Mixtures and Solutions

Get seated. Get out notebooks and begin notes.

Mixtures and Solutions• A mixture is a combination

of two or more components thatare NOT chemically combined,and retain their identities.

Mixtures can be physically separated. The identities of the substances DO NOT change.A homogeneous mixture is also called a

solution.

Mixtures• When a mixture’s components are easily

recognizable, such as pizza, it is called a heterogeneous mixture.

• In a homogeneous mixture suchas chocolate milk, the component particles cannot be distinguished,even though they still retain theiroriginal properties.

Mixtures• Common Techniques for Separating Mixtures

Distillation – separates a mixture based on boiling points of the component.

Examples :saltwatercrude oil into gasoline and kerosene

Magnet – separates iron from other objects.

Centrifuge – spins and separates according to densities.

Solutions• A mixture that appears to be a single

substance but is composed of particles of two or more substances that are distributed evenly amongst each other.

A solution may be liquid, gaseous, or solid.Examples of solutions

Liquid - seawaterGas - airSolid - alloys

Parts of a Solution•SOLUTE – the part of a solution that is being dissolved (usually the lesser amount)•SOLVENT – the part of a solution that dissolves the solute (usually the greater amount)•Solute + Solvent = Solution

Solute

liquid

Solvent

solid

Example

Mercury in gold,Hexane in wax

solid solid Steel, Brass’Alloys,

gas solid Hydrogen into metals

solid liquid Sugar, Salt, Tea, Kool-Aide

liquid liquid Mixed drinks, Paint thinners.

gas liquid Soft drinks****, oxygen in water.

gas Gas Air

Solutions• Dissolving – The process in which particles of substances separate and spread evenly amongst each other.

• Solute – substance that is dissolved. A solute is soluble, or able to dissolve.

• A substance that is insoluble is unable to dissolve, forms a mixture that is not homogeneous, and therefore NOT a solution.

• Solvent – substance in which solute is dissolved.

DefinitionsDefinitionsSolutions can be classified as Solutions can be classified as

saturatedsaturated or or ununsaturated or saturated or super-saturatedsuper-saturated..

A A saturatedsaturated solution contains the solution contains the maximum quantity of solute that maximum quantity of solute that dissolves at that temperature.dissolves at that temperature.

An An unsaturatedunsaturated solution contains solution contains less than the maximum amount less than the maximum amount of solute that can dissolve at a of solute that can dissolve at a particular temperatureparticular temperature

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DefinitionsDefinitionsSUPERSATURATED SOLUTIONSSUPERSATURATED SOLUTIONS

contain more solute than is contain more solute than is possible to be dissolvedpossible to be dissolved

Supersaturated solutions are unstable. Supersaturated solutions are unstable. The supersaturation is only The supersaturation is only temporary, and usually temporary, and usually accomplished in one of two ways:accomplished in one of two ways:

1.1. Warm the solvent so that it will Warm the solvent so that it will dissolve more, then cool the dissolve more, then cool the solution solution

2. Evaporate some of the solvent carefully so that the solute does not solidify and come out of solution.

Solubility

• The solubility of a solute is the amount of solute needed to make a saturated solution using a given amount of solvent at a certain temperature.

• Solubility is usually expressed in grams of solute per 100 ml of solvent (g/100ml)

• Three (3) methods that affect solubility– Mixing, stirring, or shaking– Heating– Crushing or grinding

Suspension• A mixture in which particles ofa material are dispersed through-out a liquid or gas but are largeenough that they settle out.

– Particles are insoluble, so they DO NOT dissolve in the liquid or gas.

– Particles can be separated using a filter.• Examples:• Salad dressing• Medicines that say“shake well before use”

Colloids• A mixture in which the particles are

dispersed throughout but are not heavy enough to settle out.

• Made up of solids, liquids and gases.– Examples :

• Mayonnaise• Stick deodorant• Milk• Jello• Whipped cream• Peanut butter

My Quickie Definitions

• Unsaturated – Can hold some more• Saturated – Can’t hoolllddd nooo moorre• Super-saturated – Found a way to make it

hold more• Solubility – ability to be dissolved