How could you distinguish between the gases h2 and no2?

Explanation:

A molecule is defined as a substance which contains chemically bonded same type of elements.

For example, is a molecule and it exists as a gas which is colorless and odorless.  

Hydrogen gas is represented as .

Whereas a compound is defined as a substance which contains chemically bonded different type of elements in a fixed ratio by mass.

For example, is a compound and has a reddish brown color with toxic odor.

Nitrogen dioxide is represented as .

your mom.com . : 0000

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.