Since Alai is hitting each with a hammer, the physical property which he must be comparing on the two materials must be hardness. Solubility can be tested when you put them in a solvent. Odor can be tested with smell. Conductivity can be tested with electricity. Hardness can be tested with its resistance to the force that hits it.
Educated Guess Here!
Since Br-80 does not exist, maybe that means Br-79 or Br-81 have very unequal abundances. For example, Br-79 may have 75% abundance whereas Br-81 may have 25% abundance.
The answers would be:
In a solution, the solvent is present in a greater amount.
In a solutions, the solute dissolves in a solvent.
In general, these are the best answers. The solute is what is being dissolved and the solvent is what dissolves. A solvent comes in greater amounts in a solution and it is the dissolving agent.
For example, sugar and water.
To make a sugar water solution, you will need to dissolve sugar in water. Sugar is the solute in this case because it is what is being dissolved. The water is the solvent, because it dissolves the sugar.
If you had more sugar than water, then you cannot make a solution.