If a 20mL sample of milk has a 0.027M concentration of lactic acid, what would the pH be? what would the concentration and pH be in one litre?

To find the pH of a solution with a known concentration of lactic acid, you need to consider the dissociation of lactic acid in water. Lactic acid is a weak acid and partially dissociates into its ions: lactate anions (C3H5O3-) and hydrogen ions (H+).

Step 1: Calculate the concentration of hydrogen ions (H+) from the concentration of lactic acid (C3H6O3).
Lactic acid (C3H6O3) dissociates as follows: C3H6O3 ⇌ C3H5O3- + H+
For every one mol of lactic acid, one mol of H+ is produced.
Since the concentration of lactic acid is given as 0.027 M, the concentration of hydrogen ions (H+) is also 0.027 M.

Step 2: Calculate the pH using the concentration of hydrogen ions (H+).
pH is a logarithmic scale that measures the acidity or basicity of a solution based on the concentration of hydrogen ions (H+). The formula for pH is pH = -log[H+].
Using the concentration of hydrogen ions (H+) from Step 1 (0.027 M), we can calculate the pH: pH = -log(0.027).
Using a calculator, the pH of the 20 mL sample can be calculated as pH ≈ 1.57.

To find the concentration and pH in one liter (1000 mL):
Since the concentration of lactic acid is given in a 20 mL sample (0.027 M), we can use this information to determine the concentration in 1 liter (1000 mL) using the formula:
C1V1 = C2V2,
where C1 is the concentration of the 20 mL sample, V1 is the volume of the 20 mL sample (20 mL), C2 is the desired concentration, and V2 is the desired volume (1000 mL).
Plugging in the known values, we have:
(0.027 M) × (20 mL) = C2 × (1000 mL).
Simplifying the equation, we get:
C2 = (0.027 M) × (20 mL) / (1000 mL).
Using the calculator, the concentration in 1 liter is approximately 0.54 M.

To find the pH in one liter, you can repeat the same steps as for the 20 mL sample:
Step 1: The concentration of hydrogen ions (H+) is the same as the concentration of lactic acid (0.54 M).
Step 2: Calculate the pH using the concentration of hydrogen ions (H+):
pH = -log(0.54).
Using a calculator, the pH in one liter can be calculated.