Question

Calculate the molarity of each of the following. 6.25 g of NaCl in 300. mL of a NaCl solution. Express your answer with the appropriate unit

Answer 1

Explanation:

We have to find the molarity of the solution. Molarity is defined like:

Molarity = moles of solute/(volume of solution in L)

Before we calculate the molarity of our solution we will have to convert the volume in mL to L, and the mass of NaCl to moles.

1000 mL = 1 L

Volume of solution = 300. mL * 1 L/(1000 mL)

Volume of solution = 0.300 L

To convert the mass into moles we will use the molar mass of NaCl.

molar mass of Na = 22.99 g/mol

molar mass of Cl = 35.45 g/mol

molar mass of NaCl = 1 * 22.99 g/mol + 1 * 35.45 g/mol

molar mass of NaCl = 58.44 g/mol

moles of NaCl = 6.25 g * 1 mol/(58.44 g)

moles of NaCl = 0.107 moles

Finally we can find the molarity of the solution.

molarity = moles of NaCl/(volume of solution)

molarity = 0.107 moles/(0.300 L)

molarity = 0.357 moles/L

molarity = 0.357 M

Answer: the molartiy of the solution is 0.357 M.