Final answer:
To prepare a liter of a 2000mcg/100ml solution from a 5g/100ml stock solution, you need to dilute the stock solution with water. The volume of the stock solution needed is 40ml.
Step-by-step explanation:
To prepare a liter of 2000mcg/100ml solution from a 5g/100ml stock solution, you need to dilute the stock solution with water. The concentration of the diluted solution can be calculated using the formula:
C1V1 = C2V2
Where C1 and V1 are the concentration and volume of the stock solution, and C2 and V2 are the concentration and volume of the diluted solution you want to prepare
In this case, the concentration of the stock solution is 5g/100ml. Let's calculate the volume of the stock solution needed to prepare a liter of the diluted solution
C1V1 = C2V2
(5g/100ml)V1 = (2000mcg/100ml)(1000ml
V1 = (2000mcg/100ml)(1000ml)/(5g/100ml)
V1 = 40m
Therefore, you need to mix 40ml of the stock solution with 960ml of water to prepare a liter of the 2000mcg/100ml solution.