Mixtures and Solutions

Mixtures and Solutions

• A mixture is a combinationof 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 such

as chocolate milk, the component particles cannot be distinguished,

even though they still retain their

original 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

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.

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