how much water would you need to add to 20.0 mL of 2.0 M NaCl to make a 0.10 M solution?
try the formula
c1V1 = c2V2
(where c1 is the initial concentration, V1 is the initial volume, c2 is the diluted concentration and V2 is volume you are trying to find)
when you have found V2 - remember V2 is the final volume including the original 20mL - so to work out how much to add you need to subtract the 20mL from V2.
Another way to look at this, is you are diluting it 20 times (2/.1), so add nineteen parts water to one part original solution.
To solve this problem using the formula c1V1 = c2V2, where c1 is the initial concentration, V1 is the initial volume, c2 is the diluted concentration, and V2 is the final volume, follow these steps:
1. Identify the given values:
- c1 = 2.0 M (initial concentration)
- V1 = 20.0 mL (initial volume)
- c2 = 0.10 M (diluted concentration)
2. Plug these values into the formula:
2.0 M x 20.0 mL = 0.10 M x V2
3. Solve for V2:
V2 = (2.0 M x 20.0 mL) / 0.10 M
V2 = 40.0 mL
Note: V2 represents the final volume, including the original 20 mL of the solution.
4. To determine how much water to add, subtract the initial volume (20.0 mL) from V2:
V_water = V2 - V1
V_water = 40.0 mL - 20.0 mL
V_water = 20.0 mL
Therefore, you would need to add 20.0 mL of water to the 20.0 mL of 2.0 M NaCl solution to make a 0.10 M solution.