Q19 E - Chemistry (OpenStax)

Question

How are the molecules in oxygen gas, the molecules in hydrogen gas, and water molecules similar? How do they differ?

Step-by-Step Solution

Answer

The molecules in oxygen gas, the molecules in hydrogen gas, and water molecules that all are made up of one or more similar and dissimilar atoms.

 

The molecules of all the species have different numbers of atoms. Oxygen, hydrogen consists of two in order to form the molecule. Water has three atoms. The difference is regarding the bond structure which indicates that oxygen has a double bond whereas the other two molecules have single bonds.

Defining the molecular structure of the molecules

Oxygen and Hydrogen are diatomic molecules with identical atoms while water triatomic with different atoms.

Hydrogen gas has two hydrogen atoms linked together to form an H₂ molecule. The molecule is nonpolar. Oxygen has the structure as the hydrogen. 

In water, two hydrogen atoms replace one oxygen atom with oxygen being the central atom of high electronegative, which means the dipole moment is non-zero, and towards the oxygen atom. Hence, water is a polar molecule.

Defining the similarities between the molecules of oxygen, hydrogen and water

We know that oxygen and hydrogen are present in gaseous states. In the case of water, it is generally in liquid state at room temperature but the water can exist in three states. 

Water exists as water vapour in gaseous state, Liquid water in liquid state and ice in the solid state.

The state of the molecules depends upon the pressure and temperature.