A 4.691 g sample of MgCl2 is dissolved in enough water to give 750. mL of solution. What is the magnesium ion concentration in this solution?
6.52x10^-2
But when the MgCl2 is dissolved it will form MgO which is solid as well as HCl. So some if not all Of the Mg+ ions will have been used to form the MgO precipitate.
Well, I could tell you the magnesium ion concentration, but I'm afraid it might get a little salty.
To find the concentration of magnesium ions in this solution, we need to first calculate the number of moles of MgCl2 and then convert it into a concentration.
Step 1: Calculate the number of moles of MgCl2.
To do this, we can use the formula:
moles = mass / molar mass
The molar mass of MgCl2 can be found by adding the atomic masses of magnesium (Mg) and chlorine (Cl):
molar mass of MgCl2 = atomic mass of Mg + 2 * atomic mass of Cl
The atomic mass of Mg is approximately 24.31 g/mol, and the atomic mass of Cl is approximately 35.45 g/mol.
molar mass of MgCl2 = 24.31 g/mol + 2 * 35.45 g/mol
molar mass of MgCl2 = 95.21 g/mol
Now, we can calculate the number of moles of MgCl2:
moles = 4.691 g / 95.21 g/mol
moles ≈ 0.04927 mol (rounded to 5 decimal places)
Step 2: Calculate the concentration of magnesium ions.
The concentration is typically expressed in moles per liter (mol/L) or millimoles per liter (mmol/L). In this case, we have 750 mL of solution, which is equivalent to 0.750 liters.
concentration = moles / volume
concentration = 0.04927 mol / 0.750 L
concentration ≈ 0.0657 mol/L (rounded to 4 decimal places)
Therefore, the magnesium ion concentration in this solution is approximately 0.0657 mol/L.
Convert 4.691 g MgCl2 to moles. moles = grams/molar mass.
There is 1 Mg ion/molecule MgCl2; therefore, moles Mg = moles MgCl2.
M Mg ion = moles/L = moles from above/0.750 = ??