An iron fence is left on painted and it reacts with the oxygen in the air form forming rust. the formation of the rest is an oxidation-reduction reaction but it is also an example of a reaction (1 point)
8. cooking requires continuous addition of energy to the chemical reactions the are taking place the chemical reaction involved in cooking can be described (1 point)
9. measuring how quickly a reactanat disappears in one way to measure the the reaction

An iron fence is left on painted and it reacts with the oxygen in the air form forming rust. the formation of the rest is an oxidation-reduction reaction but it is also an example of a double-displacement reaction. 

cooking requires continuous addition of energy to the chemical reactions the are taking place the chemical reaction involved in cooking can be described as a chemical change.

measuring how quickly a reactanat disappears in one way to measure the rate of the reaction

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.