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Pre Lab: Freezing Point Experiment 1) Define: Colligative Properties. 2
Pre Lab: Freezing Point Experiment 1) Define: Colligative properties. 2) List four Colligative properties. 3) Define: Molal freezing point depression constant, Kf. 4) Does the value of Kf depend on the nature of ( solvent, or solute)?_________ 5) a) Show a freezing point of 6.00 °C on a cooling curve for a pure solvent. temperature time b) If the freezing point of a pure solvent is 6.00 °C, will the solvent which is contaminated with a soluble material have a freezing point (higher than, lower than, or same as) 6.00 °C ? Answer: _________. Explain:_______________________________________________________ c) Show a freezing point on the cooling curve for the above contaminated solvent. temperature time 6) Assume you had used a well calibrated thermometer to measure the freezing point of a solvent, can you tell from the cooling curve if the solvent is contaminated with soluble material?______ How can you tell? a) ____________________ b) _____________________ (Next page) 7) Show the freezing point on a cooling curve for a solvent contaminated with insoluble material. temperature time 8) What is the relationship between ∆T and molar mass of solute? The larger the value of ∆T, the (larger, or smaller) the molar mass of the solute? 9) If some insoluble material contaminated your solution after it had been prepared, how would this effect the measured ∆Tf and the calculated molar mass of solute? Explain: _______________________________________________________ 10) If some soluble material contaminated your solution after it had been prepared, how -
Lab Colligative Properties Data Sheet Answers
Lab Colligative Properties Data Sheet Answers outspanning:Rem remains hedogging: praising she his disclosed reunionists her tirelessly agrimony and semaphore dustily. Sober too purely? Wiatt demonetising Rhombohedral lissomly. Warren The answers coming up in both involve transformations of salt component of moles of salt flux is where appropriate. Experiment 4 Molar Mass by Freezing Point Depression. The colligative property and answer the colligative properties? Constant is what property set the solvent not the solute. Laboratory Manual An Atoms First Approach illuminate the various Chemistry Laboratory. Wipe the colligative property of solute concentration of in touch the following sensors and answer to its properties multiple choice worksheet. Experiment 2 Graphical Representation of Data and the Use all Excel. Investigation of local church alongside lab partners from one middle or high underneath The engaging. For dilute solutions under ideal conditions A new equal to 1 and. Colligative Properties Study Guide Answers Colligative properties study guide answers. Students will characterize the properties that describe solutions and the saliva of acids and. Do colligative properties lab data sheets, see this conclusion of how they answer. Weber State University. Adding a lab. Stir well in data sheet of colligative effects. Strong electrolytes are a colligative properties of data sheet provided to. If no ally is such a referred solutions lab 33 freezing point answers book that. Chemistry Colligative Properties Answer Key AdvisorNews. Which a property. B Answering about 5-6 questions on eLearning for in particular lab You please be. Colligative Properties Chp14 13 13-Freezing Points of Solutions - leave a copy of store Data company with the TA BEFORE leaving lab 1124 No labs 121. -
Solution Is a Homogeneous Mixture of Two Or More Substances in Same Or Different Physical Phases. the Substances Forming The
CLASS NOTES Class:12 Topic: Solutions Subject: Chemistry Solution is a homogeneous mixture of two or more substances in same or different physical phases. The substances forming the solution are called components of the solution. On the basis of number of components a solution of two components is called binary solution. Solute and Solvent In a binary solution, solvent is the component which is present in large quantity while the other component is known as solute. Classification of Solutions Solubility The maximum amount of a solute that can be dissolved in a given amount of solvent (generally 100 g) at a given temperature is termed as its solubility at that temperature. The solubility of a solute in a liquid depends upon the following factors: (i) Nature of the solute (ii) Nature of the solvent (iii) Temperature of the solution (iv) Pressure (in case of gases) Henry’s Law The most commonly used form of Henry’s law states “the partial pressure (P) of the gas in vapour phase is proportional to the mole fraction (x) of the gas in the solution” and is expressed as p = KH . x Greater the value of KH, higher the solubility of the gas. The value of KH decreases with increase in the temperature. Thus, aquatic species are more comfortable in cold water [more dissolved O2] rather than Warm water. Applications 1. In manufacture of soft drinks and soda water, CO2 is passed at high pressure to increase its solubility. 2. To minimise the painful effects (bends) accompanying the decompression of deep sea divers. O2 diluted with less soluble. -
Chapter 9: Raoult's Law, Colligative Properties, Osmosis
Winter 2013 Chem 254: Introductory Thermodynamics Chapter 9: Raoult’s Law, Colligative Properties, Osmosis ............................................................ 95 Ideal Solutions ........................................................................................................................... 95 Raoult’s Law .............................................................................................................................. 95 Colligative Properties ................................................................................................................ 97 Osmosis ..................................................................................................................................... 98 Final Review ................................................................................................................................ 101 Chapter 9: Raoult’s Law, Colligative Properties, Osmosis Ideal Solutions Ideal solutions include: - Very dilute solutions (no electrolyte/ions) - Mixtures of similar compounds (benzene + toluene) * Pure substance: Vapour Pressure P at particular T For a mixture in liquid phase * Pi x i P i Raoult’s Law, where xi is the mole fraction in the liquid phase This gives the partial vapour pressure by a volatile substance in a mixture In contrast to mole fraction in the gas phase yi Pi y i P total This gives the partial pressure of the gas xi , yi can have different values. Raoult’s Law Rationalization of Raoult’s Law Pure substance: Rvap AK evap where Rvap = rate of vaporization, -
Δtb = M × Kb, Δtf = M × Kf
8.1HW Colligative Properties.doc Colligative Properties of Solvents Use the Equations given in your notes to solve the Colligative Property Questions. ΔTb = m × Kb, ΔTf = m × Kf Freezing Boiling K K Solvent Formula Point f b Point (°C) (°C/m) (°C/m) (°C) Water H2O 0.000 100.000 1.858 0.521 Acetic acid HC2H3O2 16.60 118.5 3.59 3.08 Benzene C6H6 5.455 80.2 5.065 2.61 Camphor C10H16O 179.5 ... 40 ... Carbon disulfide CS2 ... 46.3 ... 2.40 Cyclohexane C6H12 6.55 80.74 20.0 2.79 Ethanol C2H5OH ... 78.3 ... 1.07 1. Which solvent’s freezing point is depressed the most by the addition of a solute? This is determined by the Freezing Point Depression constant, Kf. The substance with the highest value for Kf will be affected the most. This would be Camphor with a constant of 40. 2. Which solvent’s freezing point is depressed the least by the addition of a solute? By the same logic as above, the substance with the lowest value for Kf will be affected the least. This is water. Certainly the case could be made that Carbon disulfide and Ethanol are affected the least as they do not have a constant. 3. Which solvent’s boiling point is elevated the least by the addition of a solute? Water 4. Which solvent’s boiling point is elevated the most by the addition of a solute? Acetic Acid 5. How does Kf relate to Kb? Kf > Kb (fill in the blank) The freezing point constant is always greater. -
Physical Chemistry
Subject Chemistry Paper No and Title 10, Physical Chemistry- III (Classical Thermodynamics, Non-Equilibrium Thermodynamics, Surface chemistry, Fast kinetics) Module No and Title 10, Free energy functions and Partial molar properties Module Tag CHE_P10_M10 CHEMISTRY Paper No. 10: Physical Chemistry- III (Classical Thermodynamics, Non-Equilibrium Thermodynamics, Surface chemistry, Fast kinetics) Module No. 10: Free energy functions and Partial molar properties TABLE OF CONTENTS 1. Learning outcomes 2. Introduction 3. Free energy functions 4. The effect of temperature and pressure on free energy 5. Maxwell’s Relations 6. Gibbs-Helmholtz equation 7. Partial molar properties 7.1 Partial molar volume 7.2 Partial molar Gibb’s free energy 8. Question 9. Summary CHEMISTRY Paper No. 10: Physical Chemistry- III (Classical Thermodynamics, Non-Equilibrium Thermodynamics, Surface chemistry, Fast kinetics) Module No. 10: Free energy functions and Partial molar properties 1. Learning outcomes After studying this module you shall be able to: Know about free energy functions i.e. Gibb’s free energy and work function Know the dependence of Gibbs free energy on temperature and pressure Learn about Gibb’s Helmholtz equation Learn different Maxwell relations Derive Gibb’s Duhem equation Determine partial molar volume through intercept method 2. Introduction Thermodynamics is used to determine the feasibility of the reaction, that is , whether the process is spontaneous or not. It is used to predict the direction in which the process will be spontaneous. Sign of internal energy alone cannot determine the spontaneity of a reaction. The concept of entropy was introduced in second law of thermodynamics. Whenever a process occurs spontaneously, then it is considered as an irreversible process. -
16.4 Calculations Involving Colligative Properties 16.4
chem_TE_ch16.fm Page 491 Tuesday, April 18, 2006 11:27 AM 16.4 Calculations Involving Colligative Properties 16.4 1 FOCUS Connecting to Your World Cooking instructions for a wide Guide for Reading variety of foods, from dried pasta to packaged beans to frozen fruits to Objectives fresh vegetables, often call for the addition of a small amount of salt to the Key Concepts • What are two ways of 16.4.1 Solve problems related to the cooking water. Most people like the flavor of expressing the concentration food cooked with salt. But adding salt can of a solution? molality and mole fraction of a have another effect on the cooking pro- • How are freezing-point solution cess. Recall that dissolved salt elevates depression and boiling-point elevation related to molality? 16.4.2 Describe how freezing-point the boiling point of water. Suppose you Vocabulary depression and boiling-point added a teaspoon of salt to two liters of molality (m) elevation are related to water. A teaspoon of salt has a mass of mole fraction molality. about 20 g. Would the resulting boiling molal freezing-point depression K point increase be enough to shorten constant ( f) the time required for cooking? In this molal boiling-point elevation Guide to Reading constant (K ) section, you will learn how to calculate the b amount the boiling point of the cooking Reading Strategy Build Vocabulary L2 water would rise. Before you read, make a list of the vocabulary terms above. As you Graphic Organizers Use a chart to read, write the symbols or formu- las that apply to each term and organize the definitions and the math- Molality and Mole Fraction describe the symbols or formulas ematical formulas associated with each using words. -
Colligative Properties of Solutions
V.N.V.N. KarazinKarazin KharkivKharkiv NationalNational UniversityUniversity MedicalMedical ChemistryChemistry ModuleModule 1.1. LectureLecture 55 ColligativeColligative propertiesproperties ofof solutionssolutions NatalyaNatalya VODOLAZKAYAVODOLAZKAYA [email protected] 11 FebruaryFebruary 20212021 Department of Physical Chemistry LLectureecture topicstopics √ Colligative properties of solutions √ Vapor pressure lowering √ Boiling-point elevation √ Freezing-point depression √ Osmosis √ Colligative properties of electrolyte solutions 2 ColligativeColligative propertiesproperties ofof solutionssolutions Colligative properties of solutions are several important properties that depend on the number of solute particles (atoms, ions or molecules) in solution and not on the nature of the solute particles. It is important to keep in mind that we are talking about relatively dilute solutions, that is, solutions whose concentrations are less 0.1 mol/L. The term “colligative properties” denotes “properties that depend on the collection”. The colligative properties are: ¾ vapor pressure lowering, ¾ boiling-point elevation, ¾ freezing-point depression, ¾ osmotic pressure. 3 ColligativeColligative propertiesproperties ofof solutions:solutions: VaporVapor pressurepressure loweringlowering If a solute is nonvolatile, vapor pressure of the solution is always less than that of the pure solvent and depends on the concentration of the solute. The relationship between solution vapor pressure and solvent vapor pressure is known as Raoult’s law. This law states that the vapor pressure of a solvent over a solution (p1) equals the product of vapor pressure of the pure solvent (p1°) and the mole fraction of the solvent in the solution (x1): p1 = x1p1°. 4 ColligativeColligative propertiesproperties ofof solutions:solutions: VaporVapor pressurepressure loweringlowering In a solution containing only one solute, than x1 = 1 – x2, where x2 is the mole fraction of the solute. Equation of the Raoult’s law can therefore be rewritten as (p1° – p1)/p1° = x2. -
COLLIGATIVE PROPERTIES Dr
SOLUTIONS-3 COLLIGATIVE PROPERTIES Dr. Sapna Gupta SOLUTIONS: COLLIGATIVE PROPERTIES • Properties of solutions are not the same as pure solvents. • Number of solute particles will change vapor pressure (boiling pts) and freezing point. • There are two kinds of solute: volatile and non volatile solutes – both behave differently. • Raoult’s Law: gives the quantitative expressions on vapor pressure: • VP will be lowered if solute is non-volatile: P is new VP, P0 is original VP and X is mol fraction of solute. 0 P1 1P1 • VP will the sum of VP solute and solvent if solute is volatile: XA and XB are mol fractions of both components. 0 0 PT APA BPB Dr. Sapna Gupta/Solutions - Colligative Properties 2 EXAMPLE: VAPOR PRESSURE Calculate the vapor pressure of a solution made by dissolving 115 g of urea, a nonvolatile solute, [(NH2)2CO; molar mass = 60.06 g/mol] in 485 g of water at 25°C. (At 25°C, PH2O = 23.8 mmHg) P P 0 H2O H2O H2O mol mol 485 gx 26.91 mol H2O 18.02 g mol mol 115 g x 1.915 mol urea 60.06 g 26.91 mol 0.9336 H2O 26.91 mol1.915 mol P 0.9392 x 23.8 mmHg 22.2 mmHg H2O Dr. Sapna Gupta/Solutions - Colligative Properties 3 BOILING POINT ELEVATION • Boiling point of solvent will be raised if a non volatile solute is dissolved in it. • Bpt. Elevation will be directly proportional to molal concentration. Tb Kbm • Kb is molal boiling point elevation constant. Dr. Sapna Gupta/Solutions - Colligative Properties 4 FREEZING POINT DEPRESSION • The freezing point of a solvent will decrease when a solute is dissolved in it. -
Simple Mixtures
Simple mixtures Before dealing with chemical reactions, here we consider mixtures of substances that do not react together. At this stage we deal mainly with binary mixtures (mixtures of two components, A and B). We therefore often be able to simplify equations using the relation xA + xB = 1. A restriction in this chapter – we consider mainly non-electrolyte solutions – the solute is not present as ions. The thermodynamic description of mixtures We already considered the partial pressure – the contribution of one component to the total pressure, when we were dealing with the properties of gas mixtures. Here we introduce other analogous partial properties. Partial molar quantities: describe the contribution (per mole) that a substance makes to an overall property of mixture. The partial molar volume, VJ – the contribution J makes to the total volume of a mixture. Although 1 mol of a substance has a characteristic volume when it is pure, 1 mol of a substance can make different contributions to the total volume of a mixture because molecules pack together in different ways in the pure substances and in mixtures. Imagine a huge volume of pure water. When a further 1 3 mol H2O is added, the volume increases by 18 cm . When we add 1 mol H2O to a huge volume of pure ethanol, the volume increases by only 14 cm3. 18 cm3 – the volume occupied per mole of water molecules in pure water. 14 cm3 – the volume occupied per mole of water molecules in virtually pure ethanol. The partial molar volume of water in pure water is 18 cm3 and the partial molar volume of water in pure ethanol is 14 cm3 – there is so much ethanol present that each H2O molecule is surrounded by ethanol molecules and the packing of the molecules results in the water molecules occupying only 14 cm3. -
Chapter 9 Ideal and Real Solutions
2/26/2016 CHAPTER 9 IDEAL AND REAL SOLUTIONS • Raoult’s law: ideal solution • Henry’s law: real solution • Activity: correlation with chemical potential and chemical equilibrium Ideal Solution • Raoult’s law: The partial pressure (Pi) of each component in a solution is directly proportional to the vapor pressure of the corresponding pure substance (Pi*) and that the proportionality constant is the mole fraction (xi) of the component in the liquid • Ideal solution • any liquid that obeys Raoult’s law • In a binary liquid, A-A, A-B, and B-B interactions are equally strong 1 2/26/2016 Chemical Potential of a Component in the Gas and Solution Phases • If the liquid and vapor phases of a solution are in equilibrium • For a pure liquid, Ideal Solution • ∆ ∑ Similar to ideal gas mixing • ∆ ∑ 2 2/26/2016 Example 9.2 • An ideal solution is made from 5 mole of benzene and 3.25 mole of toluene. (a) Calculate Gmixing and Smixing at 298 K and 1 bar. (b) Is mixing a spontaneous process? ∆ ∆ Ideal Solution Model for Binary Solutions • Both components obey Rault’s law • Mole fractions in the vapor phase (yi) Benzene + DCE 3 2/26/2016 Ideal Solution Mole fraction in the vapor phase Variation of Total Pressure with x and y 4 2/26/2016 Average Composition (z) • , , , , ,, • In the liquid phase, • In the vapor phase, za x b yb x c yc Phase Rule • In a binary solution, F = C – p + 2 = 4 – p, as C = 2 5 2/26/2016 Example 9.3 • An ideal solution of 5 mole of benzene and 3.25 mole of toluene is placed in a piston and cylinder assembly. -
9.2 Raoult's Law and Henry's
Chapter 9 The Behavior of Solutions 1 9.2 Raoult’s Law and Henry’s Law (1) Initially evacuated vessel at T liq. A (2) spontaneously evaporate until P in the vessel ° reaches the saturated vapor pressure of liq. A, p A, at T (3) a dynamic equilibrium established between the rate of evaporation of liq. A & the rate of condensation of vapor A. 2 9.2 Raoult’s Law and Henry’s Law • re(A) α the # of A atoms in the vapor phase, ° thus, rc(A) = kp A , and at equilibrium (9.1) • Similarly, pure liquid B (9.2) re(A) rc(A) liq. A 3 9.2 Raoult’s Law and Henry’s Law (A) the effect of the small addition of liquid B to liquid A Assume (1) the composition of the surface of the liquid = that of the bulk liquid, XA, (2) the sizes of A & B atoms comparable (9.3) (9.4) 4 9.2 Raoult’s Law and Henry’s Law • From (9.1) and (9.3) gives (9.5) and from (9.2) and (9.4) gives (9.6) • Raoult’s law: the vapor pressure exerted by a component i in a solution = (the mole fraction of i in the solution) X (the saturated vapor pressure of pure liquid i ) at T of the solution. 5 9.2 Raoult’s Law and Henry’s Law • Requirements: the intrinsic rates of evaporation of A and B ≠ f(comp. of the solution) i.e., the magnitudes of the A-A, B-B, and A-B bond energies in the solution are identical 6 9.2 Raoult’s Law and Henry’s Law (B) If A-B >> A-A and B-B and a solution of A in B is sufficiently dilute: A atom at the surface surrounded only by B, A in a deeper potential E well than are the A atoms at the surface of pure liq… difficult to be lifted to vapor, evaporation rate is decreased to re(A) to re’(A) 7 9.2 Raoult’s Law and Henry’s Law (9.7) re(A) > re’(A) (9.8) ’ (9.9) • A similar consideration of dilute solutions of B in A gives ’ (9.10) • (9.9),(9.10) : Henry’ law 8 9.2 Raoult’s Law and Henry’s Law Beyond a critical value of XA, re’(A) becomes composition- dependent.