Evidence of Chemical Reactions
Aligned to MS-PS1-2 — Next Generation Science Standards.
What this lesson teaches
When a chemical reaction happens, new substances form with different properties than the starting materials — such as a new color, a gas, an odor, or a temperature change.
Worked example
Mixing baking soda and vinegar produces bubbling gas and the mixture cools. The new properties — carbon dioxide gas and a different substance — are evidence a chemical reaction occurred, not just a mixing.
Practice questions
- Observe a data table of color, density, and melting point before and after, and decide whether a reaction happened.
- Compare two mixtures and identify which one shows evidence that a new substance formed.
- Explain why a color change alone is not always proof of a chemical reaction.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Evidencia de Reacciones Químicas
Cuando ocurre una reacción química, se forman sustancias nuevas con propiedades distintas a las de los materiales iniciales — como un color nuevo, un gas, un olor o un cambio de temperatura.
Ejemplo: Al mezclar bicarbonato con vinagre se produce un gas que burbujea y la mezcla se enfría. Las nuevas propiedades — el gas dióxido de carbono y una sustancia diferente — son evidencia de que ocurrió una reacción química, no solo una mezcla.
More Matter & Its Interactions lessons
Teach this lesson today
An AI tutor that guides with questions instead of just giving answers — all K–12 core subjects, every child in the family.
Start free — no card required