Hey there! Sign in to join this conversationNew here? Join for free

AS chemistry calculating the Mr of Calcium Hydroxide from a titration. Watch

    • Thread Starter
    Offline

    3
    ReputationRep:
    You are provided with 50.0 cm3 of 0.200 mol dm−3 hydrochloric acid and a standard solution of NaOH and titration equipment and a solid which is believed to be calcium hydroxide. How would you calculate the relative formula mass by means of titration to determine whether this solid is calcium hydroxide. Please help with the calculations and the understanding behind the calculations, thanks.
    Offline

    14
    ReputationRep:
    I wonder if calcium hydroxide is not there present in the titration how would we calculate? Did you want to find the Mr of NaOH?
    Also, is it allowed to measure the mass of the solid?
    • Thread Starter
    Offline

    3
    ReputationRep:
    Hi yes so i went about this question firstly by calculating the mass of calcium hydroxide and found a value of 0.371g this was deduced from the information given about HCl. But however the acid obviously needs to be in excess for the titration to occur so we need less than 0.371g of Calcium Hydroxide. But then i am a little confused aabout how to calculate the number of moles of Calcium Hydroxide, at the start we originally have 5.00x10-3 but then apparently the number of moles of NaOH should be subtracted tfrom this value. I dont understand why this is, since it is the excess HCl that reacts with the NaOH.
    So in summary the bit i am just unsure with is why do we subtract the number of moles of NaOH from the original number of moles of Calcium Hydroxide??
 
 
 
  • 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
    Did TEF Bronze Award affect your UCAS choices?
    Help with your A-levels

    All the essentials

    The adventure begins mug

    Student life: what to expect

    What it's really like going to uni

    Rosette

    Essay expert

    Learn to write like a pro with our ultimate essay guide.

    Uni match

    Uni match

    Our tool will help you find the perfect course for you

    Study planner

    Create a study plan

    Get your head around what you need to do and when with the study planner tool.

    Study planner

    Resources by subject

    Everything from mind maps to class notes.

    Hands typing

    Degrees without fees

    Discover more about degree-level apprenticeships.

    A student doing homework

    Study tips from A* students

    Students who got top grades in their A-levels share their secrets

    Study help links and info

    Can you help? Study help unanswered threadsRules and posting guidelines

    Sponsored content:

    HEAR

    HEAR

    Find out how a Higher Education Achievement Report can help you prove your achievements.

    Groups associated with this forum:

    View associated groups
  • 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.