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Q. Calculate the mass of an O2 molecule?
Answer: Oxygen is a two-atom molecule
Formula to calculate the mass of the molecule
= Molecular weight
Avogadro number
Avogadro number (NA) is ( 6.023 × 1023)
Molecular mass is the total of the masses of the elements in a molecule, which is called molecular weight. To get the molecule’s mass, you add up each element in it, multiply that number by the atomic weight of that element, and divide that number by how many atoms there are in the molecule.
The periodic table is just the ordered set of atoms that are found in nature. It is arranged in groups and periods based on the number of atoms in each group. It tells you how many atoms there are in it and how many of each type there are. There are 16.00 amu in the mass of one oxygen atom because of this periodic table.
16 amu is the mass of an oxygen atom,
Therefore
32 amu is the mass of an O2 molecular,
Mass of one molecule of oxygen
32/NA( 6.023 × 1023)
5.31 × 10-23g
Remember that the molecular mass is the mass of the Avogadro number of molecules, and the mass of a molecule is just the mass of a single molecule which is also its actual mass. Do not confuse these two things. This is the number of atoms of O2 in an atomic mass unit: 32 amu.
