Considering the definition of molarity, 6.2125 g of Na₂SO₄ is needed to prepare 350 mL of a solution having a sodium ion concentration of 0.125 M.
But first, you have to know that molarity is a measure of the concentration of a solute that is defined as the number of moles of solute that are dissolved in a certain volume.
Molarity is also known as the molar concentration of a solution and it is calculated by dividing the moles of the solute by the volume of the solution:
[tex]molarity=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
In this case, you know that:
Replacing in the definition of molarity:
[tex]0.125 M=\frac{number of moles of solute}{0.350 L}[/tex]
Solving:
number of moles of solute= 0.125 M× 0.350 L
number of moles of solute= 0.04375 moles
Being 142 [tex]\frac{g}{mole}[/tex] the molar mass of Na₂SO₄, that is, the mass of one mole of the compound, the amount of mass that contains 0.04375 moles is calculated as:
mass= 0.04375 moles× 142 [tex]\frac{g}{mole}[/tex]
mass= 6.2125 g
In summary, 6.2125 g of Na₂SO₄ is needed to prepare 350 mL of a solution having a sodium ion concentration of 0.125 M.
Learn more about molarity with this example: brainly.com/question/15406534?referrer=searchResults
