Chemistry Excess reactions

[Saturation]

Hi everyone!
Can someone please explaning to me how to calculate excess amounts in reactions such as Question 7 in this paper:

http://www.xtremepapers.net/CIE/Cambridge IGCSE/0620 - Chemistry/0620_w08_qp_03.pdf

Thank you guys! :mrgreen:

 

[Saturation]

Anyone? :shock:

 

[SuperXDE]

I didn't start answering past papers yet , only reading till a "further notice" , Well... I made a self check yesterday on the same question paper ( 2nd Variant ) ¬¬ , I think it is related to the ratio in Carbon Dioxide , just calculate how much volume does carbon occupy of butane and how much volume needed to react with it... and the same... However I am not sure .... not at all -_-"