Question 316: Properties of Matter

Question

Suppose you have taken a dilute solution of oleic acid in such a way that its concentration becomes 0.01 cm
3
of oleic acid per cm
3
of the solution. Then you make a thin film of this solution (monomolecular thickness) of area 4 cm
2
by considering 100 spherical drops of radius $${\left( {{3 \over {40\pi }}} ight)^{{1 \over 3}}} 	imes {10^{ - 3}}$$ cm. Then the thickness of oleic acid layer will be x $$	imes$$ 10
$$-$$14
m. Where x is ____________.

Accepted Answer

4t
T
= 100 $$ 	imes $$ $${4 \over 3}\pi {r^3}$$
= $$100 	imes {4 \over 3}\pi  	imes {3 \over {40\pi }} 	imes {10^{ - 9}}$$
= 10
-8
cm
3
$$ \Rightarrow $$ t
T
= 25 $$ 	imes $$ 10
-10
cm
= 25 $$ 	imes $$ 10
-12
m
t
0
= 0.01 t
T
= 25 $$ 	imes $$ 10
-14
m
$$ 	herefore $$ x = 25

Properties of Matter

Integer / Numeric Answer Type