Scientists should perform experiment because Without them, things would most likely not be as perfect as they are now. They wouldn't work properly or they would have malfunctions. It is important to perform them because it makes things safer to use and it makes them more appealing because they work good and are not broken.
The answer is N2 + 3H2 yields 2NH3. The oxidation-reduction reaction means that there is electrons transfer during the reaction which means that the valence changed.
