Hey! Sign in to get help with your study questionsNew here? Join for free to post

A-level Question on Moles (easy ) ?

Announcements Posted on
Last day to win £100 of Amazon vouchers - don't miss out! Take our quick survey to enter 24-10-2016
    • Thread Starter

    b)Iron Oxide (11.16g of iron reacts to form 15.96g of Iron Oxide)

    What is the empirical formula ???

    This is all I managed to get to

    b) First we work out how many moles of Fe = 11.2/55 = 0.2 moles
    Then for Oxygen = 15.96-11.2 = 4.74g/16 = 0.3 moles

    So where do I go from here ... ??

    any help is greatly appreciated.

    kind regards


    Multiply both number of moles by 10 as we want to get them in whole numbers so it will be 2 and 3.

    Divide by the smallest moles
    Fe- 0.2/0.2=1
    O- 0.3/0.2=1.5
    Times by 2 to get whole number
    Fe- 1x2=2
    O- 1.5x2=3

    Empirical formula = Fe2O3

    Basically Fe2O3

    Iron comes in different forms. It can come in fe(III) or fe(II) so to balance out the charges iron is in its III form.
Write a reply…


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: May 9, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Would you rather find

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

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