A solution contains an unknown amount of dissolved magnesium. Addition of 5.34×10−2mol of Na2CO3 causes complete precipitation of all of the magnesium. What mass of magnesium was dissolved in the solution.

Mg^2+ + Na2CO3 ==> MgCO3 + 2Na^+

Convert mols Na2CO3 to mols Mg^2+ using the coefficients in the balanced equation.
mol Na2CO3 x (1 mol Na2CO3/1 mol Mg^2+) = mols Na2CO3 x 1/1 = ?
Then grams Mg = mols Mg x atomic mass Mg.

To find the mass of magnesium dissolved in the solution, we need to determine the molar mass of magnesium and use stoichiometry to relate it to the amount of Na2CO3 that reacts.

Step 1: Find the molar mass of magnesium.
The molar mass of magnesium can be found on the periodic table.
The atomic mass of magnesium (Mg) is approximately 24.31 g/mol.

Step 2: Calculate the moles of magnesium.
We know that 5.34×10^(-2) mol of Na2CO3 reacts with all the magnesium. This means that the same amount of moles of Mg will also react.
Therefore, the moles of magnesium (Mg) is also 5.34×10^(-2) mol.

Step 3: Calculate the mass of magnesium.
To calculate the mass of magnesium, we will use the equation:
Mass = moles × molar mass.
Mass = (5.34×10^(-2) mol) × (24.31 g/mol).

Using a calculator, we get:
Mass = 1.30 g.

Therefore, the mass of magnesium dissolved in the solution is 1.30 grams.

To find the mass of magnesium dissolved in the solution, we need to use the given information about the amount of Na2CO3 added.

First, let's consider the balanced chemical equation for the reaction between magnesium and sodium carbonate (Na2CO3):

Mg + Na2CO3 -> MgCO3 + 2Na

From the equation, we can see that the stoichiometric ratio between magnesium and sodium carbonate is 1:1. This means that for every mole of magnesium carbonate (MgCO3) formed, one mole of magnesium (Mg) is consumed.

Given that 5.34×10^(-2) mol of Na2CO3 completely precipitates all the magnesium, we can conclude that the moles of Mg dissolved in the solution are also 5.34×10^(-2) mol.

Now, to calculate the mass of magnesium, we need to know the molar mass of Mg, which is approximately 24.31 g/mol.

Mass of magnesium = moles of Mg * molar mass of Mg

Mass of magnesium = 5.34×10^(-2) mol * 24.31 g/mol

Mass of magnesium = 1.298 g (rounded to three significant figures)

Therefore, the mass of magnesium dissolved in the solution is approximately 1.298 grams.