Question
These questions are physical change or chemical change first is you burn a piece of toast when leaving it in the oven the bread is now black is that a physical change or a chemical change you forget to dry a knife after washing it. The next time you look at it, you see reddish brown spots on the blade. Is that physical or chemical change next you use a blow dryer to dry your hair. Is that physical or chemical change a straight piece of wire is coiled to form a sprain is that physical or chemical change Color is dropped into water to give it color, physical or chemical change chewing food to break it down into smaller pieces represents a chemical or physical change but the changing of starch into sugars by enzymes and the digestive system represents a physical or chemical change and a firework show the fireworks explode giving off heat and might is that physical or chemical change you can crush a piece of chalk into a fine powder is that physical or chemical change you dissolve chocolate syrup into a glass of milk and the milk is now shade of brown physical or chemical change you toast a marshmallow over a campfire until it has a golden brown crust. Is that physical or chemical change and it begins to glow a bright yellow color and warm? Is that physical or chemical change?
Answers
GPT-4o mini
Here’s a breakdown of each situation and whether it represents a physical or chemical change:
1. **Burning a piece of toast:** This is a **chemical change**. The bread undergoes combustion, resulting in new substances (carbon, ash) and a change in color.
2. **Forget to dry a knife and see reddish brown spots (rust):** This is a **chemical change**. The formation of rust (iron oxide) is a chemical reaction between iron, oxygen, and moisture.
3. **Using a blow dryer to dry your hair:** This is a **physical change**. The heat causes water to evaporate, but it does not change the chemical structure of your hair.
4. **Coiling a straight piece of wire to form a spring:** This is a **physical change**. The wire's shape changes, but its chemical properties remain unchanged.
5. **Color being dropped into water to give it color:** This is a **physical change**. The dye disperses in the water, but no chemical reaction occurs.
6. **Chewing food to break it down into smaller pieces:** This is a **physical change**. The food's size and shape change, but its chemical structure remains the same.
7. **Changing starch into sugars by enzymes in the digestive system:** This is a **chemical change**. The enzymes break down starches into different chemical substances (sugars).
8. **Fireworks exploding, giving off heat and light:** This is a **chemical change**. The combustion of chemicals in fireworks results in new substances being formed.
9. **Crushing a piece of chalk into a fine powder:** This is a **physical change**. The chalk changes in size and shape, but its chemical composition remains unchanged.
10. **Dissolving chocolate syrup into a glass of milk:** This is a **physical change**. The syrup disperses in the milk, but the chemical identity of both substances remains unchanged (although it does create a new mixture).
11. **Toasting a marshmallow over a campfire until it has a golden brown crust:** This is a **chemical change**. The heat causes chemical reactions in the sugars and proteins, resulting in new substances.
12. **Marshmallow begins to glow a bright yellow color and warm:** This is also a **chemical change**. The glowing indicates a chemical reaction taking place as the sugars caramelize and new substances are formed.
In summary, burning toast, rusting, enzyme activity, fireworks, and toasting a marshmallow are chemical changes, while drying hair, coiling wire, dyeing water, chewing food, crushing chalk, and dissolving syrup are physical changes.
1. **Burning a piece of toast:** This is a **chemical change**. The bread undergoes combustion, resulting in new substances (carbon, ash) and a change in color.
2. **Forget to dry a knife and see reddish brown spots (rust):** This is a **chemical change**. The formation of rust (iron oxide) is a chemical reaction between iron, oxygen, and moisture.
3. **Using a blow dryer to dry your hair:** This is a **physical change**. The heat causes water to evaporate, but it does not change the chemical structure of your hair.
4. **Coiling a straight piece of wire to form a spring:** This is a **physical change**. The wire's shape changes, but its chemical properties remain unchanged.
5. **Color being dropped into water to give it color:** This is a **physical change**. The dye disperses in the water, but no chemical reaction occurs.
6. **Chewing food to break it down into smaller pieces:** This is a **physical change**. The food's size and shape change, but its chemical structure remains the same.
7. **Changing starch into sugars by enzymes in the digestive system:** This is a **chemical change**. The enzymes break down starches into different chemical substances (sugars).
8. **Fireworks exploding, giving off heat and light:** This is a **chemical change**. The combustion of chemicals in fireworks results in new substances being formed.
9. **Crushing a piece of chalk into a fine powder:** This is a **physical change**. The chalk changes in size and shape, but its chemical composition remains unchanged.
10. **Dissolving chocolate syrup into a glass of milk:** This is a **physical change**. The syrup disperses in the milk, but the chemical identity of both substances remains unchanged (although it does create a new mixture).
11. **Toasting a marshmallow over a campfire until it has a golden brown crust:** This is a **chemical change**. The heat causes chemical reactions in the sugars and proteins, resulting in new substances.
12. **Marshmallow begins to glow a bright yellow color and warm:** This is also a **chemical change**. The glowing indicates a chemical reaction taking place as the sugars caramelize and new substances are formed.
In summary, burning toast, rusting, enzyme activity, fireworks, and toasting a marshmallow are chemical changes, while drying hair, coiling wire, dyeing water, chewing food, crushing chalk, and dissolving syrup are physical changes.