Question

1. you pick up a ice cream sandwich from the school cafeteria and you stick it in your hoodie pocket so your hands are free to hand the cash over to the cafeteria worker. you run into your chem lab partner on your way to your seat and he tells you your homework is due next period. you forget all about your ice cream... until you pull the plastic full of mush out of your pocket later that afternoon. is this a physical or chemical change? explain your answer.

Explanation:

A physical change is a change in which the substance's form or state changes, but its chemical composition remains the same. In this case, the ice - cream sandwich melting is a physical change. Melting is a phase change from solid to liquid. The chemical composition of the ice - cream (e.g., the types of molecules present in the ice - cream, cookies etc.) does not change. It is just a change in the physical state due to the absorption of heat (from the body temperature when it was in the pocket). There is no new substance formed. For example, if it were a chemical change, there would be a reaction like burning (where new substances like ash, carbon dioxide etc. are formed) or digestion (where complex molecules are broken down into simpler ones through chemical reactions in the body). But here, it is just a change in the physical form (from a solid - like ice - cream sandwich to a melted, mushy state).

Answer:

This is a physical change. The ice - cream sandwich melting is a phase change (solid to liquid) without a change in chemical composition.