How is toast a chemical change/reaction?

Question

I've read about how bread becoming toast is a chemical change/reaction, but I don't know why. Can someone please explain this for me? =]

Answer 1

bread + heat ---> toast

Bread is a complex mixture of sugars, complex carbohydrates, proteins, fats, and water. Heating the bread to make toast accomplishes the following reactions (among many others):
1. Caramelization of sugars
2. Low level burning (combustion) of surface carbohydrates
3. Removal (boiling off) of water
4. Denaturation of proteins (gluten and others)
5. Fats get hot enough to "fry" carbs and protein on a micro scale

Done!

Answer 2

Popcorn pops because the water in the kernel heats up and turns into steam. Its like a pressure cooker that got way to hot, and explodes. However, hot water vapor is still H20 just like it was in liquid or solid form. A chemical reaction would be those burnt popcorn bits that are always on the bottom of the bag or sides of the kettle. That's carbohydrates in the corn reacting with oxygen and producing smoke, CO2, H20 vapor and carbon residue. Because the chemical formulas of the products aren't the same as the chemical formulas of the starting materials, its a true chemical reaction. Another example is burning methane, better known as natural gas: CH4+2O2 -->CO2+2H20+heat energy Or hydrochloric acid and sodium hydroxide: HCl+NaOH-->NaCl+H2O

Answer 3

Of course. Anything that involves combustion is a reaction, and if you burn your toast a little you are combining the carbohydrate molecules in the toast with oxygen in the air to make CO2 and H2O in the burnt parts.

Answer 4

It is burning the sugars in the bread and turning them into carbon.

Answer 5

Its not.