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?

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?

GPT-4o mini · Answer

Here’s a breakdown of each situation and whether it represents a physical or chemical change:

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.
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.
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.
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.
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.
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.
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).
Fireworks exploding, giving off heat and light: This is a chemical change. The combustion of chemicals in fireworks results in new substances being formed.
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.
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).
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.
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.