For water you could add oil..ex: cooking oil separates form water because water is heavier than oil.
For Magnesium Sulfate you could add Sodium Carbonate..ex: Sodium Carb reacts to Mg Sulfate adding a darker hue to the liquid and adding a lot of bubbles.
For Sodium Carbonate you could add Sulfuric Acid..ex: Sulfuric Acid would add a reaction to the Sodium Carb that would resembling water boiling
H0P3 It H3LPS :)
Answer:
1: due to difference in reactivity and melting point
2 during the reaction both combine with oxygen in this case magnesium remain solid but some potassium vaporise