Week 3: Energy in Chemical Reactions - Grade 7 Science - Study Guide

REF STUDY GUIDE: Big Ideas Use to answer form questions

1.Bond Energy and Heat: Breaking chemical bonds requires energy input, while forming new bonds releases energy — the balance between the two determines whether a reaction heats up or cools down its surroundings.

2.Exothermic vs. Endothermic: Exothermic reactions release more energy than they absorb (surroundings warm up), while endothermic reactions absorb more energy than they release (surroundings cool down).

3.Engineering with Energy: Hot packs and cold packs are engineered devices that harness exothermic and endothermic reactions to transfer thermal energy for practical, real-world purposes.

DRAW KEY TERMS Google each → Images tab → sketch what you see

Bond energy

Energy stored in chemical bonds between atoms

Activation energy

Energy needed to start a chemical reaction

exothermic

Reaction that releases energy to surroundings (gets hot)

endothermic

Reaction that absorbs energy from surroundings (gets cold)

WRITE FOCUS QUESTION Your initial thinking

At a soccer game, the trainer snaps a plastic pack and it instantly turns ice-cold on a player's twisted ankle. Meanwhile, another player cracks open a different pack and it heats up in seconds. Both started at room temperature — yet one got hot and the other got cold.

Why do hot packs get hot but cold packs get cold?

I think...TODO: author answer text

WRITE AFTER HOOK FORM Reflect before continuing

I learned that... TODO: author answer text

Station 1 — Energy Diagrams

I observed that... TODO: author answer text

This shows that... TODO: author answer text

The key concept is... TODO: author answer text

Station 2 — Bond Energy Model ⭐ CRITICAL

The data shows... TODO: author answer text

This connects to... TODO: author answer text

The main idea is... TODO: author answer text

This connects to what we learned because...

I can apply this by... TODO: author answer text

DRAW CONCEPT MODEL Show your understanding visually

Draw a model that shows the main concept. Include labels and arrows to explain relationships.

TODO: author answer text

Labels included

Relationships shown

Key terms used

CHECK TEST YOUR THINKING Rate each: FALSE ← 1–2–3–4–5 → TRUE

1. Cold packs add coldness to your body, just like hot packs add heat.

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2. Temperature and heat are the same thing — they both measure how much thermal energy an object has.

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3. Energy can be created during an exothermic reaction — that is where the heat comes from.

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4. An endothermic reaction absorbs heat, so the products must end up at a higher temperature than the reactants.

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5. Breaking chemical bonds releases energy, which is why snapping a cold pack makes it cold.

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Pick any TWO statements — especially any you rated 2, 3, or 4. Justify your rating with evidence:

Statement #___ — I rated it ___ because:

THINK SCIENTIST CIRCLE DEBRIEF Reflect after your Scientist Circle discussion

AHA! Moment

The one I changed my thinking most about is... TODO: author answer text

Remaining Question

I still wonder... TODO: author answer text

WRITE FOCUS QUESTION REVISIT Final written response

Why do hot packs get hot but cold packs get cold?

TODO: author answer text