Turn on thread page Beta
    • Thread Starter
    Offline

    8
    ReputationRep:
    100 cm3 of methane, CH4, is completely burned in 400 cm3 of oxygen.

    What is the final volume of the gas mixture, in cm3, when all volumes are measured at room temperature and pressure?

    A) 100

    B) 200

    C) 300

    D) 400

    Please somebody give the answer with detailed working. Thanks. God Bless you.
    Offline

    18
    (Original post by dajjal619)
    Please somebody give the answer with detailed working. Thanks. God Bless you.
    No. We won't just give you a full worked solution, it doesn't help you in the long run.

    Start by writing out a balanced chemical equation.

    edit: turns out we will do it for you :facepalm:
    Offline

    10
    ReputationRep:
    (Original post by dajjal619)
    100 cm3 of methane, CH4, is completely burned in 400 cm3 of oxygen.

    What is the final volume of the gas mixture, in cm3, when all volumes are measured at room temperature and pressure?

    A) 100

    B) 200

    C) 300

    D) 400

    Please somebody give the answer with detailed working. Thanks. God Bless you.
    moles of methane = 100/24000
    moles of oxygen = 400/24000
    CH4 + O2 -> CH4O2
    methane is the limiting reagent therefore you use the number of moles of methane found then
    (100/24000) * 24000 = 100
    but then you have 300 O2 spare
    so ....
    Offline

    1
    ReputationRep:
    (Original post by dajjal619)
    100 cm3 of methane, CH4, is completely burned in 400 cm3 of oxygen.

    What is the final volume of the gas mixture, in cm3, when all volumes are measured at room temperature and pressure?

    A) 100

    B) 200

    C) 300

    D) 400

    Please somebody give the answer with detailed working. Thanks. God Bless you.
    Its about the molar ratio. First you need to work out the balanced symbol equation: CH4 + 2O2 --> CO2 + 2H2O

    This means that 1 mol of CH4 will react with 2 mols of oxygen to form 1 mol of carbon dioxide and 2 mols of water.

    So 100cm3 reacts with 200cm3 (as it is a ratio of 1:2) to form 100cm3 of carbon dioxide (we are not interested in the water as it is not a gas)

    However the oxygen is in excess, so the answer is the volume of the excess plus the volume of the carbon dioxide:
    (400-200)+100 =300 the answer is C
    • Thread Starter
    Offline

    8
    ReputationRep:
    Thanks Sir. God Bless you.
    • Thread Starter
    Offline

    8
    ReputationRep:
    Yes sir u r right. Trying from our side is necessary. But believe me i got the answer be4 posting the question, I just wanted to confirm . Thanks for your concern.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: February 24, 2018
Poll
Favourite type of bread

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.