1. describe a procedure to separate a mixture of salt, sand, and water.

1.  A filter was used to separate the sand from the salt water solution (The process of decanting was used if a filer was not available).
2.  A Bunsen burner was used to boil away the water from the salt water solution leaving only salt.

I hope this helps.  Let me know if anything is unclear.

High-energy and unstable.

Answerthe half-reaction having the greatest tendency to occur at the anode:     i₂(aq) + 2e⁻  ⇄ 2i⁻  ;   e = +0.53 v======oxidation occurs at the anode. we must therefore find the half-reaction with the greatest tendency to oxidize.the given values of e are reduction potentials (the form of the half-reactions are of reduction).the lower the reduction potential, the higher the potential to oxidize. the half-cell with the lowest reduction potential will have the greatest tendency to oxidize at the anode.the half-reaction having the greatest tendency must be    i₂(aq) + 2e⁻  ⇄ 2i⁻    e = +0.53 vbecause its reduction potential is the lowest out of the three.