A series of standard solutions of benzene in toluene solvent is to be prepared for an internal standard procedure with ethylbenzene serving as the internal standard. Tell how you would prepare the solutions, including the milliliters of benzene concentrations are to be 0.5%, 1.0%, 2.0%, and 3.0% and the internal standard concentration is to 1.0%.
To prepare the series of standard solutions of benzene in toluene solvent with ethylbenzene as the internal standard, follow these steps:
1. Determine the total volume of each solution you want to prepare. Let's assume you want to prepare 100 mL of each solution.
2. Calculate the volume of benzene needed for each concentration by using the desired percentage concentration and the total volume of the solution. Let's calculate the volumes for each concentration:
- For a 0.5% benzene solution: 0.5% of 100 mL = 0.5 mL of benzene
- For a 1.0% benzene solution: 1.0% of 100 mL = 1 mL of benzene
- For a 2.0% benzene solution: 2.0% of 100 mL = 2 mL of benzene
- For a 3.0% benzene solution: 3.0% of 100 mL = 3 mL of benzene
Note: Since the desired concentration is in percentage (%), the volume will be a percentage of the total volume of the solution.
3. For the internal standard solution with ethylbenzene, prepare a 1.0% solution. Since we want to prepare 100 mL of solution, the volume of ethylbenzene needed will be 1.0 mL.
4. Measure the required volume of toluene solvent for each solution. This will be the remaining volume after adding benzene or ethylbenzene. Using the information above:
- For a 0.5% benzene solution: 100 mL - 0.5 mL = 99.5 mL of toluene
- For a 1.0% benzene solution: 100 mL - 1 mL = 99 mL of toluene
- For a 2.0% benzene solution: 100 mL - 2 mL = 98 mL of toluene
- For a 3.0% benzene solution: 100 mL - 3 mL = 97 mL of toluene
- For the internal standard solution: 100 mL - 1 mL = 99 mL of toluene
5. Measure the calculated volumes of benzene or ethylbenzene and the volumes of toluene separately using graduated cylinders or volumetric flasks.
6. Add the measured volumes of benzene or ethylbenzene to separate containers (such as vials or flasks) containing the respective volumes of toluene.
7. Mix each solution well to ensure homogeneity.
8. Label each solution with the corresponding benzene or ethylbenzene concentration.
By following these steps, you can prepare a series of standard solutions of benzene in toluene solvent with the desired concentrations.