Submicroscopic (molecular-level diagrams and models)
Symbolic (balanced equations)
When we teach balancing equations with all three levels in mind, students develop a deeper understanding and perform better on reaction stoichiometry problems later on.
Step 1: Start with the Law of Conservation of Mass (Macroscopic Level)
Why Do We Balance Equations?
Before throwing equations at students, we need to show them why balancing is necessary. This begins with a hands-on experiment demonstrating the Law of Conservation of Mass—because if they don’t believe mass is conserved, why would they care about balancing equations?
Classroom Activity: Conservation of Mass in Action
Have students predict, observe, and analyze the mass before and after a chemical reaction.
Try these simple lab activities:
Acid-carbonate reaction in an open vs. closed system
Combustion of a candle (discussing why mass "disappears")
A precipitation reaction (addressing misconceptions like “solids are heavier than liquids”)
What to Ask Students:
Does the total mass before and after the reaction stay the same? Why or why not?
If mass seems to change, what might be happening?
How does this relate to why we balance chemical equations?
Piaget and Inhelder (1974) observed that students often assume a precipitate increases a system’s mass simply because “solids are heavier than liquids.”
This misconception reflects a sensory-driven, naïve model of matter rather than a true understanding of conservation principles.
To help students grasp why we balance equations, use observable experiments that clearly demonstrate the law of conservation of mass.
Addressing any unexpected discrepancies in experimental results reinforces the concept and challenges their initial assumptions, leading to deeper understanding.
Step 2: Transition to the Symbolic Level (Basic Balancing with Mass Calculations)
Once students accept conservation of mass, we can show how a balanced equation mathematically follows this principle.
Classroom Activity: Checking Mass Balance in Equations
Give students a simple unbalanced reaction.
Have them calculate the total atomic mass of reactants vs. products before balancing.
Then, introduce balancing equations as a way to correct mass imbalances.
Example:
Unbalanced Equation: H₂ + N₂ → NH₃
Mass Before: Hydrogen = 2g, Nitrogen = 28g (Total = 30g)
Mass After: NH₃ = 17g (Clearly imbalanced!)
Balanced Equation: 3H₂ + N₂ → 2NH₃ (Mass before = Mass after)
Now, students see that coefficients fix the imbalance, reinforcing why balancing equations matters.
Step 3: Visual Balancing (Submicroscopic Level of Representation)
At this point, students need a visual way to practice balancing before jumping into symbolic equations. Research by Mayer (2009) shows that students learn best when they process concepts visually and symbolically at the same time.
Phase 1: Using Concrete Examples (Optional but Helpful)
This phase is especially useful for younger students or those needing extra support. Using physical manipulatives like MolyMods™, candy, or even digital tools helps students visualize how atoms combine in fixed ratios. Here's an affordable molecular modeling kit I use in my classroom.
During distance learning, I used a Google Slides™ activity where colored shapes represented elements in a "chemical formula." The proportions of different shapes couldn't change, reinforcing the idea that subscripts remain constant while coefficients adjust the number of molecules. This hands-on approach helps students grasp why we need multipliers (coefficients) when balancing equations.
Phase 2: Introducing Sub-Microscopic Diagrams
Once students understand the concept with tangible models, they transition to diagrams representing sub-microscopic particles.
Instead of using abstract formulas immediately, they see pictorial representations of atoms and molecules.
This step strengthens their ability to connect the symbolic level (chemical formulas) with the particle level, engaging their visual learning channels (Mayer, 2009).
At this stage, students begin counting atoms and adjusting coefficients to ensure conservation of mass.
Phase 3: Moving to Symbolic Equations
With a strong foundation in visual and conceptual understanding, students are ready to balance chemical equations using symbols alone. Since they’ve already activated their visual processing skills, the leap to abstract notation becomes smoother.
Want to try this approach in your own classroom? You can download the Google Slides™ digital resources here.
Teaching Tip: Before jumping into equations, make sure students grasp the difference between subscripts and coefficients. Otherwise, they’ll keep making the mistake of changing subscripts to balance equations.
Step 4: Introduce the Inspection Method ("Ping Pong" Balancing)
Once students are comfortable counting atoms and using coefficients, they can begin balancing by inspection.
Students should only be encouraged to balance equations by inspection once they have a solid understanding of why they’re doing it, how to write chemical formulas, and the difference between coefficients and subscripts.
If your students need more practice with writing and understanding chemical formulas, you might find this resource helpful.
Balancing by inspection requires students to count the number of atoms of each element on both sides of the equation and adjust coefficients to ensure they are equal. While some students will grasp this process conceptually, others may rely on trial and error, which can lead to frustration.
Niaz and Robinson (1992) caution that balancing without conceptual understanding can be challenging, as it requires strong reasoning skills and a firm grasp of ratios and proportions.
Ensuring students have this foundation before moving to inspection will lead to more meaningful and confident problem-solving. Here's what you should do:
Use simple reactions first
Encourage logical reasoning, not guessing
Reinforce the connection to conservation of mass
Once students consistently apply balancing principles, they’re ready for complex reactions.
Final Thoughts: Rethinking How We Teach Balancing Equations
If your students are struggling with balancing equations, it’s worth revisiting how we introduce the topic.
Research confirms that a scaffolded, multi-representation approach (macroscopic → visual → symbolic) leads to deeper understanding and long-term retention.
📥 Want a ready-to-use digital resource that follows this exact approach?
Grab my Balancing Chemical Equations Digital Workbook—it’s interactive, Google Slides™ compatible, and designed to help students master balancing equations step by step.
What strategies have worked for YOUR students? Drop a comment below—I’d love to hear your thoughts!
References:
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Ben-Zvi R., Eylon B. and Silberstein J., (1988), Theories, principles and laws, Educ. Chem., 25, 89-92.
Chittleborough G. D., (2004), The role of teaching models and chemical representations in developing students’ mental models of chemical phenomena, Unpublished doctoral thesis, from http://adt.curtin.edu.au/theses/available/adt-WCU20041112.125243/ accessed 21/11/2021.
Chittleborough G. and Treagust D., (2008), Correct interpretation of chemical diagrams requires transforming from one level of representation to another, Res. Sci. Educ. 38, 463–482.
Davidowitz B., (2006), Multiple choice or multiple guess, that is the question: reflections on assessment in a first year chemistry course, For Engineering Educators, 10, 15-17.
Devetak I., Urbančič K., Grm K. S. W., Krnel D. and Glažar, S., (2004), Submicroscopic representations as a tool for evaluating students’ chemical conceptions, Acta Chim. Slov., 51, 799-814.
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Johnstone A. H., (1993), The development of chemistry teaching: a changing response to changing demand, J. Chem. Educ., 70, 701-705.
Laugier A. and Dumon A., (2004), The equation of reaction: a cluster of obstacles which are difficult to overcome, Chem. Educ. Res. Pract., 5, 327-342.
Mayer R. E., (2002), Cognitive theory and the design of multimedia instruction: an example of the two-way street between cognition and instruction, New Dir. Teach. Learn., 89, 55-71.
Nakhleh M. B., Lowry K. A. and Mitchell R. C., (1996), Narrowing the gap between concepts and algorithms in freshman chemistry, J. Chem. Educ., 73, 758-762.
Piaget, J. & Inhelder, B. (1974). The child.s construction of quantities. London: Routledge, Kegan Paul
Treagust D and Chittleborough G., (2001), Chemistry: a matter of understanding representations, in J. Brophy, (ed.), Subject-specific instructional methods and activities (Vol. 8,), JAI: Elsevier Science Ltd, pp. 239-267.
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