Question

Which of the following is correct with respect to the chemical formula of $H_{2}O$?

• A. A molecule contains two atoms of H and one atom of O.
• B. The ratio of the mass of H to the mass of O in the molecule is 2:1.
• C. There are twice as many O atoms in the molecule as there are H atoms.
• D. The ratio of the mass of H to the mass of O in the molecule is 1:2.

Answer 1

The correct option is A A molecule contains two atoms of H and one atom of O.

• A chemical formula is a symbolic expression signifying the number of atoms present in a molecular substance. The number of atoms is determined by the subscript attached to the symbol.
• One molecule of $H_{2}O$ has two atoms of hydrogen and one atom of oxygen.
• Hydrogen and oxygen combine in 2(1):16 or 1:8 ratio by mass.