A 4.379 g sample of MgCl2 is dissolved in enough water to give 750.0 mL of solution. What is the chloride ion concentration in this solution?
mols MgCl2 = grams/molar mass = ?
M MgCl2 = mols/L solution = ?
Since there are two mols Cl in 1 mol MgCl2, then M Cl = twice that of MgCl2.
To find the chloride ion concentration in the solution, we can use the concept of molarity. Molarity is defined as moles of solute divided by the volume of the solution in liters.
First, let's calculate the number of moles of MgCl2 using its molar mass. The molar mass of MgCl2 is the sum of the atomic masses of magnesium (Mg) and two chloride ions (Cl):
Mg (atomic mass) = 24.305 g/mol
Cl (atomic mass) = 35.453 g/mol
Molar mass of MgCl2 = 24.305 g/mol + 2 * 35.453 g/mol = 95.211 g/mol
Now, we can calculate the number of moles of MgCl2 in the 4.379 g sample:
moles of MgCl2 = mass of MgCl2 / molar mass of MgCl2 = 4.379 g / 95.211 g/mol
Next, we convert the volume of the solution from milliliters (mL) to liters (L):
volume of solution = 750.0 mL = 750.0 mL / 1000 mL/L = 0.750 L
Finally, we can calculate the chloride ion concentration (in Molarity) in the solution by dividing the moles of MgCl2 by the volume of the solution in liters:
chloride ion concentration = moles of MgCl2 / volume of solution
Substituting the values, we get:
chloride ion concentration = (4.379 g / 95.211 g/mol) / 0.750 L
Now, you can calculate the chloride ion concentration using a calculator or solve the given expression to get the final answer.