[neon flash!]

really need help with the following question pls.
dont have a clue where to start
(a)
A film containing 6.3 × 10−5 g 1-decanol, CH3(CH2)9OH, spread on water was compressed into a monomolecular layer occupying an area of 0.24 m × 0.27 m, and a film containing 2.5 × 10−5 g 1-dodecanoic acid, CH3(CH2)11COOH, spread on water was compressed into a monomolecular layer occupying an area of 0.14 m × 0.17 m. Calculate the cross-sectional area and length of molecules of 1-decanol and 1-dodecanoic acid, given that their densities are 0.829 and 0.868 g cm−3, respectively.
[10]
(b)
Using the data given below, determine the following:
(i)
the work of cohesion for water and mercury,
[3]
(ii)
the work of adhesion between water and dodecane and between water and mercury,
[4]
(iii)
the initial spreading coefficient of dodecane, octan-1-ol and aniline on water.
[3]
Surface and interfacial tensions / N m−1 at 293.2 K
γ(Liquid/Air) γ(Water/Liquid)
Water 0.0726 -------
Dodecane 0.0254 0.0529
Octan-1-ol 0.0275 0.0085
Aniline 0.0429 0.0059
Mercury 0.484 0.426

[fledarmus]

Start at the beginning. The first part is basic geometry - what do you need to figure out how large each molecule is?