Solution :
Assume that the diameter of the watch glass is 9.5 cm.
There are 10 drops of hexagon in 1 mL.
V = volume of hexagon in per drop =
mL per drop
V = 0.1 mL per drop
N = number of drops to form phospholipid layer
N = 39 (assumed)
= volume of hexagon required to form phospholipid layer
= V x N
= 0.1 x 39
= 3.9 mL
Since 1 mL = 1

∴
= 3.9
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d = diameter of the watch glass = 9.5 cm
A = area of one molecule


