How many water (H2O) molecules could you line up end to end in a nanometer?

Molecules have size and different molecules are different sizes. When talking about the size of a molecule, most scientists will mention its molecular weight. That is the total weight of all of the atoms in the molecule. So water, which is made up of two hydrogen atoms (1 atomic mass unit each) and one oxygen atom (16 atomic mass units) has a molecular weight of 18 (well, 18.01528 to be exact). Glucose has a molecular weight of 180. DNA, which is very long, can have a molecular weight that is around 1010 (about the weight of one human chromosome).

Explanation:

the water is warmed up by the sun and then it evaporates into the atmosphere. the sunlight warms the water by its heat. water is then cooled down and condensation takes place. the water then finally returns back to the earth by the process of precipitation in the form of rain or ice.

explanation: