Taking into account the definition of molarity and ppm, if the molarity of a 50 mL Fe²⁺ solution is 6.53*10⁻⁵ M, the concentration in ppm is 5.846×10⁻⁵.
First of all, you have to know that molarity is a measure of the concentration of a substance that indicates the number of moles of solute that are dissolved in a given volume.
Molarity is determined by:
[tex]Molarity=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
On the other hand, ppm is a concentration unit used for very dilute solutions. A solution with a concentration of 1 ppm contains 1 gram of solute per million (10⁶) grams of solution, or equivalently, 1 mg of solute per kilogram of solution.
Since these dilute aqueous solutions have densities of 1 g/mL = 1 kg/L, 1 ppm also corresponds to 1 mg of solute per liter of solution.
Then, knowing the molarity of the solution, which is expressed in [tex]\frac{moles}{liter}[/tex], it is necessary to find the concentration expressed in [tex]\frac{mg}{liter}[/tex]. To do this, you must first know the number of moles present in 50 mL. For that, you replace the value of the molar concentration and the volume in the definition of molarity as follows, where 50 mL=0.05 L (being 1000 mL= 1 L):
[tex]6.53x10^{-5} \frac{mole}{liter} =\frac{number of moles of solute}{0.05 L}[/tex]
Solving:
number of moles= 6.53×10⁻⁵[tex]\frac{moles}{liter}[/tex] *0.05 L
number of moles= 3.265×10⁻⁶ moles
Being the atomic mass of Fe 55.85, then the mass containing 3.265×10⁻⁶ moles moles of Fe is calculated by:
[tex]mass=3.265x10^{-6} molesx\frac{55.85 grams}{1 mole}[/tex]
mass=5.846×10⁻⁸ grams
Being 1 grams equals to 1000 mg, then 5.846×10⁻⁸ grams is equal to 5.846×10⁻⁵ mg.
Then in 1 L of solution there is present 5.846×10⁻⁵ mg of Fe²⁺.
Remembering that in dilute solutions 1 ppm = 1 mg/L, if the molarity of a 50 mL Fe²⁺ solution is 6.53*10⁻⁵ M, the concentration in ppm is 5.846×10⁻⁵.
Learn more about molarity with this example: brainly.com/question/15406534?referrer=searchResults
