What is the difference between naturally occurring elements and man-made elements? How many of each are there?

What volume of a 2.00 m stock solution of naoh is needed to prepare 150. ml of 0.40 m solution?

Which of the following is not a good technique for managing used oil? a) have specific, labeled catch pans available for technicians who are collecting oil b) spills in your shop and any releases on pavement or outside should be poured down a drain c) do not use oil containers for antifreeze or other non-similar fluids d) be prepared for oil spills with the proper absorbents

What shape would a molecule with two bound groups and two lone pairs have?