# A level Chemistry

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#1
20cm^3 of gaseous Alkene is exploaded with 150cm^3 of Oxygen. The gases produced occupies 110cm^3 . When these gases were shaken with an aqueous solution of sodium Hydroxide to remove any excess carbon dioxide remaining after the reaction, the final volume was 30cm^ (all volumes were measured at the same temp and pressure, and all water produced in the reaction is assumed to be in the liquid phase)

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4 years ago
#2
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4 years ago
#3
(Original post by Jamesoates)
20cm^3 of gaseous Alkene is exploaded with 150cm^3 of Oxygen. The gases produced occupies 110cm^3 . When these gases were shaken with an aqueous solution of sodium Hydroxide to remove any excess carbon dioxide remaining after the reaction, the final volume was 30cm^ (all volumes were measured at the same temp and pressure, and all water produced in the reaction is assumed to be in the liquid phase)

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I think you've missed off part of the question - it isn't actually asking anything as it is, just stating information. Can you maybe take a picture of the question and post that?
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#4
Write an equation for the reaction of carbon dioxide with sodium hydroxide
Calculate the formula of the alkene
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4 years ago
#5
(Original post by Jamesoates)
Write an equation for the reaction of carbon dioxide with sodium hydroxide
Calculate the formula of the alkene
The first question is simply book-work; you should be able to find the equation in your textbook or revision guide or on the internet and you just need to remember it. Maybe watch this video:

The second question is more tricky. The general reaction scheme for alkene combustion is:
alkene + oxygen -> carbon dioxide + water

The first thing to do in any calculation question is to convert everything into moles. That will give you the ratios of the different compounds and help you to write the balanced chemical equation.

Can you try to calculate the starting number of moles of the alkene and oxygen?
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4 years ago
#6
(Original post by angryunicorn)
You usually should work to 3sf.
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