Sodium carbonate (Na2CO3) has a molar weight of 105.9885 g/mol. A solution contains 50. mM sodium ions and 25 mM carbonate ions. What is the concentration of sodium carbonate in the solutions as expressed as mass/volume percentage?
grams Na^+ = mols Na^+ x molar atomic mass Na^+.
Then % Na^+ = (g Na^+/100 mL) = ?
Carbonate is done similarly.
To determine the concentration of sodium carbonate (Na2CO3) in the solution as mass/volume percentage, you need to calculate the mass of Na2CO3 in the given solution and then express it as a percentage in terms of the solution volume.
First, let's calculate the molarity of Na2CO3 in the solution.
Molarity (M) is defined as the number of moles of solute per liter of solution.
Given the molar weight of Na2CO3 is 105.9885 g/mol, we can calculate the molarity of Na2CO3 using the formula:
Molarity (M) = moles of solute / volume of solution (in liters)
Since the solution contains 50 mM (millimolar) of sodium ions, this means there are 50 mmol of sodium ions in 1 liter of solution.
The molecular weight of sodium ion (Na+) is approximately 22.98977 g/mol. Therefore, 50 mmol of sodium ions is equivalent to:
mass of sodium ions = molar weight of sodium ion × moles of sodium ions
mass of sodium ions = 22.98977 g/mol × 50 mmol
mass of sodium ions = 1144.4885 g
Similarly, the solution contains 25 mM of carbonate ions. The molecular weight of carbonate ion (CO3^2-) is approximately 60.00928 g/mol. Thus, 25 mmol of carbonate ions is equivalent to:
mass of carbonate ions = molar weight of carbonate ion × moles of carbonate ions
mass of carbonate ions = 60.00928 g/mol × 25 mmol
mass of carbonate ions = 1500.232 g
Now, let's calculate the mass of Na2CO3 in the solution by summing the mass of the sodium ions and carbonate ions:
mass of Na2CO3 = mass of sodium ions + mass of carbonate ions
mass of Na2CO3 = 1144.4885 g + 1500.232 g
mass of Na2CO3 = 2644.7205 g
Finally, to calculate the mass/volume percentage of Na2CO3 in the solution, divide the mass of Na2CO3 by the volume of the solution and multiply by 100:
% mass/volume = (mass of Na2CO3 / volume of solution) × 100
However, the volume of the solution is not provided in the question. Therefore, unless the volume is specified, it is not possible to calculate the mass/volume percentage of Na2CO3 in the solution.