Question

You are comparing a reaction that produces a chemical change and one that produces a physical change. What evidence could you use to determine which type of change is occurring?

Answer 1

Answer:

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding. Often, physical changes can be undone, if energy is input.

Answer 2

Evidence to determine type of changes is as follows -

• Change in mass is indicative of chemical reaction.
• If a new substance is formed, which can not be changed back to its original form, this product confirms the change to be chemical in nature. Here, new chemical bond formation must have taken place.
• Chemical changes can also be accompanied with energy loss in the form heat, light or sound.