Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    Its (iv) i dont get but the other parts are needed


    A sample of hydrochloric acid contains 7.05 × 10–3 mol of hydrogen chloride in
    50 cm3 of solution.
    (i) Calculate the concentration, in mol dm–3, of this hydrochloric acid.

    (ii) Write an expression for the term pH.

    (iii) Calculate the pH of this hydrochloric acid.

    (iv) When water is added to this 50 cm3 sample of acid the pH increases. Calculate
    the total volume of the solution when the pH becomes exactly 1.00


    :confused::confused: i know that pH=1 which would mean [H+]= 0.1 but what do you do with that :/
    • TSR Support Team
    Offline

    21
    ReputationRep:
    TSR Support Team
    For iv you need to find the volume of the solution where the concentration is 0.1 moldm-3. You know concentration is related to volume by moles, in the equation n = c * v.

    So, if you know your required concentration, and you're looking for the volume, then the equation rearranges to: v = n/c

    which with this would be: V = n / 0.1.

    So now, calculate the number of moles you've got, and add it to that formula to get the volume, which will be in dm3, then, if necessary convert to cm3 by times by 1000.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Stiff Little Fingers)
    For iv you need to find the volume of the solution where the concentration is 0.1 moldm-3. You know concentration is related to volume by moles, in the equation n = c * v.

    So, if you know your required concentration, and you're looking for the volume, then the equation rearranges to: v = n/c

    which with this would be: V = n / 0.1.

    So now, calculate the number of moles you've got, and add it to that formula to get the volume, which will be in dm3, then, if necessary convert to cm3 by times by 1000.
    Oh yes thanks!
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    What's your favourite Christmas sweets?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

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