Mixtures Ch4.3 8th Pdf

Mixtures Chapter 4 Section 3



    

Describe the 3 properties of mixtures Describe 4 methods of separating the parts of a mixture Analyze a solution in terms of its solute and solvent Explain how concentration affects a solution Describe the particles in a suspension Explain how a colloid differs from a solution and a suspension

Objectives



A combination of 2 or more substances that are not chemically combined



No chemical change occurs



Each substance keeps its identity



You cannot always see all components of a mixture

Properties of Mixtures



Not all mixtures are easy to separate



Common ways to separate mixtures: ◦ Distillation  Based on boiling points of the components

◦ Magnet  Elements that are attracted separate out

◦ Centrifuge  Separates mixtures by the densities of the components

Separating Mixtures

http://blog.crispen.org/images/distillation.jpg

Distillation

http://image.tutorvista.com/content/chemistry-concepts/magnetic-separation-process.jpeg

Magnetic separation of Mixtures

http://upload.wikimedia.org/wikipedia/commons/1/11/Blood-centrifugation-scheme.png

http://3.bp.blogspot.com/_xW3FQUQ2DYI/Rp4DF1r_0HI/AAAAAAAAAhY/B5MzdxVSV6I/s400/centrifugation.png

Centrifuge



Compound: specific mass ratio



Mixture: no definite ratio



Ex: Granite pg. 100 Fig. 3 in text

Ratio of Components in a Mixture

Mixtures

Compounds

Made of elements, compounds, or both

Made of elements

No change in original properties of components

Change in original components

Separated by physical means

Separated by chemical means

Formed using any ratio of components

Formed using a set ratio of components

Mixtures vs. Compounds

A mixture that appears to be a single substance  2 or more substances distributed evenly: dissolving 



Solute: the substance that is dissolved



Solvent: the substance in which the solute is dissolved

Solutions



Soluble: able to dissolve



Insoluble: Unable to dissolve



Ex: salt water is a solution (apply the vocabulary)



When 2 liquids or 2 gases form a solution, the largest amount of substance is the solvent

Solutions

Solutions: apply your vocabulary

States

Examples

Gas in gas

Dry air (oxygen in nitrogen)

Gas in liquid

Soft drinks (CO2 in water)

Liquid in liquid

Antifreeze (alcohol in water)

Solid in liquid

Salt water (NaCl in water)

Solid in solid

Brass (Zn in Cu)

Examples of Solutions



Particles are so small they never settle out



Cannot be removed by filtering



Particles are so small they do not scatter light

Particles in Solutions



Amount of solute dissolved in a solvent



Expressed in g/mL of solvent



Concentrated or dilute

Concentration of Solutions http://wwwsci.seastarchemicals.com/images/faq_co3.jpg



The maximum amount of solute that can dissolve



The ability of a solute to dissolve in a solvent at a certain temperature

Solubility



Most solids are soluble in liquids at higher temperatures



Gases become less soluble in liquids as the temperature increases



Ex: soft drinks going flat at high temps

Dissolving Gases in Liquids http://romunov.blogsome.com/images/kozarec.jpg



Mixing



Heating



Crushing

Dissolving Solids Faster in Liquids http://www.thehomeherbalist.com/images/pic_pestal.jpg



A mixture in which the particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out



Can be separated through a filter



Ex: snow globe

Suspensions http://seattlest.com/attachments/seattle_courtney/snow-globe.jpg



Mixtures that have properties between solutions and suspensions



Particles are dispersed throughout but not heavy enough to settle



Ex: milk, mayonnaise, stick deodorant, gelatin, whipped cream

Colloids



Small than particles in suspension, but can scatter light



Cannot be separated by filtration



Particles are small enough to pass through a filter

Colloids http://www.science4u.info/virtuallab/_images/image_aut_nep_science.gif



Which of the following is not a solution: air in a scuba tank, muddy water, a soft drink, or salt water?



When iodine is dissolved in alcohol, which is the solute, and which is the solvent?

Quick Quiz