A buffer is prepared by mixing 200ml of 0.2M salt solution and 400ml of 0.2M acid solution. what's the concentration of the resulting buffer
millimoles salt = mL x M = 200 x 0.2 M = 40
millimoles acid = 400 x 0.2 M = 80
millimoles total = 120
volume total = 600 mL
M = millimoles/ L = 120/600 = 0.2 M
To calculate the concentration of the resulting buffer, we can use the formula:
C1 * V1 = C2 * V2
Where:
C1 = concentration of the salt solution
V1 = volume of the salt solution
C2 = concentration of the resulting buffer (what we want to find)
V2 = total volume of the resulting buffer (sum of the volumes of the salt and acid solutions)
In this case:
C1 = 0.2 M
V1 = 200 ml (0.2 L)
C2 = ?
V2 = 200 ml (0.2 L) + 400 ml (0.4 L) = 600 ml (0.6 L)
Plugging the values in the formula, we have:
0.2 M * 0.2 L = C2 * 0.6 L
Simplifying the equation:
0.04 = 0.6 C2
To solve for C2, divide both sides of the equation by 0.6:
C2 = 0.04 / 0.6
C2 ≈ 0.067 M
Therefore, the concentration of the resulting buffer is approximately 0.067 M.
To find the concentration of the resulting buffer, we need to calculate the number of moles of salt and acid separately, and then combine them to determine the final concentration.
Step 1: Calculate the number of moles of salt (NaCl):
Number of moles of salt = Volume (in liters) × Concentration
Number of moles of salt = 0.2 L × 0.2 mol/L = 0.04 moles
Step 2: Calculate the number of moles of acid (HCl):
Number of moles of acid = Volume (in liters) × Concentration
Number of moles of acid = 0.4 L × 0.2 mol/L = 0.08 moles
Step 3: Combine the number of moles of salt and acid to calculate the concentration of the resulting buffer:
Total number of moles in the buffer = Moles of salt + Moles of acid
Total number of moles in the buffer = 0.04 moles + 0.08 moles = 0.12 moles
Total volume of the resulting buffer = Volume of salt solution + Volume of acid solution
Total volume of the resulting buffer = 200 mL + 400 mL = 600 mL
The concentration of the resulting buffer = Total number of moles / Total volume in liters
The concentration of the resulting buffer = (0.12 moles) / (0.6 L) = 0.2 mol/L
Therefore, the concentration of the resulting buffer is 0.2 mol/L.