How many oxygen ATOMS are present in a #75*g# mass of water?

1 Answer
Apr 16, 2016

Answer:

Approx. #70*g# oxygen.

Explanation:

There are #(75*g)/(18.0*g*mol^-1)# #=# #4.17" moles of water"#.

Clearly, if this is the molar quantity of water, it is also the molar quantity of oxygen. Why? Because there is 1 mol of oxygen ATOMS in 1 mol of water. Here I speak of atomic, not molecular, quantities.

So, we simply have to mulitply this molar quantity by the mass of atomic oxygen: #4.17*mol xx15.999*g*mol^-1# #~= 70*g" oxygen"#