Answer:C
Explanation: The mass is still the same even though they took it apart.
Answer: 175.35g
Explanation: A 3 M solution has 3 moles of solute per litre.
The mass of one mole of NaCl equals the MW of NaCl MW = 35.45 + 23 =58.45 g/mol
The mass of 3 moles is 58.45 g/mol ×3 mol=175.35 g NaCl or 200 g rounded to one sigfig.
I think you want to ask the complete ionic equation and net ionic equation. For complete ionic equation: 3Ba2+ + 6Cl- + 2Al3+ + 3SO42- -->3BaSO4 + 2Al3+ + 6Cl-. For net ionic equation: 3Ba2+ + 3SO42- -->3BaSO4.
Answer : The molar solubility of
is 
Explanation :
The solubility equilibrium reaction will be:

The expression for solubility constant for this reaction will be,
Let the molar solubility be, 'x'

Now put all the given values in this expression, we get:


Therefore, the molar solubility of
is 
You will know when the solid has formed a solution with water when you can't see any part of the solid left.