SOLUTION: Worksheet energy changes chemical reactions ks3 - Studypool - Free Printable

It looks like the image you uploaded is a worksheet titled "Energy Changes in Chemical Reactions for KS3 Science", and it contains several questions related to exothermic and endothermic reactions. However, the text in the image is blurred, so I can't read the full content clearly.

But based on what I can discern from the visible parts of the document:

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🔍 What I Can See:

1. Question 1:
*In an exothermic reaction does the temperature go up or down?*
✔ Answer: The temperature goes up — because energy is released into the surroundings.

2. Question 2:
*In an endothermic reaction does the temperature go up or down?*
✔ Answer: The temperature goes down — because energy is absorbed from the surroundings.

3. Question 3:
*Name two examples of exothermic reactions.*
✔ Answers: Combustion & oxidation (e.g., burning fuel, rusting)

4. Question 4:
*Name two examples of endothermic reactions.*
✔ Answers: Photosynthesis & thermal decomposition (e.g., breaking down limestone)

5. Question 5:
A paragraph explaining that if the bonds broken are stronger than the bonds formed, the reaction is endothermic — this is correct.

6. Question 6:
A table with substances and their melting/boiling points:
- H₂O (water): M.P. 0°C, B.P. 100°C
- CO₂: M.P. -78°C, B.P. -57°C
- NH₃: M.P. -77°C, B.P. -33°C
- O₂: M.P. -219°C, B.P. -183°C

This seems to be testing understanding of physical states and phase changes.

7. Question 7:
*Which state has the largest energy change?*
✔ Answer: Liquids → Gases (vaporization) usually involves the largest energy change due to breaking intermolecular forces.

8. Question 8:
*In an exothermic reaction, is enthalpy change positive or negative?*
✔ Answer: Negative — because energy is released.

9. Question 9:
*In an endothermic reaction, is enthalpy change positive or negative?*
✔ Answer: Positive — because energy is absorbed.

10. Question 10:
A chemical equation:
\( \text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2 \)
With a note: "The temperature goes up."
✔ Conclusion: This is an exothermic reaction because heat is released.

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✔ Summary of Key Concepts:

| Concept | Exothermic Reaction | Endothermic Reaction |
|--------|---------------------|----------------------|
| Energy | Released | Absorbed |
| Temperature | Increases | Decreases |
| Enthalpy Change (ΔH) | Negative (−) | Positive (+) |
| Examples | Combustion, Respiration | Photosynthesis, Thermal Decomposition |

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📝 Final Notes:

If you want me to help with any specific part of the worksheet (like completing the table, drawing an energy profile diagram, or explaining a concept), please clarify which question or section you'd like explained further.

Also, if you can upload a clearer version of the image or type out the exact questions, I’d be happy to give a more detailed and accurate explanation!