Describe in detail a way of preparing 500 ml of solution that is 0.02500 M in sodium ions. Start with solid sodium sulfate decahydrate.
You want 0.025 M Na^+.
You want 0.025 mols Na/L.
How many mols do you want? That is M x L = 0.025 M x 0.500L = ? mols.
If you weigh Na2SO4.10H2O you will want 1/2 mols of Na2SO4 (because there are 2 Na^+ in 1 mol of the salt). Then convert mols Na2SO4.10H2O to grams.
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To prepare a 500 ml solution that is 0.02500 M in sodium ions using solid sodium sulfate decahydrate, you need to follow the steps below:
Step 1: Determine the molar mass of sodium sulfate decahydrate.
Sodium sulfate decahydrate has the chemical formula Na2SO4 · 10H2O. The molar mass can be calculated by adding the molar mass of each element in the compound.
Molar mass of Na = 22.99 g/mol
Molar mass of S = 32.07 g/mol
Molar mass of O = 16.00 × 4 g/mol
Molar mass of H = 1.01 × 2 × 10 g/mol
Therefore, the molar mass of sodium sulfate decahydrate is:
(22.99 × 2) + 32.07 + (16.00 × 4) + (1.01 × 2 × 10) = 322.20 g/mol
Step 2: Calculate the mass of sodium sulfate decahydrate required.
To find the mass of sodium sulfate decahydrate needed to make the solution, you will use the equation:
moles = concentration (M) × volume (L)
Moles = 0.02500 mol/L × 0.500 L = 0.0125 mol
Step 3: Calculate the mass of sodium sulfate decahydrate needed using the moles obtained.
mass (g) = moles × molar mass
mass (g) = 0.0125 mol × 322.20 g/mol = 4.0285 g
Step 4: Weigh the solid sodium sulfate decahydrate accurately using a balance. Measure out 4.0285 grams of solid sodium sulfate decahydrate.
Step 5: Dissolve the solid in a suitable container.
Using a beaker or a flask, add distilled water to the container and then carefully add the weighed sodium sulfate decahydrate. Stir or swirl the solution gently until all the solid is fully dissolved.
Step 6: Transfer the solution to a volumetric flask.
Pour the solution into a 500 ml volumetric flask. Ensure all the solution from the container is transferred to the volumetric flask. Rinse the container with distilled water to ensure no solution is left behind and that the final volume in the volumetric flask is precisely 500 ml.
Step 7: Mix and label the solution.
Using a stopper or a cap, securely close the volumetric flask and mix the solution by inverting it several times. Label the flask with the concentration of the solution (0.02500 M in sodium ions), the date of preparation, and any other relevant information.
Now, you have successfully prepared a 500 ml solution that is 0.02500 M in sodium ions using solid sodium sulfate decahydrate.