What is the mass of 74.6% of chlorine

The excretory system,need answers for all: )

How many moles of sulfur dioxide are produced when 4.38 moles of oxygen completely react with iron (iv) sulfide

Harry lives in a city, and he has a lung condition known as asthma. on certain days, harry has to stay inside because pollutants in the air make it difficult for him to breathe. which of these pollution sources are nonpoint sources that might bother harry if he goes outside? choose the two that apply.