Name the four types of bonding and explain them in your own words. Be specific about the location of the valence electrons.

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

How many moles of air are there in a human lung with a volume of 2.4 l at stp? explain your answer

Calculate the number of molecules present in 0.750 mol of mgo.