Question

what do these two changes have in common? water boiling on a stove using a large magnet to remove pieces of iron from a junkyard select all that apply. both are only physical changes. both are chemical changes. both are caused by heating. both are caused by cooling.

Explanation:

• Water boiling on a stove: This is a physical change. When water boils, it changes from liquid to gas (steam). The chemical composition of water ($H_2O$) remains the same. There is no new substance formed. It is caused by heating.
• Using a large magnet to remove pieces of iron from a junkyard: This is also a physical change. The magnet attracts iron based on its magnetic properties. There is no chemical reaction (no new substances are formed). And it is not caused by heating or cooling.

Answer:

A. Both are only physical changes.