Chemistry paper 3 confusing question...Help!?

[therealhamzakhan]

Hello...I have a chemistry question.
It is Q5b M/J 2009
http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s09_qp_3.pdf
The markscheme doesn't say much...so I'm pretty lost about this question..can you help me out?

 

[therealhamzakhan]

I still dont understand mate...The question stated that the HEIGHT of the precipitate was 16mm(not the amount)
If you could do this question in steps, it would be great.