Ch.15 - Acid and Base EquilibriumWorksheetSee all chapters
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Ch.1 - Intro to General Chemistry
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Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
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Solution: Cocaine is a weak organic base whose molecular formula is C17H21NO4. An aqueous solution of cocaine was found to have a pH of 8.53 and an osmotic pressure of 52.7 torr at 15 oC.Calculate Kb for cocaine.

Solution: Cocaine is a weak organic base whose molecular formula is C17H21NO4. An aqueous solution of cocaine was found to have a pH of 8.53 and an osmotic pressure of 52.7 torr at 15 oC.Calculate Kb for cocain

Problem

Cocaine is a weak organic base whose molecular formula is C17H21NO4. An aqueous solution of cocaine was found to have a pH of 8.53 and an osmotic pressure of 52.7 torr at 15 oC.

Calculate Kb for cocaine.

Solution

We are being asked to calculate the Kb for a cocaine solution of which has a pH of 8.53 and an osmotic pressure of 52.7 torr at 15°C

Cocaine is a weak organic base whose molecular formula is C17H21NO4


Since we’re dealing with a weak base and Kb is an equilibrium expression, we will have to create an ICE chart to determine the equilibrium concentration of each species:

C17H21NOweak baseproton acceptor
H2O → will act as the weak acidproton donor


Equilibrium reaction:        C17H21NO4(aq) + H2O(l)  C17H21NO4H+(aq) + OH-(aq)

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