The Student Room Group

rate Equation and Temperature

The rate equation for the hydrogenation of ethene
C2H4(g) + H2(g)-------------------> C2H6(g)
is Rate = k[C2H4]


At a fixed temperature, the reaction mixture is compressed to triple the original
pressure.
What is the factor by which the rate of reaction changes?
Original post by Qer
The rate equation for the hydrogenation of ethene
C2H4(g) + H2(g)-------------------> C2H6(g)
is Rate = k[C2H4]


At a fixed temperature, the reaction mixture is compressed to triple the original
pressure.
What is the factor by which the rate of reaction changes?


Do you know what the equation for the rate actually means?
Do you understand the use of the square brackets?
Reply 2
Original post by charco
Do you know what the equation for the rate actually means?
Do you understand the use of the square brackets?



Rate equations tell us how the rate is affected by the concentration of reactants at a particular temp
square brackets represent the concentration
Original post by Qer
Rate equations tell us how the rate is affected by the concentration of reactants at a particular temp
square brackets represent the concentration


OK

So if you compress the mixture to triple the pressure the concentration of both gases also triples. What happes to the rate?
Reply 4
Original post by charco
OK

So if you compress the mixture to triple the pressure the concentration of both gases also triples. What happes to the rate?


got it overall order of reaction is second
So rate increases by a square factor of 2 =9

f
i dont understand- why is it 9?
Original post by evelync12
i dont understand- why is it 9?

Because the overall order is 2,and the concentration is changed by 3, the rate change will be 3 squared = 9 ( because for 2nd order the rate is proportional to concentration squared)

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