Final answer:
The molarity of the diluted HCl solution, after adding 8mL of water to 4mL of 5M HCl, is calculated using the dilution equation M1 x V1 = M2 x V2. The final molarity (M2) of the diluted solution is found to be 1.67 M.
Step-by-step explanation:
Calculating the Molarity of a Diluted Solution:
To calculate the molarity (M) of a diluted solution, we can use the dilution equation:
M1 × V1 = M2 × V2
Where M1 is the initial molarity, V1 the initial volume, M2 the final molarity, and V2 the final volume. In this question, you are diluting 4mL of 5M HCl with 8mL of water. The initial volume (V1) of HCl is 4mL, and the final volume (V2) after adding water will be 4mL + 8mL = 12mL or 0.012L.
Now, applying the dilution equation: (5 M) × (0.004 L) = M2 × (0.012 L).
To find the molarity of the diluted solution (M2), divide both sides by 0.012 L: M2 = (5 M × 0.004 L) / 0.012 L
= 1.67 M.
Therefore, the molarity of the diluted HCl solution is 1.67 M. This is a simple way to calculate the concentration of a diluted solution. Additionally, always remember to consider units and use the same ones on both sides of the equation for consistency.