Slide 1 of 42 Chemistry 16.4. © Copyright Pearson Prentice Hall Slide 2 of 42 Calculations Involving Colligative Properties Cooking instructions often.

of 42 Chemistry 16.4

© Copyright Pearson Prentice Hall Slide 2 of 42 Calculations Involving Colligative Properties Cooking instructions often call for the addition of a small amount of salt to the cooking water. Dissolved salt elevates the boiling point of water. You will learn how to calculate the amount the boiling point of the cooking water rises. 16.4

© Copyright Pearson Prentice Hall Slide 4 of 42 Calculations Involving Colligative Properties > Molality and Mole Fraction The unit molality and mole fractions are two additional ways in which chemists express the concentration of a solution. 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Molality and Mole Fraction The unit molality (m) is the number of moles of solute dissolved in 1 kilogram (1000 g) of solvent. Molality is also known as molal concentration. 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Molality and Mole Fraction To make a 0.500m solution of NaCl, use a balance to measure 1.000 kg of water and add 0.500 mol (29.3 g) of NaCl. 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Molality and Mole Fraction Ethlylene Glycol (EG) is added to water as antifreeze. 16.4

© Copyright Pearson Prentice Hall Slide 12 of 42 Practice Problems Practice ProblemsFor Sample Problem 16.6 Problem Solving 16.29 Solve Problem 29 with the help of an interactive guided tutorial. for Sample Problem 16.6

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Molality and Mole Fraction The mole fraction of a solute in a solution is the ratio of the moles of that solute to the total number of moles of solvent and solute. 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Molality and Mole Fraction In a solution containing n A mol of solute A and n B mol of solvent B (X B ), the mole fraction of solute A (X A ) and the mole fraction of solvent B (X B ) can be expressed as follows. 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Freezing-Point Depression and Boiling-Point Elevation How are freezing-point depression and boiling-point elevation related to molality? 16.4

© Copyright Pearson Prentice Hall Slide 21 of 42 Calculations Involving Colligative Properties > Freezing-Point Depression and Boiling-Point Elevation The magnitudes of the freezing-point depression and the boiling-point elevation of a solution are directly proportional to the molal concentration (m), when the solute is molecular, not ionic. 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Freezing-Point Depression and Boiling-Point Elevation The constant, K f, is the molal freezing-point depression constant, which is equal to the change in freezing point for a 1-molal solution of a nonvolatile molecular solute. 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Freezing-Point Depression and Boiling-Point Elevation 16.4

of 42 © Copyright Pearson Prentice Hall Calculations Involving Colligative Properties > Freezing-Point Depression and Boiling-Point Elevation The constant, K b, is the molal boiling-point elevation constant, which is equal to the change in boiling point for a 1-molal solution of a nonvolatile molecular solute. 16.4

© Copyright Pearson Prentice Hall Slide 26 of 42 Calculations Involving Colligative Properties > Freezing-Point Depression and Boiling-Point Elevation Simulation 21 Discover the principle underlying the colligative properties of solutions.

© Copyright Pearson Prentice Hall Slide 39 of 42 16.4 Section Quiz. 1. What is the mole fraction of He in a gaseous solution containing 4.0 g of He, 6.5 g of Ar, and 10.0 g of Ne? a.0.60 b.1.5 c.0.20 d.0.11

© Copyright Pearson Prentice Hall Slide 40 of 42 16.4 Section Quiz. 2. The freezing point depression caused by a given concentration of a nonvolatile molecular solute a.depends on the solute. b.depends on the solvent. c.is always the same. d.cannot be determined.

© Copyright Pearson Prentice Hall Slide 41 of 42 16.4 Section Quiz. 3. What are the freezing and boiling points of a 0.1m solution of CaCl 2 in water? a.-0.2°C, 100.1°C b.-0.6°C, 100.1°C c.-0.6°C, 100.2°C d.-0.6°C, 99.8°C

© Copyright Pearson Prentice Hall Slide 42 of 42 16.4 Section Quiz. 4. Compared to the freezing point depression by ethylene glycol (C 2 H 6 O 2,) for a given solvent, the freezing point depression caused by the same molal concentration of CaCl 2 would be a.exactly the same. b.twice as large. c.three times as large. d.four times as large

END OF SHOW

Slide 1 of 42 Chemistry 16.4. © Copyright Pearson Prentice Hall Slide 2 of 42 Calculations Involving Colligative Properties Cooking instructions often.

Similar presentations

Presentation on theme: "Slide 1 of 42 Chemistry 16.4. © Copyright Pearson Prentice Hall Slide 2 of 42 Calculations Involving Colligative Properties Cooking instructions often."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Slide 1 of 42 Chemistry 16.4. © Copyright Pearson Prentice Hall Slide 2 of 42 Calculations Involving Colligative Properties Cooking instructions often.

Similar presentations

Presentation on theme: "Slide 1 of 42 Chemistry 16.4. © Copyright Pearson Prentice Hall Slide 2 of 42 Calculations Involving Colligative Properties Cooking instructions often."— Presentation transcript:

Similar presentations

About project

Feedback