1.Why do we need to cube root if the question want "mean separation"of particle or atom?
2. A spherical drop of oil of diameter of 0.90mm spreads out on the surface of some water to form a circular patch of diameter 18 cm. Assuming that the oil patch is one oil molecule thick, estimate the length (or mean diameter) of an oil molecule.

Question

1.Why do we need to cube root if the question want "mean separation"of particle or atom?
2. A spherical drop of oil of diameter of 0.90mm spreads out on the surface of some water to form a circular patch of diameter 18 cm. Assuming that the oil patch is one oil molecule thick, estimate the length (or mean diameter) of an oil molecule.

unklerhaukus · Answer

cube root might have something to do with volume

unklerhaukus · Answer

$$V_{sphere}=\frac 43\pi r^3\qquad\qquad A_{circle}=\pi r^2\qquad r=\frac d2$$