Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    Ok, so im stuck on this particular question which is:

    A solution of phenol in water has a concentration of 38 g dm-3.
    The acid dissociation constant, Ka of phenol is 1.3 x 10-10 mol dm-3.
    Calculate the pH of this solution.

    I hate it the most when the unit of something has gdm-3 or other units thats similar because it really puts me off and I never know what to do.

    So far I have worked out the moles of phenol (n=m/Mr)
    n(Phenol)= 0.404mols
    And I would need to find the concentration, but I don't know the volume. Or is that 1000cm3?

    Please Help, and Thank You
    • Community Assistant
    • Study Helper
    Offline

    17
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Shammy92)
    Ok, so im stuck on this particular question which is:

    A solution of phenol in water has a concentration of 38 g dm-3.
    The acid dissociation constant, Ka of phenol is 1.3 x 10-10 mol dm-3.
    Calculate the pH of this solution.

    I hate it the most when the unit of something has gdm-3 or other units thats similar because it really puts me off and I never know what to do.

    So far I have worked out the moles of phenol (n=m/Mr)
    n(Phenol)= 0.404mols
    And I would need to find the concentration, but I don't know the volume. Or is that 1000cm3?

    Please Help, and Thank You
    You are told the concentration in grams per litre.

    You have converted the grams to moles

    So now you have moles per litre.

    Now you apply the weak acid equilibrium equation to find [H+] and hence pH
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: March 28, 2011
The home of Results and Clearing

2,657

people online now

1,567,000

students helped last year

University open days

  1. Sheffield Hallam University
    City Campus Undergraduate
    Tue, 21 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 22 Aug '18
  3. University of Buckingham
    Postgraduate Open Evening Postgraduate
    Thu, 23 Aug '18
Poll
A-level students - how do you feel about your results?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.