Question

Arrange the following samples in order of increasing number of oxygen atoms:

1 mol H (lower) 2 then O
1 mol CO (lower)2
3x10^23 molecules O (lower)

Answer 1

To determine the number of oxygen atoms in each sample, we can use the chemical formulas and Avogadro's number.

- 1 mol H2O: 2 atoms of hydrogen and 1 atom of oxygen per molecule, so 1 mol contains 2 mol of hydrogen atoms and 1 mol of oxygen atoms, or 1 x 6.022 x 10^23 atoms = 6.022 x 10^23 atoms of oxygen
- 1 mol CO2: 1 atom of carbon and 2 atoms of oxygen per molecule, so 1 mol contains 2 mol of oxygen atoms, or 2 x 6.022 x 10^23 atoms = 1.2044 x 10^24 atoms of oxygen
- 3x10^23 molecules O2: 2 atoms of oxygen per molecule, so 3x10^23 molecules contain 2 x 3 x 10^23 atoms = 6 x 10^23 atoms of oxygen

Therefore, the samples in order of increasing number of oxygen atoms are:
1 mol H2O < 3x10^23 molecules O2 < 1 mol CO2