0.641 g AgCl x (1 mole MgCl2/2 moles AgCl) = 0.641 x (95.21/2*143.32) =?? g MgCl2.
% MgCl2 = (g MgCl2/1.5 g sample)*100 = ??
% Mg(NO3)2 = 100 - %MgCl2.
% MgCl2 = (g MgCl2/1.5 g sample)*100 = ??
% Mg(NO3)2 = 100 - %MgCl2.
1. Calculate the moles of silver nitrate (AgNO3) required to precipitate all chloride ions from the magnesium chloride:
Since 1 mole of silver nitrate reacts with 2 moles of chloride ions:
Number of moles of AgNO3 required = 2 × (mass of chloride precipitate formed / molar mass of AgNO3)
= 2 × (0.641 g / 169.87 g/mol)
2. Determine the moles of chloride ions initially present in the mixture using the stoichiometry of the reaction between AgNO3 and MgCl2:
Since 1 mole of silver nitrate reacts with 2 moles of chloride ions, and assuming complete precipitation:
Number of moles of MgCl2 = (Number of moles of AgNO3 required / 2)
3. Calculate the moles of magnesium nitrate (Mg(NO3)2) present:
Subtracting the moles of MgCl2 from the total moles of magnesium ions:
Number of moles of Mg(NO3)2 = (Total moles of magnesium ions - Number of moles of MgCl2)
4. Calculate the mass percent of MgCl2 in the mixture:
Mass percent = (Mass of MgCl2 / Total mass of the mixture) × 100
Now that we have determined the steps to solve the problem, let's calculate the values.
First, we need to find the number of moles of AgNO3 required:
Mass of chloride precipitate formed = 0.641 g
Molar mass of AgNO3 = 169.87 g/mol
Number of moles of AgNO3 required = 2 × (0.641 g / 169.87 g/mol)
Once we have the number of moles of AgNO3 required, we can find the number of moles of MgCl2 and Mg(NO3)2:
Number of moles of MgCl2 = (Number of moles of AgNO3 required / 2)
Total moles of magnesium ions = (Number of moles of MgCl2) + (Number of moles Mg(NO3)2)
Number of moles of Mg(NO3)2 = (Total moles of magnesium ions - Number of moles of MgCl2)
Finally, we can calculate the mass percent of MgCl2:
Mass of MgCl2 = (Number of moles of MgCl2 × Molar mass of MgCl2)
Total mass of the mixture = (Mass of MgCl2 + Mass of Mg(NO3)2)
Mass percent = (Mass of MgCl2 / Total mass of the mixture) × 100
By substituting the calculated values into the equations, we can find the mass percent of magnesium chloride in the mixture.