The answer is yes I believe so.
Melting (solid to liquid)
Answer:
A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.
Explanation:
Hello.
In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:

As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.
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Very good question, I can easily answer that for you if it has 3 moles of ethane contains 6 mole of carbon atoms. so that means 3 moles of ethane contains 18 mole of hydrogen atoms.
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