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A chemist makes up a solution by dissolving 39.0 g of Mg(NO3)2 in enough water to produce a final solution volume of 257 mL. To calculate the molarity of the solution, what additional information is needed

User Chronicle
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1 Answer

7 votes

Answer:


M=1.02M

Step-by-step explanation:

Hello.

In this case, since the molarity of a solution is computed as the moles of solute over volume of solution:


M=(n_(solute))/(V)

Since the volume of the solution is 257 mL or also 0.257 L, we compute the moles of solute, which is magnesium nitrate (molar mass = 148.3 g/mol), as shown below:


n_(solute)=39.0gMg(NO_3)_2*(1molMg(NO_3)_2)/(148.3 gMg(NO_3)_2)=0.263molMg(NO_3)_2

Thus, the required molarity turns out:


M=(0.263molMg(NO_3)_2 )/(0.257L)\\ \\M=1.02M

Best regards.

User Mike Kwan
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