Relative dating is the process of determining whether an object or event is older or younger than other objects or events. Absolute dating is d<span>etermining the age of an event or object in years. From absolute dating, the real age of the object is obtained which is not present for relative dating. Hope this helps.</span>
We know 1 mole of any atom or molecules contains 
atom or molecules.
1 mole of HBr i.e 81 gm/mol contains atom or molecules.
So, mass of 
molecules is :
Therefore, mass of molecules is 1.21 gm .
Hence, this is the required solution.
Living organisms use atoms from sugar molecules combined with other elements to form lipids and nucleic acids. Lipids are hydrophobic organic compounds composed of carbon and a high ratio of hydrogen to oxygen. Nucleic acids are an acidic polymer of nucleotides found or produced in the cell nucleus.
