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Science · Grade 7

Chemical Reactions and Conservation

Learners identify substances by their characteristic properties, then use property data from before and after an interaction to decide whether a new substance formed. They build atoms into molecules, read simple formulas and count atoms, and explain a chemical reaction as the same atoms rearranging into new substances. They test conservation of mass in closed and open containers and balance a few very simple equations by counting atoms.

  • 5 lessons
  • About 115 minutes
  • Reactions and conservation check: 11 questions
  • Ways to answer: balance equations, choose an answer, draw a graph, highlight a text, match pairs and type a number
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What learners will discover

  • Identify a pure substance by its characteristic properties, such as density, melting point, boiling point and solubility, and explain why mass, volume and shape cannot identify it.
  • Use observations and property data from before and after an interaction to decide whether a chemical reaction (a new substance) or a physical change occurred.
  • Model atoms and molecules: read simple chemical formulas, count the atoms in molecules, and distinguish elements from compounds.
  • Explain conservation of mass in a reaction as the same atoms rearranging, count atoms before and after, balance very simple equations, and predict balance readings in closed and open containers.

Lessons

  1. Substances and their characteristic properties 8 steps4 practiceabout 20 min
  2. Physical change or chemical reaction? 8 steps4 practiceabout 22 min
  3. Atoms, molecules and formulas 8 steps4 practiceabout 20 min
  4. Reactions rearrange atoms 8 steps4 practiceabout 20 min
  5. Conservation of mass in closed and open systems 8 steps4 practiceabout 22 min
  6. Reactions and conservation check 11 questions at the end

Keep exploring

Games to practice with

  • Bridge LabBuild a bridge from beams, brace it with triangles, and stay on budget.
  • Circuit Workshop 3DWire up batteries, bulbs and switches on a 3D workbench.
  • River MysterySomething changed the river. Sample sites with a limited budget, follow the evidence and find where the change begins.

More 7th grade science

Guide for grown-ups