A combination of two or more substances NOT chemically combined Mixtures A combination of two or more substances NOT chemically combined

Types of Mixtures Solutions Suspensions Colloids

Mixtures … Each substance keeps its own identity Components do not have a definite ratio Can be separated using physical means

More characteristics Mixtures can be made up of elements, compounds or both A mixture could be a pizza, a rock, air, lemonade, colloids a solution…..

2 Kinds of Mixtures Heterogenous mixtures is not uniform in composition(not same type of particle throughout). If you were to sample one portion of such a mixture, it’s composition would be different from that of another portion. e.g. Salad dressing

2nd types of mixture Homogenous mixtures Is the type of mixture that is uniform in composition (same type of particle through-out). If you were to sample one portion of such a mixture, it’s composition would be similar to that of another portion.e.g. juice

New Terms Concentrated Dilute Soluble Insoluble Saturated, unsaturated

1. Solutions Appears like one substance, but made up of 2 or more substances; Homogenous Ex. Salt water: Water: solvent Sodium chloride: solute

Vocabulary Concentrated: Has more solute Dilute: Has less solute. Saturated solution: Contains all the solute it can take at given temp.

-Substance in which solute dissolves E.g. Salt water: Solvent: Is water -Substance in which solute dissolves Usually the larger quantity Water=Universal Solvent

Solute: Is Sodium Chloride -Substance that dissolves in solvent - Usually the lesser quantity

Unsaturated: Solvent can dissolve more solute Soluble: Can dissolve Insoluble: Cannot dissolve

Types of Solutions Gas in gas: air Gas in liquid: pool chlorine Liquid in gas: water vapor Liquid in liquid: antifreeze Solid in solid: alloys-steel Solid in liquid: salt water Solid in gas: smoke

Characteristics of Solutions Particles VERY small (ions) Cannot be filtered(pass thru’) Light passing through does not scatter (transparent) Solubility determines how much solute in a solvent

Concentration How much solute per unit of solvent 35 g. NaCl in 175 mL water -concentration = 35/175 g/mL = 0.2g/mL

Solubility of a solute Amount of solute needed to make a saturated solution in a given solvent at a given temperature.

Solubility Rules How MUCH solute can be dissolved? Depends on temperature: solubility of solids in liquids increases as temperature increases Is opposite for gases! e.g. soda…

Prediction: Which of these is a solution? Air? Soft Drinks? Ocean water? Antifreeze? Brass? Rocks? Popcorn and Salt in a bag?

Q: What did the compound say to the solution? Check this out…  Q: What did the compound say to the solution? A: You’re all MIXED UP!

2. Suspensions a mixture where the particles are large enough to settle out. Separated by filtering Examples: salad dressing, blood

3. Colloids Halfway between a solution and a suspension Particles can’t be filtered Particles can scatter light – The Tyndale Effect Examples: mayo, milk, gelatin, whipped cream

The Tyndale Effect Light passes straight through a solution(left) but is scattered by a colloid (right)

Characteristics Heterogeneous Each part of the mixture retains its own identity Parts of a mixture do not have a definite ratio Mixtures CAN be separated using physical methods

Ways to Separate Mixtures (physical methods): Distillation/Condensation Using a magnet Centrifuging Filtering Evaporation

Chemical Methods of breaking down Compounds Heat Electrolysis – pass an electric current through. E.g. electrolysis of water to H2 and O2 gases, salt to Na & Cl2 gas Chemical reactions – Carbonic acid(H2CO3) breaks down to CO2 an H2O, which can break down even further to C, O and H Cannot be broken with physical methods

Distillation in the Lab

Decantation Filtration Evaporation

I Understand … Comparing Mixtures and Compounds Compounds Mixtures Components are elements Components are elements, compounds or both Components lose their original properties Components keep their original properties Separated by chemical means Separated by physical means Formed using a set(fixed) mass ratio of components Formed using any mass ratio of components

Separation of a mixture Assignment How can we separate a mixture of Sand, Salt and Fe filings? What physical properties are being used? Design and Write a possible plan to Test it.