In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant. 

[Q]: Water comes into contact with something made of iron. The water combines with carbon dioxide in the air to form carbonic acid. As the acid is formed, the iron starts to dissolve. Some of the water breaks down into hydrogen and oxygen. The free oxygen and dissolved iron bond together. They form iron oxide, which is rust. 
[A]: water ,iron ,carbon dioxide ,carbon acid ,hydrogen ,oxygen ,iron oxide ; rust 


[Q]: The coal is pulverized to a very fine powder. The coal powder is mixed with hot air and blown into the firebox of the boiler. Water pumped through pipes inside the boiler is turned into steam by the heat. The pressure of the steam pushing against a series of giant blades turns the turbine shaft. Turbine shaft is connected to the shaft of the generator. The magnets inside the generator spin within wire coils to produce electricity. 
[A]: coal powder ,water ,steam ,turbine shaft ,magnets ,electricity 


[Q]: Fans blow air onto the evaporator's coils. The refrigerant within the coils absorbs the heat. The refrigerant changes from a liquid to a gas. The compressor compresses the gas, increasing the pressure. The hot, pressurized gas moves to the condenser. The gas condenses in the condenser and becomes a liquid again. Heat is radiated away from the condenser. The cooled liquid is returned to the evaporator. 
[A]:
Air ,Heat ,Refrigerent Liquid ,Refrigerent Gas ,Liquid