Regents Chemistry Exam August 2022
A scientific sampling instrument landed on a comet. Four of the organic compounds detected on the comet are methyl isocyanate, propanone, propanal, and ethanamide. The structural formula for methyl isocyanate is shown below:
76. Identify the element in these four compounds that makes them organic compounds. 
Carbon is an element that must be present in all organic compounds
77 Write the names of the two organic compounds detected on the comet that are isomers of each other. 
Isomers are two molecules with the same formula but different structure. Propanone and propanal both have three carbons, six hydrogens and one oxygen. Tables P and R can be used to determine the number of carbons and functional group. Propanone is a ketone and propanal is an aldehyde. These two molecules have the same formula, C3H6O but different structure.
Answer: Propanone and propanal