## pH & pOH Calculations Practice

Below you will find a set of problems where you will need to figure out the concentration of H+ and OH- ions, along with the pH and pOH. Only one of these values will be given to you, so use what you learned on the pH & pOH page to help you answer these problems. A scientific calculator has been provided as a resource for you to use along with a sample problem, which carefully explains all the steps. Good luck!

Sample Problem: If the H+ concentration is 0.001 or 10e-3, then what is the OH- concentration, pH and pOH? Whoa, this must seem so hard. But think again, and of what you just learned on the pH & pOH page, and how knowing one value can help you know all the values. In addition, for this specific one, you can use the trick I taught you: if the H+ concentration is in the form: 10e-x, then the pH is x, meaning the pH is 3. The pOH is found by subtracting the pH from 14, which is 14 - 3, so the pOH is 11. Remember, knowing the pOH or pH means you know the other. Next the concentration can be found by using the equation: 2nd log [ -pOH] This gives you 10e-11 for [OH-] |
Okay, let's get started below! Just fill in the missing values and check your work with the answer key, which can be found here. Good luck and be sure to use the scientific calculator above for calculations. Round all answers to two decimal places (hundredths place) and don't make any careless mistakes! |

Problem 1:pH = ? pOH = 7.35 [H+] = ? [OH-] = ? Check Answer Problem 3:pH = 2.86 pOH = ? [H+] = ? [OH-] = ? Check Answer Problem 5:pH = ? pOH = ? [H+] = 7.76e-10 [OH-] = ? Check Answer Problem 7:pH = ? pOH = 10.6 [H+] = ? [OH-] = ? Check Answer Problem 9: If the molarity of HCl is 1.62e-7, fill in the following: pH = ? pOH = ? [H+] = ? [OH-] = ? Check Answer |
Problem 2:pH = ? pOH = ? [H+] = ? [OH-] = 4.47e-12 Check Answer Problem 4:pH = 1.37 pOH = ? [H+] = ? [OH-] = ? Check Answer Problem 6:pH = ? pOH = ? [H+] = ? [OH-] = 1.00e-10 Check Answer Problem 8:pH = ? pOH = ? [H+] = ? [OH-] = 2.51e-4 Check Answer Problem 10:If the molarity of NaOH is 1.82e-10, fill in the following: pH = ? pOH = ? [H+] = ? [OH-] = ? Check Answer |