Is heating iron to red hot a physical or a chemical change? Explain your answer.

Heating iron to red hot is a physical change. Here's why:

1. Definition: A physical change is a type of change in which the form of matter is altered but one substance is not transformed into another. A chemical change, on the other hand, is a process where one or more substances are altered into one or more new and different substances.

2. No New Substance Formed: When iron is heated until it is red hot, no new substance is formed. The iron remains iron; it just changes its state from solid to liquid.

3. Reversible Change: The process is reversible. If the heat is removed, the iron will cool and return to its original state. This is a characteristic of physical changes.

4. No Change in Chemical Composition: The chemical composition of the iron does not change when it is heated. It remains Fe (the chemical symbol for iron).

Therefore, heating iron to red hot is a physical change, not a chemical change.