How To Calculate Atoms?

First you need to know the molecular formula for the molecule. Lets use water, H2O.
H has an atomic mass of 1, so H2 = 2
O has atomic mass of 16
16+2=18, which is the relative atomic mass of 1 water molecule (relative to a carbon 12 atom).
We must also know the mass of water, lets say 50g.
We can find the number of moles of water using the equation:
Number of moles = mass/mass of 1 mole
number of moles = 50/18 = 2.77777777777moles

Each mole of any substance contains 6.022x1023 molecules. So if we multiply 2.77777 by this number (avogadro's constant) then we get the number of molecules, =1.6727777x102
Now, since there are 3 atoms present in each water (2 hydrogen, 1 oxygen), we can find the total number of atoms by multiplying this answer by 3, = 5.018333x1024
If you mean the number of atoms in a single molecule, then you just need to know the molecular formula. I was assuming you meant for an amount of the molecule.
thanked the writer.

my name is bob i am the best

First you need to know the molecular formula for the molecule. Lets use water, H2O.
H has an atomic mass of 1, so H= 2
O has atomic mass of 16
16+2=18, which is the relative atomic mass of 1 water molecule (relative to a carbon 12 atom).
We must also know the mass of water, lets say 50g.
We can find the number of moles of water using the equation:
Number of moles = mass/mass of 1 mole
number of moles = 50/18 = 2.77777777777moles

Each mole of any substance contains 6.022x1023 molecules. So if we multiply 2.77777 by this number (avogadro's constant) then we get the number of molecules, =1.6727777x102
Now, since there are 3 atoms present in each water (2 hydrogen, 1 oxygen), we can find the total number of atoms by multiplying this answer by 3, = 5.018333x1024
If you mean the number of atoms in a single molecule, then you just need to know the molecular formula. I was assuming you meant for an amount of the molecule.

thanked the writer.
H2o
thanked the writer.
bob rich commented
are you ok
Anonymous commented
You just copied this from the guy above, BITCH!!! 