In a micellar solution of a soap, the critical micelle concentration is $1.0 \times 1 0^{- 3} M$ and each micelle contains 80 soap anions. Assuming that all soap above the CMC is present in micelles, find the micelle concentration in mM (millimolar) for a total soap concentration of $0.0251 M$ , to two decimals.

Numerical answer type, answer in mM, tolerance 0.01.

Answer: 0.3 mM

Soap present in micelles = total minus CMC =

0.0251 - 0.0010 = 0.0241 M

. Micelle concentration =

0.0241/80 = 3.0125 \times 1 0^{- 4} M

. This is

0.30 mM

to two decimals.