Final answer:
To find the final percentage concentration of the solution, calculate the amount of potassium chloride in the final solution and divide it by the total volume of the final solution, then multiply by 100 to get the percentage concentration. The final percentage concentration of the solution is 14.3%.
Step-by-step explanation:
To find the final percentage concentration of the solution, we need to calculate the amount of potassium chloride in the final solution and divide it by the total volume of the final solution, then multiply by 100 to get the percentage concentration.
First, we need to calculate the amount of potassium chloride in the initial 120 ml solution. Since the solution is 50% potassium chloride, the amount of potassium chloride is 50% of 120 ml, which is 60 ml.
Next, we need to calculate the total volume of the final solution. We are adding 300 ml of sterile water to the initial 120 ml solution, so the total volume is 120 ml + 300 ml = 420 ml.
Finally, we divide the amount of potassium chloride (60 ml) by the total volume of the final solution (420 ml) and multiply by 100 to find the percentage concentration:
Percentage concentration = (60 ml / 420 ml) x 100 = 14.3%