Year 12s: what will be the first way you research your future options? >>

...reacts completely with hydrogen.

Write an equation for the reaction where isoprene (C5 H8) reacts completely with hydrogen.

I got C5 H8 + H2 >> C5 H10

But mark scheme reads C5 H8 + 2H2 >> C5 H12

I understand that they'vde balanced the equation. But was it not balanced before? :s

Reply 1

FoOtYdUdE

oh is it because the double bonds have broken (COMPLETELY) therefore the product is an ALKANE? Gen formula for alkane = cn h2n+2 aaah, i think i've got it. :smile:

Reply 2

shengoc

FoOtYdUdE

oh is it because the double bonds have broken (COMPLETELY) therefore the product is an ALKANE? Gen formula for alkane = cn h2n+2 aaah, i think i've got it. :smile:

Yes, hydrogenation to an alkene gives you an alkane, with the general formula 2n+2.

Reply 3

ashbawa

You need a h2 for every double bond present to completely hydrogenate the alkene therefore in this case you require 2h2 as there are two double bonds in order to form the correct product :smile:

)