The formula of water is \(\mathrm{H}_{2} \mathrm{O}\). Which of the following is indicated by this formula? Explain your answer. a. the mass of hydrogen is twice that of oxygen in each molecule. b. there are two hydrogen atoms and one oxygen atom per water molecule. c. the mass of oxygen is twice that of hydrogen in each molecule. d. there are two oxygen atoms and one hydrogen atom per water molecule.

In the given chemical formula for water, H₂O, H represents hydrogen, and O represents oxygen. The subscript number ₂ after H indicates that there are two hydrogen atoms in a water molecule. There is no subscript number after O, which means that it's just one oxygen atom in a water molecule.

Let's analyze each statement provided: a. The mass of hydrogen is twice that of oxygen in each molecule. The chemical formula H₂O doesn't reflect anything about the mass of hydrogen and oxygen in the molecule. This statement is not correct. b. There are two hydrogen atoms and one oxygen atom per water molecule. We already established that the formula H₂O indicates that there are two hydrogen atoms and one oxygen atom in each molecule. This statement is correct. c. The mass of oxygen is twice that of hydrogen in each molecule. This statement is also incorrect because it doesn't relate to the ratio of hydrogen and oxygen atoms in the molecular formula H₂O. d. There are two oxygen atoms and one hydrogen atom per water molecule. The formula H₂O doesn't indicate two oxygen atoms and one hydrogen atom. The correct proportion is two hydrogen atoms and one oxygen atom. This statement is incorrect.

Based on our analysis of the chemical formula for water, H₂O, and the given statements, the correct answer is: b. There are two hydrogen atoms and one oxygen atom per water molecule.