Calculate the pH of 10.00 mL of 0.40 mol/L of hydrochloric acid.
pH = -log (H^+)
HCl ionizes 100% so it is 0.4M. Substitute into the pH equation and solve.
i did that, but the answer is wrong.
What did you get. SHOW YOUR WORK. That way I can find the error.
Your answer should have been 0.397 which I would round to 0.4 as a pH. By the way, the 10.00 mL has nothing to do with it (the concn is what counts) UNLESS the 10.00 mL was diluted to some final volume. But the problem does not say that.
oh ok! i wasn't rounding, thank you.
To calculate the pH of a hydrochloric acid solution, you need to use the formula for pH, which is defined as the negative logarithm of the concentration of H+ ions in the solution.
In this case, you are given the volume and concentration of the hydrochloric acid solution. To find the number of moles of H+ ions, you need to multiply the volume (in liters) by the concentration (in moles per liter):
moles of H+ ions = volume (in liters) * concentration (in mol/L)
Given:
Volume = 10.00 mL = 10.00/1000 L = 0.010 L (converted to liters)
Concentration = 0.40 mol/L
moles of H+ ions = 0.010 L * 0.40 mol/L = 0.004 mol
Now, to calculate the pH, you need to take the negative logarithm (base 10) of the concentration of H+ ions:
pH = -log[H+]
Since the concentration of H+ ions is 0.004 mol, you can substitute this value into the equation:
pH = -log(0.004)
Using a scientific calculator, plug in the value 0.004 and take the negative logarithm (base 10) to find the pH.
pH ≈ 2.40
Therefore, the pH of a 10.00 mL solution with a concentration of 0.40 mol/L of hydrochloric acid is approximately 2.40.