Unpacking the problem solving process


My year one class are working on Topic 1 Stoichiometric Relationship. I have been using these particular problems for



years because my students always love solving them.They like how they model ‘real’ world problems and they always lead to interesting questions, like “How do camels store water?”

2.1 The mole concept

Peer Assessment

I use this activity as a formative assessment to help guide further teaching and learning. I assign a different problem to each pair of students and have them work collaboratively to communicate their problem solving process. They then swap solutions and do a peer assessment.

What struck them about the problem solving process?

  • A clearly laid out process helps reveal errors in reasoning.
  • There can be more than one ways to approach a problem and this is OK as long as the reasoning used is sound.

But more importantly they come to understand that

Showing the problem solving process is more important than just getting the answer because revealing your thinking in this way can be used to guide future learning.

Chemistry syllabus & cross curricular links 1.2 The mole concept
Understandings, applications & skills Essential idea The mole makes it possible to correlate the number of particles with the mass that can be measured.Understandings Students should know that

  1. Molar mass (M) has the unit gmol-1
  2. The number of significant figures in a result is based on the figures given in the data.

Applications and skills Students should be able to

  1. Calculate the molar masses of molecules and formula units.
  2. Solve problems involving the relationships between the amount of substance in moles and the mass in grams.
Learner Profile Inquirers, Knowledgeable, Thinkers
IB Approaches to Teaching Conceptually focused, Collaborative, Contextualized.
IB Approaches to Learning Thinking skills, Communication skills
Assessment Formative



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