Find concentration of calcium and magnesium ions

Question

You the precipitated calcium and Mg2+ from Same mixture as their oxalate.Their remaining mass of the mixture in to analysis at 500°C was 5mg and at 900°C was 3.9mg. Calculate the masses of Mg2+ and Ca2+ ions mixture.

Answer 1

The mass of the mixture after heating to 500°C is 5mg. The mass of the mixture after heating to 900°C is 3.9mg. This means that 1.1mg of the mixture has been lost due to the decomposition of the oxalates.

The molar mass of magnesium oxalate is 146.04 g/mol. The molar mass of calcium oxalate is 128.09 g/mol. This means that 0.0079 moles of magnesium oxalate and 0.0066 moles of calcium oxalate were present in the original mixture.

The molar mass of magnesium is 24.305 g/mol. The molar mass of calcium is 40.078 g/mol. This means that the mass of magnesium in the mixture is 0.192 mg and the mass of calcium in the mixture is 0.265 mg.

Therefore, the masses of Mg2+ and Ca2+ ions in the mixture are 0.192 mg and 0.265 mg, respectively.

Here is a table summarizing the results:

IonMass (mg)
Mg2+	0.192
Ca2+	0.265