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

    14
    ReputationRep:


    Here, the temperature is kept constant, so we can consider the volume ratio the same as the mole ratio.
    Now I want to know if my method of approach is correct or not.

    Potassium hydroxide absorbs all the CO2, so we had 40 cm^3 of CO2, and therefore, X= 40

    Now we can develop an equation

    total volume - 20 cm^3 = volume of CO2 and H2O
    (10 + 40 + y/4) - 20 = 40 + y/2
    30 + y/4 = 40 + y/2
    -10 = y/4
    -40 = y

    Now we can divide both by 10 to get:
    x=4, y=-4
    Therefore CxHy = C4H4

    Now the problem is that why I got a negative 4?
    Is my approach correct?


    I have actually found a similar question answered somewhere and here is it:


    My question is that why the water volume was not taken into account here? :confused:


    Your responses will be much appreciated
    Attached Images
      
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Daniel Atieh)


    Here, the temperature is kept constant, so we can consider the volume ratio the same as the mole ratio.
    Now I want to know if my method of approach is correct or not.

    Potassium hydroxide absorbs all the CO2, so we had 40 cm^3 of CO2, and therefore, X= 40

    Now we can develop an equation

    total volume - 20 cm^3 = volume of CO2 and H2O
    (10 + 40 + y/4) - 20 = 40 + y/2
    30 + y/4 = 40 + y/2
    -10 = y/4
    -40 = y

    Now we can divide both by 10 to get:
    x=4, y=-4
    Therefore CxHy = C4H4

    Now the problem is that why I got a negative 4?
    Is my approach correct?


    I have actually found a similar question answered somewhere and here is it:


    My question is that why the water volume was not taken into account here? :confused:


    Your responses will be much appreciated
    If you measure things at room temperature the water is a liquid and hence does not have a gas volume ...
    • Thread Starter
    Offline

    14
    ReputationRep:
    (Original post by charco)
    If you measure things at room temperature the water is a liquid and hence does not have a gas volume ...
    Perfectly clear.

    But now this causes more problems to the above method I followed. Is it correct? I accounted for the volume of water/moles of water in my calculation, is that okay?


    Posted from TSR Mobile
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Daniel Atieh)
    Perfectly clear.

    But now this causes more problems to the above method I followed. Is it correct? I accounted for the volume of water/moles of water in my calculation, is that okay?


    Posted from TSR Mobile
    No, it's not ok if the measurements are taken at room temperature. You have to assume that the volume of water(g) is zero...
    • Thread Starter
    Offline

    14
    ReputationRep:
    (Original post by charco)
    No, it's not ok if the measurements are taken at room temperature. You have to assume that the volume of water(g) is zero...
    Charco, I am genuinely thankful to you. Sorry for one more stupid question, but I needed it!
 
 
 
Poll
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...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.