in 1912, chemist fritz haber developed a process that combined nitrogen from the air with hydrogen at high temperatures and pressures to make ammonia. specifically, the process involved combining one molecule of nitrogen gas (n2) with three molecules of hydrogen gas (h2) to get two molecules of ammonia (nh3). if you write this process in a symbol format, it looks like this:n2 3h2 → 2nh3explain whether this is a chemical or physical change, and why. does it involve elements, compounds, mixtures, or pure substances? also describe how many atoms are involved before and after. what do you notice about the number of atoms?