How many grams of potassium carbonate are needed to make 200 mL of a 2.5 M solution? If I want to use 78 grams of isoproponol (C3H8O) in a reaction, how many mL do I need of a 3.4 M solution?

I have two solutions. In the first solution, 1.0 moles of sodium chloride is dissolved to make 1.0 liters of solution. In the second one, 1.0 moles of sodium chloride is added to 1.0 liters of water. Is the molarity of each solution the same? Explain your answer

Please help, thanks!