How many atoms are in 5.31 mol of Iron?

Chemistry worksheet - i am not sure what they are asking for exactly?

The picture represents the process that produces most of the energy used by living organisms on earth. which process is represented in the picture? a) the magnetic attraction between two hydrogen nuclei. b) the fusion of hydrogen nuclei to produce a helium nucleus in the core of the sun. c) the fission of hydrogen nuclei to produce a helium nucleus in the core of the sun. d) the chemical reaction between hydrogen nuclei to produce a helium nucleus in earth's atmosphere.

Ajar contains a certain substance. which observation would show that the substance must be either a solid or a liquid?