Pharmacy has 325mL of a 40% solution. 120mL of sterile water is added to this solution to decrease the concentration. How many grams of active ingredient would be in the diluted solution?(just need to know how to set this up please)

No way to tell the number of grams, since we know nothing about the solute.

But in any case, the mass of solute is not changed by adding some water.

To calculate the grams of active ingredient in the diluted solution, we'll need to follow these steps:

Step 1: Calculate the amount of active ingredient in the original 40% solution.
Step 2: Calculate the final volume of the diluted solution.
Step 3: Calculate the concentration of the active ingredient in the diluted solution.
Step 4: Calculate the grams of active ingredient in the diluted solution.

Let's go through each step:

Step 1: Calculate the amount of active ingredient in the original 40% solution.
To do this, we need to multiply the volume of the original solution (325 mL) by the concentration of the active ingredient (40%).

40% of 325 mL = (40/100) * 325 mL = 130 mL

Step 2: Calculate the final volume of the diluted solution.
To find the final volume, add the volume of the original solution (325 mL) to the volume of sterile water added (120 mL).

Final volume = 325 mL + 120 mL = 445 mL

Step 3: Calculate the concentration of the active ingredient in the diluted solution.
Since the sterile water added does not contain any active ingredient, the concentration of the active ingredient will decrease due to dilution. We can calculate the new concentration using the formula:

New concentration = (Amount of active ingredient in original solution) / (Final volume of diluted solution)

New concentration = 130 mL / 445 mL = 0.2921

Step 4: Calculate the grams of active ingredient in the diluted solution.
Now, we know the concentration of the active ingredient in the diluted solution is 0.2921.

To calculate the grams of active ingredient, we need to multiply the concentration by the final volume of the diluted solution.

Grams of active ingredient = 0.2921 * 445 mL = 129.975 grams (rounded to 3 decimal places)

So, there would be approximately 129.975 grams of active ingredient in the diluted solution.