Chem Stoichiometry, questions in Pic

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Which of the following describes a compound? (hint: carbon and oxygen bo a. a piece of pure carbon, containing only carbon atoms b. oxygen gas surrounding a solid piece of carbon c. a substance made of two oxygen atoms for each carbon atom carbon and oxygen atoms mixed without being bonded together

Draw the structure for 5-isopropyl-2-methyl-3-nonene

How will the volume of a gas be affected if the pressure is tripled, but the temperature remains the same?