北京化工大学：《物理化学》课程电子教案（理科双语）Chapter 11 Colloid Chemistry

Colloids PDF文件使用"pdfFactory Pro”试用版本创建wm,fineprint..com,cn

Colloids PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn

What is a Colloid? Solution Suspension homogeneous heterogeneous mixture mixture particles are particles visible, molecules settle out Size100 nm Colloid size 1-100 nm particles invisible, remain suspended PDF文件使用"pdfFactory Pro”试用版本创建mm,fineprint..com,cn

What is a Colloid? Solution homogeneous mixture particles are molecules Size100 nm Colloid size 1-100 nm particles invisible, remain suspended PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn

Characteristics of Colloids Consist of a continuous phase and a dispersed phase Classified in terms of dispersed substance(solid,liquid, gas)in dispersing medium (solid,liquid,gas) Dispersed phase 1-100 nm particles: Large surface area to volume ratio Size appropriate for scattering light (Tyndall effect) Thermodynamically unstable,so need some way to keep PDF文件使用"pdfFactory Pro”试用版本创建m,fineprint.com,cn

Characteristics of Colloids • Consist of a continuous phase and a dispersed phase • Classified in terms of dispersed substance (solid, liquid, gas) in dispersing medium (solid, liquid, gas) • Dispersed phase 1-100 nm particles: – Large surface area to volume ratio – Size appropriate for scattering light (Tyndall effect) – Thermodynamically unstable, so need some way to keep PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn

Characteristics of Colloids Very large surface area May have a charged surface Scatter light(Tyndall effect) Classified in terms of dispersed substance(s, 1,g)in dispersing medium (s,1,g) PDF文件使用"pdfFactory Pro”试用版本创建ww.fineprint.com.cn

Characteristics of Colloids • Very large surface area • May have a charged surface • Scatter light (Tyndall effect) • Classified in terms of dispersed substance (s, l, g) in dispersing medium (s, l, g) PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn

Classification of Colloids Dispersed Dispersing Name of Common Examples Phase Medium Colloidal System Liquid Gas Liguid Aerosol Mist,clouds,fog Solid Gas Aerosol Dust,smoke Gas Liguid Foam Suds,whipped cream Liquid Liquid Emulsion Cream,milk,mayo Solid Liquid Sol Paints,jellies, sewage Gas Solid Solid Foam Marshmallow Liquid Solid Solid Emulsion Butter,cheese Solid Solid Solid Sol Opals,some alloys PDF文件使用"pdfFactory Pro”试用版本创建ww,fineprint.com,c里

Classification of Colloids Dispersed Phase Dispersing Medium Name of Colloidal System Common Examples Liquid Gas Liquid Aerosol Mist, clouds, fog Solid Gas Aerosol Dust, smoke Gas Liquid Foam Suds, whipped cream Liquid Liquid Emulsion Cream, milk, mayo Solid Liquid Sol Paints, jellies, sewage Gas Solid Solid Foam Marshmallow Liquid Solid Solid Emulsion Butter, cheese Solid Solid Solid Sol Opals, some alloys PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn

Scatter light ---Tyndall effect 入：400~760nm size:1~100 nm A >size----Scatter light 9元7℃"-mXl+cos)l ,2 +no 1c1/入4 PDF文件使用"pdfFactory Pro”试用版本创建曦ifineprint.com,cn

Scatter light ---Tyndall effect λ：400~760nm size：1~100 nm λ >size----Scatter light 0 2 2 0 2 2 0 2 4 2 2 2 ( )(1 cos ) 2 9 I n n n n l V C I a l p + + - = I ∝1/λ 4 PDF 文件使用 "pdfFactory Pro" 试用版本创建 Ì駿Ì www.fineprint.com.cn

Characteristics of Kinetics .Brown Movement .Diffuse .Sedimentation and its Equilibrium PDF文件使用"pdfFactory Pro”试用版本创建ww,fineprint.com.c四

Characteristics of Kinetics •Brown Movement •Diffuse •Sedimentation and its Equilibrium PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn

Characteristics of Electricity .Electrophoresis M PDF文件使用"pdfFactory Pro”试用版本创建m,fineprint.com,cn

Characteristics of Electricity •Electrophoresis PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn

atural Instability of Colloids The interaction between molecules or one substance and another is almost always more unfavourable than the interaction of one substance with itself -e.g.,like dissolves like' A system will move in such a way as to eliminate unfavourable interactions i.e,to eliminate surfaces One big lump of clay in a bucket of water is thermodynamically much more stable than clay particles dispersed throughout the water PDF文件使用"pdfFactory Pro”试用版本创建m,fineprint.com,c四

Natural Instability of Colloids • The interaction between molecules or one substance and another is almost always more unfavourable than the interaction of one substance with itself – e.g., ‘like dissolves like’ • A system will move in such a way as to eliminate unfavourable interactions – i.e, to eliminate surfaces • One big lump of clay in a bucket of water is thermodynamically much more stable than clay particles dispersed throughout the water PDF 文件使用 "pdfFactory Pro" 试用版本创建 ÿwww.fineprint.com.cn

Stabilisation of Colloids If they have electrical charges on their surfaces, they will repel one another...(like charges repel) PDF文件使用"pdfFactory Pro”试用版本创建，fineprint.com,cn

Stabilisation of Colloids • If they have electrical charges on their surfaces, they will repel one another... (like charges repel) PDF 文件使用 "pdfFactory Pro" 试用版本创建 Ìwww.fineprint.com.cn ÿ