Ch.12 - SolutionsWorksheetSee all chapters
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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
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
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
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Sections
Solutions, Molarity and Intermolecular Forces
Henry's Law
Calculate Molarity
Mass Percent
Molality
Mole Fraction
The Colligative Properties
Additional Practice
Making Solutions
Freezing Point Depression
Colloid
Additional Guides
ppm
The Freezing Point Depression
Boiling Point Elevation
LearnAdditional Practice
Next SectionThe Colligative Properties

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

Understanding Mole Fraction

Concept #1:

Mole Fraction is depicted as moles of solute per moles of solution. 

 

Example #1: If the mole fraction of glucose, C6H12O6, in an aqueous solution is 0.320 what is the molarity? Density of the solution is 1.530 g/mL. 

Example #2: If the mole fraction of methanol, CH3OH, in an aqueous solution is 0.060 what is the molality? Density of the solution is 1.39 g/mL. 

Example #3:

Calculate the mole fraction of acetic acid, HC2H3O2, in a 27.13 mass % aqueous solution (d = 0.9883 g/mL). MW of HC2H3O2 is 60.054 g/mol. 

 

Previous SectionMolality
Next SectionThe Colligative Properties
Additional Problems
The molecular formula of Vitamin E (tocopherol is C29H50O2 (MW = 420.71). If the mole fraction of vitamin E in a methyl alcohol (CH3OH) solution is 0.002, what is the molality of the Vitamin E solution? a. none of the other answers is even close (within 10% error) b. 0.00273 c. 0.00503 d. 0.0625 e. 0.1570
If the mass of sodium chloride, NaCl (MW = 58.5 g/mol), is 40.0 g and the mass of water is 30.0 g, what is the mole fraction of NaCl in the solution?a. 0.291b. 0.60c. 0.40d. 40.0e. 0.240     What is the mass percent of NaCl in the solution in the previous question?a. 0.291b. 0.60c. 0.40d. 40.0e. 0.240
If the mass of sodium chloride, NaCl (MW= 58.5 g/mol), is 40.0 g and the mass of water is 30.0 g, what is the mole fraction of NaCl in the solution? a) 0.291 b) 0.60 c) 0.40 d) 40.0 e) 0.240   What is the mass percent of NaCl in the solution in the previous question? a) 0.291 b) 0.60 c) 0.40 d) 40.0 e) 0.240
The molecular formula of Vitamin E (tocopherol) is C29H50O2 (MW = 430.71). If the mole fraction of vitamin E in a methyl alcohol (CH3OH) solution is 0.002, what is the molality of the Vitamin E solution?a) none of the other answers is even close (within 10% error )b) 0.00273c) 0.00503d) 0.0625e) 0.1570
What is the mole fraction of NaCl in a solution that contains 40.0 g NaCl and 60.0 g H2O?a) none of the given answersb) 3.33c) 0.205d) 0.170e) 0.300
A solution is made by mixing equal masses of methanol CH 4O (MW = 32.01 g/mol) and ethanol C2H6O (MW = 46.02 g/mol). Determine the mole fraction of methanol. a) 0.129 b) 0.388c) 0.410d) 0.590
A solution is prepared by dissolving 38.6 g sucrose (C12H22O11) in 495 g of water.  Determine the mole fraction of sucrose if the final volume of the solution is 508 mL.A) 1.28 × 10 -3      B) 2.45 × 10 -3 C) 7.80 × 10 -2D) 4.09 × 10 -3 E) 7.23 × 10 -2
What is the mole fraction of water in 200 g of 95% (by mass) ethanol, C 2H5OH?Formula Molar Mass of C2H5OH is 46 g•mol –1.a) 0.050b) 0.12c) 0.56d) 0.88
Which of the following chemical terms is affected by temperature? MolalityMass percentMolarityMole fraction
A solution of sodium methoxide, NaOCH 3, in water has a mole fraction of 0.1750. What is the molality?
What is the mole fraction of ethanol, C 2H5OH, if 42.52 g of ethanol is added to 125.00 g of water?a. 0.480 b. 7.382c. 0.133d. 0.117e. 0.465
Calculate the mole fraction of total ions in an aqueous solution prepared by dissolving 0.400 moles of MgCl2 in 850.0 g of water.A. 0.00841B. 0.0270C. 0.00900D. 0.0248E. 0.0167
What is the mole fraction of Ethanol in a solution composed of 10 g Ethanol (C  2H6O), 10 g H2O, & 10 g CH3OH? A) 0.217B) 0.201C) 0.33D) 0.289E) 0.410
What is the mole fraction of methanol, CH 3OH, if 55.18 g of methanol are added to 208.00 g of water?A. 0.633B. 0.130C. 8.277D. 0.149E. 0.321
A concentrated solution of glucose (C6H12O6) in water 75.3 % glucose by mass. Calculate the mole fraction and the molarity of glucose solution. (The density of the solution is 1.03g/mL)
A solution is made by mixing equal masses of methanol, CH 4O, and ethanol, C2H6O.Determine the mole fraction of each component to at least three significant figures.
A solution of phosphoric acid was made by dissolving 10.0 g H 3PO4 in 100.0 mL water. The resulting volume was 104 mL. Calculate the density, mole fraction, molarity, and molality of the solution. Assume water has a density of 1.00 g/cm3.
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 solution.
Pentane (C5H12) and hexane (C6H14) form an ideal solution. At 25°C the vapor pressures of pentane and hexane are 511 and 150. torr, respectively. A solution is prepared by mixing 25 mL pentane (density, 0.63 g/mL) with 45 mL hexane(density, 0.66 g/mL).b. What is the composition by mole fraction of pentane in the vapor that is in equilibrium with this solution?
A solution is prepared by dissolving 38.6 g sucrose (C12H22O11) in 495 g of water.  Determine the mole fraction of sucrose if the final volume of the solution is 508 mL.
Determine the mole fraction of glucose, C6H12O6, (molecular weight 180.18) in a 1.86 M aqueous glucose solution given the density of the glucose solution is 1.38 g/cm3.a. 0.0311b. 0.0237c. 0.0324d. 0.0243e. 0.0480
In a 66.0-g aqueous solution of methanol, CH 4O, the mole fraction of methanol is 0.120. What is the mass of each component?a) Mass of CH4Ob) Mass of water
A solution was prepared by dissolving 39.0 g of KCl in 225 mL of water. Calculate the mole fraction of the ionic species KCl in the solution. Express the concentration numerically as a mole fraction in decimal form.