To make a 10 mg/L zinc (Zn) stock solution using zinc sulfate heptahydrate and deionized water, you will need to follow these steps:
Determine the desired volume of the stock solution you want to prepare. Let's assume you want to prepare 1 liter (1000 mL) of the solution.
Calculate the mass of zinc sulfate heptahydrate needed to make the desired concentration. Since you want a concentration of 10 mg/L, and the molar mass of zinc sulfate heptahydrate is approximately 287.54 g/mol, you can use the following formula:
Mass (g) = Concentration (mg/L) x Volume (L) / 1000
Mass (g) = 10 mg/L x 1 L / 1000 = 0.01 g
So, you will need 0.01 grams of zinc sulfate heptahydrate.
Weigh 0.01 grams of zinc sulfate heptahydrate accurately using a digital balance.
Dissolve the weighed zinc sulfate heptahydrate in deionized water. To ensure complete dissolution, you can add the solid to a beaker containing a small volume of deionized water, and then gradually add more water while stirring until the solid is fully dissolved.
Transfer the solution to a volumetric flask with a capacity of 1 liter (1000 mL).
Rinse the beaker and any utensils used to dissolve the zinc sulfate heptahydrate with deionized water and add these rinses to the volumetric flask to ensure you transfer all the dissolved zinc sulfate heptahydrate.
Once all the solution is transferred to the volumetric flask, add deionized water to the flask up to the 1-liter mark, ensuring the solution reaches the calibrated mark precisely.
Cap the volumetric flask and mix the solution thoroughly by inverting it several times to ensure uniform distribution.
You have now prepared a 10 mg/L zinc stock solution using zinc sulfate heptahydrate and deionized water. Remember to label the solution appropriately and store it in a suitable container.