Why does the mixture of Fe and S have different reactions than the compound FeS?

An experimental procedure requires a 10 ml of acid to be dissolved

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?