Using Freezing Point to determine Molar Mass Objectives: To measure freezing points of known concentrations of solutions To use freezing point to determine.

Slides:

Advertisements

Similar presentations

CALCULATIONS INVOLVING COLLIGATIVE PROPERTIES

Advertisements

Molecular Mass by Freezing Point Depression Background Vapor Pressure  The melting and freezing points for a substance are determined by the vapor pressure.

Colligative Properties. How does the solute change the properties of the solvent? Consider aqueous solutions. Solvent = water. How do the properties of.

Colligative Properties Honors Chemistry Unit 8 Chapter 15.

Colligative Properties (solutions)

Calculations Involving Colligative Properties. Introduction We now understand colligative properties. To use this knowledge, we need to be able to predict.

Colligative Properties of Solutions Colligative properties = physical properties of solutions that depend on the # of particles dissolved, not the kind.

Colligative Properties of Solutions. How do you get from this…

Molarity and Molality.

Chapter 25. High surface tension, low vapor pressure, and high boiling points.

A brief introduction to freezing point depression THE COLLIGATIVE PROPERTIES OF MOLALITY AND FREEZING POINT DEPRESSION grownextgen.org.

Colligative Properties. Properties that depend upon the concentration of solute particles are called colligative properties. Generally these properties.

Solutions and their Behavior Chapter Identify factors that determine the rate at which a solute dissolves 2. Identify factors that affect the solubility.

1 Colligative Properties of Solutions Colligative properties are properties that depend only on the number of solute particles in solution and not on the.

Concentration Units Continued M = moles of solute liters of solution Molarity (M) Molality (m) m = moles of solute mass of solvent (kg) 12.3.

Chapter 9 Solution Concentrations and Colligative Properties.

III. Colligative Properties (p )

II III I IV. Colligative Properties of Solutions (p. 498 – 504) Ch. 14 – Mixtures & Solutions.

UNIT 9 Molality & Colligative Properties. Molarity is the most widely used form of quantitative concentration, but it is not the only one. There are actually.

Topic: Solutions Aim: What is another way to calculate concentration? DN: What is the formula for molarity?

II III I C. Johannesson III. Colligative Properties (p ) Ch. 13 & 14 - Solutions.

Colligative Properties. _______________ – physical properties of solutions that are affected only by the number of particles NOT the identity of the solute.

Calculations Involving Colligative Properties Freezing Point Depression and Boiling Point Elevation Calculations.

Solutions.  Colligative Property  property that depends on the concentration of solute particles, not their identity.

Lab Notebooks Courtesy of Pleasant Valley High School Chemistry.

Solutions --don’t worry—we’ll have problems to go with them.

Chapter 13 Section 5: Colligative Properties

Molar Mass and Freezing Point Depression Lab Prep.

Chapter 14 Ions in Aqueous Solutions & Colligative Properties.

Concentration Units The concentration of a solution is the amount of solute present in a given quantity of solvent or solution. Percent by Mass x 100%

Mini-Unit: Colligative Properties

Review To join clicker to class today: – Turn on the Clicker (the red LED comes on). – Push “Join” button followed by “20” followed by the “Send” button.

Monday Warm Up Find the molarity of a solution in which 5.5 mol of CaCl 2 is dissolved to make 2 L aqueous CaCl 2 solution. Find the molarity of a solution.

Review A solution is a homogeneous mixture.

Discussion: Colligative Properties Students will be able to: Explain how dissolved solutes affect the boiling and freezing points of solutions.

COLLIGATIVE PROPERTIES OF SOLUTIONS. Colligative Properties  A property that depends only upon the number of solute particles, and not upon their identity.

III. Colligative Properties

COLLIGATIVE PROPERTIES

 Solution Terminology: Solute, solvent, saturated, unsaturated, supersaturated, aqueous, homogeneous, heterogeneous, soluble, insoluble, miscible (alcohol.

1 Colligative Properties of Solutions. 2 Colligative Properties Colligative properties are physical properties of solutions that change when adding a.

Solutions Chapter 16. Solutions A solution is a homogenous mixture of 2 substances.

SOLUTIONS SUROVIEC SPRING 2015 Chapter 12. I. Types of Solution Most chemical reaction take place between ions/molecules dissolved in water or a solvent.

Colligative Properties. Doesn’t depend on identity, but number of particles Boiling Point Elevation (BPE) – addition of solute raises Boiling Point Freezing.

Chapter 18 Notes, part III Colligative Properties.

Changing melting and boiling points. Putting salt on sidewalks and roads in the winter helps because it lowers the freezing point of water by a few degrees.

Colligative Properties Test Chapter 15 Tuesday May 7, 2002.

Calculations Involving Colligative Properties. Objectives When you complete this presentation, you will be able to o calculate the molality of a solution.

Colligative Properties. ____________ – physical properties of solutions that are affected only by the number of particles NOT the identity of the solute.

$$$ Quiz $$$ Solutions. Liquids that are soluble in each other miscible.

SOLUTIONS A homogeneous mixture in which the components are uniformly intermingled.

COLLIGATIVE PROPERTIES

Do Now: What are the units for molarity?

Solutions Review.

V. Colligative Properties

Colligative Properties

(B) Adding a nonvolatile solute to a solvent decreases

How to Use This Presentation

Colligative Properties

III. Colligative Properties

Chapter 18 - Solutions.

* 07/16/96 SOLUTIONS *.

Colligative Properties of Solutions

DO NOW Pick up notes. Get out Molarity/Molality handout.

Ch. 3 & 7 – The Mole II. Concentration (p )

Concentration of Solute

III. Colligative Properties (p )

Boiling and Freezing Points

Colligative Properties of Solutions (chapter 16)

Chapter 13 Section 5: Colligative Properties

Colligative Properties

Presentation transcript:

Using Freezing Point to determine Molar Mass Objectives: To measure freezing points of known concentrations of solutions To use freezing point to determine molar mass of compounds

DataSolnFP ∆T fp Molality Molar Mass exp Molar Mass theor. % Error Water C 6 H 12 O 6 KNO 3

Class Data SolnFPFPFPFPFPFP C 6 H 12 O 6 KNO 3

The Set-up

Notes continued Solutions extend the liquid state of the solvent Solutions extend the liquid state of the solvent ID of solute is not important. NUMBER of particles in solution determines the effect ID of solute is not important. NUMBER of particles in solution determines the effect 1 mole of particles reduces the freezing temp of 1 liter of water by 1.85°C = “molal freezing point constant” K fp 1 mole of particles reduces the freezing temp of 1 liter of water by 1.85°C = “molal freezing point constant” K fp Same type of relationship exists for BP Same type of relationship exists for BP m (molality) = mols solute/kg solvent m (molality) = mols solute/kg solvent m can be solved by this formula: m=  T fp /K fp m can be solved by this formula: m=  T fp /K fp

Examples of how K fp is used Soluble ionic solids dissociate Soluble ionic solids dissociate C 12 H 22 O 11 C 12 H 22 O 11 NaCl NaCl CaCl 2 CaCl 2 Kfp is per particle (moles of particles), so must be multiplied by # of particles Kfp is per particle (moles of particles), so must be multiplied by # of particles

Calculations Use this equation to determine molar mass (exp): Use this equation to determine molar mass (exp): g solute (1000 g) (1 kg) g solvent (1 kg) (mol solute)  determine theoretical molar mass

Whiteboard none none

Freezing Point Lab Conclusion 1. On a particle level, why do you think FP is depressed in solutions? 2. If you tested for BP, why would you have to boil pure water first to determine water’s BP? Note, we assumed FP of water to be zero celsius. 3. CaCl 2 is widely used to melt ice. a.Why does ice melt under the freezing point? b.Why is one mole of CaCl 2 more effective than one mole of NaCl? Write Summary....