Question

what do these two changes have in common?
mixing glue and laundry powder to create putty
using polish to remove tarnish from a silver spoon
select all that apply.
both are changes of state.
both are only physical changes.
both are chemical changes.
both conserve mass.

Explanation:

1. Mixing glue and laundry powder to make putty is a physical change (no new substance formed, just a mixture). Removing tarnish from silver with polish is a chemical change (tarnish reacts with polish to form new substances).
2. Changes of state (like solid to liquid) do not describe either process.
3. The law of conservation of mass applies to all physical and chemical changes—mass is neither created nor destroyed in both processes.
4. They are not both only physical or both only chemical changes.

Answer:

• Both conserve mass.