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Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
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Ch.7 - Quantum Mechanics
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Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
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Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: Caffeine (C8H10N4O2) is a stimulant found in coffee and tea. A solution of caffeine in the solvent chloroform (CHCl3) has a concentration of 0.0510 m.Calculate the mole fraction of caffeine in the sol

Solution: Caffeine (C8H10N4O2) is a stimulant found in coffee and tea. A solution of caffeine in the solvent chloroform (CHCl3) has a concentration of 0.0510 m.Calculate the mole fraction of caffeine in the sol

Problem

Caffeine (C8H10N4O2) is a stimulant found in coffee and tea. A solution of caffeine in the solvent chloroform (CHCl3) has a concentration of 0.0510 m.

Caffeine consists of two fused rings with a six-membered ring with the points arranged vertically whose right side is shared by the lower left side of a five-membered ring. The six-membered ring has O as its upper left vertex and bottom point; all other vertices are C. The shared side is a double bond; the other sides are single bonds. The bottom point is single bonded to CH3; the lower left vertex is double bonded to O; the upper left vertex is single bonded to CH3; and the top point is double bonded to O. In addition to the shared side, the lower right side of the five membered ring is also a double bond; the other sides are single bonds. The point of the five member ring and the lower right vertex are N; the other vertices are C. The point is single bonded to CH3 and the upper right vertex is single bonded to H.

Calculate the mole fraction of caffeine in the solution.

Solution

We’re being asked to calculate for the mole fraction of caffeine (C8H10N4O2in the solution. 

The solution is made up of caffeine (C8H10N4O2) and chloroform (CHCl3) with a concentration of 0.0510 m. Since chloroform is the solvent, we can say that caffeine is the solute.


Mole Fraction (X) relates the moles of solute and solvent within a solution:

mole fraction (X)=mole of solutemole of solution


We’ll calculate the mole fraction of caffeine using the following steps:

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