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

    How do you calculate the mass lost when 0.50 moles of pink cobalt (II) chloride is turned completely into blue cobalt (II) chloride.
    CoCl2 + 2H2O + 4H2O (blue) CoCl2. 6H2O (pink)
    I know that mass = number of moles x relative atomic mass
    Mass = n x Mr
    Mass = 0.50mol x 237.9Mass = 118.95g
    The relative atomic mass of pink cobalt (II) chloride is 237.9.
    How do I go on from this to find the mass lost?

    You can deduce from the equation that for each mole of cobalt chloride you would "lose" 6 moles of water.
    Clearly you would lose 3 moles of water for half a mole of the salt.
    You need the mass of 3 moles of water- this is your answer.
Do you agree with the PM's proposal to cut tuition fees for some courses?

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