Answer:
* No precipitate: 
* Precipitate: 
* Precipitate: 
Explanation:
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In this case, since these all are double displacement reactions, in which the cations and anions are exchanged, we can write the resulting chemical reactions as follows:
a. LiOH and NaCl: No precipitate is formed since LiOH and NaOH are both largely soluble in water:

b. BaCl2 and Na3PO4: barium phosphate precipitate is formed because it has a large molar mass which makes it insoluble in water:

c. MgSO4 and KOH: magnesium hydroxide "milky" precipitate is formed because it is not soluble in water:

Moreover, we can relate the solubility of a substance by considering its polarity, molar mass and nature; usually, heavy substances tend to be insoluble in water as well as nonpolar compounds.
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Answer: 5.5
Explanation: Strontium titanate is both much denser (specific gravity 4.88 for natural, 5.13 for synthetic) and much softer (Mohs hardness 5.5 for synthetic, 6–6.5 for natural) than diamond.
You can take two liquids of different densities (how much mass is in a given volume) and pour them into a funnel. An example is oil and water. When the mixture settles, the denser liquid will be at the bottom, and drips through the funnel first. This is a separation that you can just let occur naturally.