Suppose that a newly discovered element called centium has three isotopes that occur in nature. these are centium-200, centium-203, and centium-209. assume that these isotopes occur in equal amounts in nature. what will be the average atomic mass of this element?

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?

When a nucleus absorbs a neutron and then breaks apart, there are many products of the reaction. what is not a product of a nuclear fission reaction

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)