Chemistry homework worksheet on chemical and physical changes and properties.

Here are the answers to your homework assignment.

Part 1: Chemical (C) or Physical (P) Change

*Look at whether a new substance is being made. If it’s just changing shape or state (like melting), it’s physical. If it burns, rots, or reacts, it’s chemical.*

Column 1:
* Boil: P (It turns into steam, but it's still water.)
* Burn: C (Fire changes the wood/paper into ash and smoke.)
* Condense: P (Gas turns back into liquid.)
* Corrode: C (Like rusting; the metal breaks down.)
* Crumple: P (Just changing the shape of paper.)
* Tarnish: C (Silver reacts with air and gets dull.)
* Color: P (Usually refers to adding dye or painting, which covers the surface.)

Column 2:
* Ferment: C (Yeast changes sugar into alcohol/gas.)
* Melt: P (Solid turns to liquid, like ice to water.)
* Rust: C (Iron reacts with oxygen.)
* Crush: P (Breaking into smaller pieces.)
* Freeze: P (Liquid turns to solid.)
* Frying: C (Cooking changes the food permanently.)
* Cook: C (Heat changes the ingredients.)

Column 3:
* Oxidize: C (Reacting with oxygen, like an apple turning brown.)
* Grind: P (Making something into powder.)
* Rot: C (Decomposing.)
* Vaporize: P (Turning into gas.)
* Photosynthesis: C (Plants make their own food using sunlight.)
* Paint: P (Covering a surface with a layer of color.)

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Part 2: How to make Physical and Chemical Changes

*Physical = Cut, tear, melt, freeze. Chemical = Burn, cook, rot, react.*

| Item | Physical Change | Chemical Change |
| :--- | :--- | :--- |
| Newspaper | Tear it into pieces | Burn it in a fire |
| Tree log | Chop it into firewood | Burn it in a fireplace |
| Vinegar | Freeze it into ice cubes | Mix it with baking soda (it fizzes!) |
| Hair | Cut it with scissors | Dye it a different color |
| Skin | Get a suntan (changes color/texture) | Get a sunburn (damages cells) |

*(Note: For Skin, "Cutting" is also a physical change, but "Suntan/Sunburn" is a common science example for changes caused by energy.)*

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Part 3: Facts related to Chemical (C) or Physical (P) Properties/Changes

Left Column:
* Indicates how a substance reacts to another: C (Reactivity is chemical.)
* Observable using one of the five senses: P (Color, smell, and texture are physical properties.)
* Involves a change in size, shape, or phase: P
* Molecules of substance change: C (New molecules mean a new substance.)
* No new substance is formed: P

Right Column:
* A change in physical and chemical properties: C (Chemical changes alter both.)
* Molecules of the substance do not change: P
* A new substance is formed: C
* Matter of the substance is not destroyed: P (In physical changes, the stuff stays the same.)
* Has flammability and can rust: C (These are chemical properties.)

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Final Answer:

Part 1:
Boil: P | Ferment: C | Oxidize: C
Burn: C | Melt: P | Grind: P
Condense: P | Rust: C | Rot: C
Corrode: C | Crush: P | Vaporize: P
Crumple: P | Freeze: P | Photosynthesis: C
Tarnish: C | Frying: C | Paint: P
Color: P | Cook: C

Part 2:
* Newspaper: Physical: Tear it up / Chemical: Burn it
* Tree log: Physical: Chop it / Chemical: Burn it
* Vinegar: Physical: Freeze it / Chemical: Mix with baking soda
* Hair: Physical: Cut it / Chemical: Dye it
* Skin: Physical: Lotion/Moisturize (or Tan) / Chemical: Sunburn

Part 3:
Indicates how a substance reacts to another: C
Observable using one of the five senses: P
Involves a change in size, shape, or phase: P
Molecules of substance change: C
No new substance is formed: P
A change in physical and chemical properties: C
Molecules of the substance do not change: P
A new substance is formed: C
Matter of the substance is not destroyed: P
Has flammability and can rust: C