1. Convert grams to moles:
* Find the molar mass of Na₂CO₃:
- Na: 22.99 g/mol (x 2 = 45.98 g/mol)
- C: 12.01 g/mol
- O: 16.00 g/mol (x 3 = 48.00 g/mol)
- Total: 45.98 + 12.01 + 48.00 = 105.99 g/mol
* Calculate the moles of Na₂CO₃:
- Moles = mass / molar mass
- Moles = 2.61 g / 105.99 g/mol = 0.0246 mol
2. Convert milliliters to liters:
* 250 mL = 0.250 L
3. Calculate the concentration (Molarity):
* Molarity (M) = moles of solute / liters of solution
* M = 0.0246 mol / 0.250 L = 0.0984 M
Therefore, the concentration of the sodium carbonate solution is 0.0984 M.
