Hi! I'm looking for some help with this practice question from Margaret's Step-Up, I had to leave early and missed the explanation:
What is the pH of 0.20M CH3NH3Cl (aq) given that CH3NH2, Kb=3.6x10^-4?
I'm not sure where to start. Thank you!
Practice Question
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Alyssa Cheung 3I
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Re: Practice Question
I think this should be the general idea of what you're going for:
1. Write the chemical equation.
2. Create your ICE table.
3. Write out the equilibrium constant formula for Kb.
4. Plug in your values/variables from the ICE table into the Kb formula. Remember that Kb was already given in the question, so you're only solving for x right now.
5. Isolate/solve for x.
6. Your ICE table should have an equilibrium concentration value for [OH-]. Apply x to that value, and you just solved for the numerical value of [OH-].
7. Calculate pOH by using the -log[OH-] formula.
8. Use the rule pOH+pH=14 to isolate/solve for pH.
1. Write the chemical equation.
2. Create your ICE table.
3. Write out the equilibrium constant formula for Kb.
4. Plug in your values/variables from the ICE table into the Kb formula. Remember that Kb was already given in the question, so you're only solving for x right now.
5. Isolate/solve for x.
6. Your ICE table should have an equilibrium concentration value for [OH-]. Apply x to that value, and you just solved for the numerical value of [OH-].
7. Calculate pOH by using the -log[OH-] formula.
8. Use the rule pOH+pH=14 to isolate/solve for pH.
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