B. What chemist finds
out how much nitrogen is in a sample of air

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

Which factor is likely to impact the possible number of compounds? presence of unlimited number of elements in the periodic table the inability of atoms to align perfectly with other atoms the ability of all elements to react with every other element all elements being equally reactive

What mass of ca(oh)2 is needed to make 1250ml of a .75m solution?