please solve a,b ,c,d ,e and f solve all parts.

Q. What is the difference between molarity and molality of a solution? b. An aqueous solution contains 500 ppm of salt. What is the mass fraction of the salt? e. Define single pass conversion and overall conversion of a reactant. d. Explain how to calculate percent excess reactant. e. Justify the need for purging in chemical processes. f. What is a by-pass stream