Para preparar una solución acuosa de 80 g al 10% masa-masa de NaCl, ¿cuántos gramos de soluto y solvente se deben de agregar?

Physical because you are not changing the substance. For example water vapor(gas) can be condensed back into water. If you burn a piece of paper the ash cannot be changed back into paper therefore it is chemical. But because you are not changing the substance the answer is physical.