Answer:
The answers to your questions are below
Step-by-step explanation:
Physical change is when matter changes its form but is still the same substance.
Chemical change is when matter changes its composition.
iron and oxygen from rust It's a chemical change because iron and oxygen form a new compound different from the reactants.
iron is denser brightly when ignited . This is a chemical property because iron reacts with oxygen.
oil and water do not mix it's a physical change, oil and water are in touch but they do not react.
mercury melts at -39°C it's a physical property because mercury changes from solid to liquid but it still is mercury.