Compare physical change and chemical change in terms of the arrangement of the particles and the changes in number of atoms or types of atoms?

In the reaction between a crushed antacid tablet and vinegar what gas is emitted

Which type of fossil does this image depict?

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