contestada

calculate the molarity of MgCl2 in the following solution: 5.34 g of MgCl2 is dissolved and diluted to 214 mL of solution.

Respuesta :

Ⲁⲛ⳽ⲱⲉⲅ:

[tex] \quad\hookrightarrow\quad \sf {0.262M }[/tex]

Ⲋⲟⳑⳙⲧⳕⲟⲛ :

Molarity is used to measure the concentration of a solution , so it is also as molar concentration. It is denoted as M or Mol/L

We are given that :

  • Weight of [tex]\sf MgCl_{2} [/tex] = 5.34g
  • Volume of solution = 214 ml , or 0.214 L

The molar mass of magnesium chloride ( [tex] \sf MgCl_{2}[/tex] ) is 95.21 g / mol

We can calculate the molarity of the solution by dividing the number of moles of solute by volume of solvent in liter ,i.e:

[tex] \quad\longrightarrow\quad \sf {M = \dfrac{n}{V} }[/tex] ‎ㅤ‎ㅤ‎ㅤ⸻( 1 )

Where,

  • M = molarity
  • n = number of moles
  • V = Volume

We can calculate the number of moles by dividing the actual mass by its molar mass ,i.e:

[tex] \quad\longrightarrow\quad \sf { n = \dfrac{w}{m}}[/tex]‎ㅤ‎ㅤ‎ㅤ‎ ( 2 )

Where,

  • n = number of moles
  • m = molar mass
  • w = actual mass

Therefore,

[tex] \implies\quad \tt {n =\dfrac{w}{m} }[/tex]

[tex] \implies\quad \tt { n =\dfrac{5.35\: g}{95.21\: g /mol}}[/tex]

[tex] \implies\quad{\pmb{ \tt {n = 0.056 mol}} }[/tex]

Putting the values in equation ( 1 ):

[tex] \implies\quad \tt {M=\dfrac{n}{V} }[/tex]

[tex] \implies\quad \tt { M =\dfrac{0.056\:mol}{0.214\:L}}[/tex]

[tex] \implies\quad\underline{\pmb{ \tt { M = 0.262 \:M }}}[/tex]