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6th grade · Science · Unit 4 of 17

Chemical Reactions

New substances form, and atoms are conserved.

What your child practices

Practices signs of chemical reactions, how properties change when new substances form, conservation of mass, and devices that release or absorb thermal energy through reactions.

Texas Essential Knowledge and Skills (TEKS) teks student expectation: 6.6(E) · evidence of chemical change such as a gas, a precipitate or a color change

How we explain it

Children can open this short lesson before they practice.

  1. In a chemical reaction, reactants change into new substances called products.
  2. Signs of a reaction: a gas forms, color changes, heat or light, or a solid appears.
  3. Atoms are conserved: they rearrange, but none are created or lost.
  4. Baking soda and vinegar make carbon dioxide gas. Iron with oxygen and water makes rust.

Example: Baking soda and vinegar fizz. What are the bubbles? A new gas is being made. This reaction makes carbon dioxide. Answer: carbon dioxide gas

Chemical Reactions in Texas

In the Texas Essential Knowledge and Skills (TEKS), this is unit 4 of 17 in 6th grade Science, after Density & Buoyancy and before Gravity & Friction.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Texas Education Agency (TEA)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Which is a chemical change?

    • Breaking glass
    • Burning a candle wick
    • Dissolving sugar
    • Freezing juice

  2. Question 2

    An endothermic reaction…

    • makes light only
    • releases thermal energy
    • absorbs thermal energy
    • has no products

  3. Question 3

    Substances made by a reaction are…

    • products
    • reactants
    • mixtures only
    • elements only

  4. Question 4

    Rust forms when iron reacts with…

    • oxygen and water
    • sunlight only
    • salt only
    • sugar

  5. Question 5

    An exothermic reaction…

    • releases no energy
    • absorbs thermal energy
    • makes things colder only
    • releases thermal energy

  6. Question 6

    2H₂ + O₂ → 2H₂O. How many oxygen atoms are on each side?

    • 3
    • 2
    • 1
    • 4

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