It appears you have uploaded a report sheet with data related to a Beer-Lambert Law experiment. To find the exact concentration of the stock solution used for the standard solutions, we would typically use the molar absorptivity, absorbance data, and the dilutions performed to prepare the standard solutions.

Based on the image, there is no direct information provided on the concentration of the stock solution, but the concentrations of the standard solutions are given. To compute or infer the concentration of the stock solution, you may have to check the dilution factors used to prepare the standards or any details in the lab manual or related materials.

Would you like further assistance calculating or reviewing the dilution process, or can you provide more details regarding the stock solution preparation?

Let me know if you have any questions! Here are five related questions to help clarify things:

1. Did you dilute the stock solution to prepare your standard solutions?
2. What is the concentration of each standard solution based on the dilutions?
3. Do you have the total volume used when preparing each standard solution?
4. What was the concentration and volume of the stock solution used during the experiment?
5. Would you like help with calculating the concentration of tartrazine in the unknown sample using Beer's Law?

Tip: When working with Beer-Lambert Law, always keep track of units (Molarity, path length, and absorptivity) to ensure consistency across calculations.