why do you think the half-life of a first order reaction is not dependent on the initial concentration of the reactant, but the half-life of a second order reaction is dependent on the initial concentration of the reactants.

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?