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physics and chemistry doubts!!

F

Faiza Anwar

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181
Reaction score
333
Points
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Hello090078601 said:
How to solve:

20 cm^3 of a hydrocarbon was burnt in 175 cm^3 of oxygen. After cooling, the volume of the remaining gases was 125 cm^3. The addition of aqueous sodium hydroxide removed carbon dioxide leaving 25 cm^3 of unreacted oxygen.

i) Volume of oxygen used: ___________

ii) Volume of carbondioxide formed: __________

iii) Deduce the formula of the hydrocarbon and the balanced equation for the reaction.
Click to expand...
volume of oxygen added - volume of unreacted oxygen
i)175 - 25 = 150^cm
volume of remaining gases - volume of oxygen in the remaining gases
ii) 125 - 25 = 100^cm
iii) i couldn't solve this part.
tell me which paper this is i'll check the mark scheme nd then may be i'll understand how to solve it... :)
nd hope this helps..
 
Hello090078601

Hello090078601

Messages
37
Reaction score
45
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8
Faiza Anwar said:
volume of oxygen added - volume of unreacted oxygen
i)175 - 25 = 150^cm
volume of remaining gases - volume of oxygen in the remaining gases
ii) 125 - 25 = 100^cm
iii) i couldn't solve this part.
tell me which paper this is i'll check the mark scheme nd then may be i'll understand how to solve it... :)
nd hope this helps..
Click to expand...

Yeah, hey. I solved the first two as well but for the third one (I checked in the mark scheme) it said any equation for Combustion of Alkene. :/ How come?

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s13_qp_33.pdf ----> The link to the paper.

It's the last question.
 
rida.12.!!

rida.12.!!

Messages
228
Reaction score
529
Points
103
  1. 7 The alcohols form a homologous series. The fi rst member of this series is methanol, CH3OH.
    (ii) The mass of one mole of an r6tis 116 g. What is its formula?
    Show your reasoning.
    ....................................................................................................................................
    .............................................................................................................................. [2]

  2. (b) Methanol is manufactured using the following method.
    CH4(g) + H2O(g) → CO(g) + 3H2(g) reaction 1
    CO(g) + 2H2(g) CH3OH(g) reaction 2
    The conditions for reaction 2 are:
    pressure 100 atmospheres
    catalyst a mixture of copper, zinc oxide and aluminium oxide
    temperature 250 °C
    The forward reaction is exothermic.
    (i) Why is high pressure used in reaction 2?
    ....................................................................................................................................
    .............................................................................................................................. [2]12

    (ii) Explain why using a catalyst at 250 °C is preferred to using a higher temperature of
    350 °C and no catalyst.
    ....................................................................................................................................
    ....................................................................................................................................
    .............................................................................................................................. [3]
    (c) Methanol is oxidised by atmospheric oxygen. This reaction is catalysed by platinum.
    (i) The products of this reaction include a carboxylic acid. Give its name and structural
    formula.
    name .......................................................
    structural formula showing all bonds
    [2]
    (ii) Deduce the name of the ester formed by the reaction of methanol with the carboxylic
    acid named in (i).
    .............................................................................................................................. [1]

  3. electrolysis of :
    }dilute H2SO4
    }aqueous Copper2sulfate​
 
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