# Please help with these questions on Molar Concentration!?

1) If 33.7 moles of MgCl₂ is dissolved to make 8.3L of solution, what is the molarity of the solution? Answer: [MgCl₂] = 4.1 M

2) If 275.2g of KMnO₄ is dissolved in to make 0.500 L of solution, what is the molar concentration of the solution? Answer: [KMnO₄] = 3.48 M

3) 205 L of carbon dioxide gas at STP is compressed and then dissolved in 10.0 L of water. What is the molar concentration of the resulting solution? Answer: [CO₂] = 0.915 M

### 1 Answer

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- Uncle MichaelLv 72 months agoFavorite Answer
1)

Molarity = (33.7 mol) / (8.3 L) = 4.1 M

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2)

Molar mass of KMnO₄ = (39.1 + 54.9 + 16.0×4) g/mol = 158.0 g/mol

Molar concentration = (275.2/158.0 mol) / (0.500 L) = 3.48 M

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3)

Molar volume of CO₂ at STP = 22.4 L/mol

Molar concentration = (205/22.4 mol) / (10.0 L) = 0.915 M

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