Which of these is an element?

a. oxygen

b. sodium chloride

c. water

d. air

What’s the theoretical yield of solid lead

How does kepler second law of planetary motion overthrow one of the basic beliefs of classical astronomy

If you need to add 27.50ml of a solution, which piece of glassware would you use to deliver this volume and explain how you would determine if the 27.50 ml was measured?