Molecules of hydrogen escape from earth, but molecules of oxygen and nitrogen are held to the surface and remain in the atmosphere. explain.

Hydrogen is a light molecule

Explanation:

The molecular weight of a gas determines its molecular speed. Hydrogen is a very light gas, far lighter than oxygen or nitrogen. These heavier gases cannot escape the earth because of their molecular weight but hydrogen does escape the earth surface because it is very light molecule having very high molecular speed.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.