Chemistry worksheet focusing on distinguishing between physical and chemical properties and changes, featuring classification tasks and examples.

Here are the answers to your worksheet.

1. Classify as Physical or Chemical

Reasoning:
* Physical Properties describe what something is like (color, shape, size) without changing what it is made of.
* Chemical Properties describe how a substance reacts with other things to become something new.

| Property | Physical | Chemical |
| :--- | :---: | :---: |
| Red color | X | |
| Solubility (ability to dissolve) | X | |
| Density | X | |
| Supports combustion (burning) | | X |
| Reacts with acid to form H2 | | X |

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2. Classify as C, E, or I

Reasoning:
* C (Chemical): Describes how it changes into a new substance (reactivity).
* I (Intensive Physical): A property that stays the same no matter how much stuff you have (e.g., density, color).
* E (Extensive Physical): A property that changes depending on how much stuff you have (e.g., mass, volume).

* Color: This is physical and doesn't change based on amount. -> I
* Mass: This is physical, but if you add more stuff, the mass goes up. -> E
* Flammability: This describes burning (a chemical reaction). -> C
* Density: This is physical. A gold coin has the same density as a gold brick. -> I
* Reacts with acid...: This describes a chemical reaction. -> C

Answers:
* Color: I
* Mass: E
* Flammability: C
* Density: I
* Reacts with acid to form hydrogen gas: C

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3. Identify as Physical (P) or Chemical (C) Changes

Reasoning:
* Physical Change (P): The object looks different (shape, state of matter), but it is still the same material. You can often reverse these.
* Chemical Change (C): A new substance is created. Look for clues like burning, rotting, rusting, cooking, or bubbling gas.

i. NaCl dissolves in water: It’s still salt, just mixed in water. -> P
ii. Ag (silver) tarnishes: Tarnish is a new layer formed by reacting with air. -> C
iii. An apple is cut: It's just smaller pieces of apple. -> P
iv. Heat changes water to steam: It is still water ($H_2O$), just a gas now. -> P
v. Baking soda reacts with vinegar: Bubbles form (gas), creating a new substance. -> C
vi. Milk sours: Bacteria changed the milk into something else (acid). -> C
vii. Sugar dissolves in water: It’s still sugar, just mixed in water. -> P
viii. Wood rots: Rotting breaks down the wood into soil/compost. -> C
ix. Pancakes cook: Heat changes the batter into a solid cake; you can't un-cook it. -> C
x. Grass grows: Growing involves photosynthesis, which creates new plant material. -> C

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Final Answer:

1. Classification Table
* Red color: Physical
* Solubility: Physical
* Density: Physical
* Supports combustion: Chemical
* Reacts with acid to form H2: Chemical

2. Property Codes
* Color: I
* Mass: E
* Flammability: C
* Density: I
* Reacts with acid to form hydrogen gas: C

3. Physical (P) or Chemical (C) Changes
* i. P
* ii. C
* iii. P
* iv. P
* v. C
* vi. C
* vii. P
* viii. C
* ix. C
* x. C