What word is used for the horizontal rows of the periodic table?

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

What metric units would you use to measure the thickness of a key

Rank the four gases (air, exhaled air, gas produced from from decomposition of h2o2, gas from decomposition of nahco3) in order of increasing concentration of co2