Determine the final concentration of 20ml of 5M NaCl of solutions after 30ml of water has been added.
5M x (20/50) = ?? OR if you prefer,
mL x M = mL x M
(Note: Technically, this method works only if we are assuming that the problem says 20 mL 5M NaCl "is added to enough water to make 50 mL of solution" which is another way of saying that the two solutions are additive. Technically, 20 mL of 5M NaCl + 30 mL water may NOT add up to 50 mL.)
To determine the final concentration of the NaCl solution after water has been added, we can use the formula:
C1V1 = C2V2
Where:
C1 = initial concentration of the solution
V1 = initial volume of the solution
C2 = final concentration of the solution
V2 = final volume of the solution
Given that:
C1 = 5M (initial concentration of NaCl)
V1 = 20ml (initial volume of NaCl solution)
V2 = V1 + 30ml (final volume of the solution, including the added water)
Let's substitute these values into the formula and solve for C2:
C1V1 = C2V2
5M * 20ml = C2 * (20ml + 30ml)
100Ml = C2 * 50ml
C2 = 100Ml / 50ml
C2 = 2M
Therefore, the final concentration of the NaCl solution after adding 30ml of water is 2M.