Pure Substance, Mixtures, Solutions

Pure S ubs ta nce s & Mix tu r es

What is a

pu re su bsta nc e ?

Pu re Su bst ance  A substance in which there is only one type of particle.  The particles of a pure substance are alike no matter where they are found.  Ex: Particles of iron in a skillet are the same as the iron particles found in a meteorite

Ele me nt  Is a pure substance that cannot be separated into simpler substances by physical or chemical means.  It only has one type of particle

Comp ounds  A pure substance composed of two or more elements that are chemically combined.  Salt- Sodium & Chlorine  Water- hydrogen & oxygen  Sugar- carbon, hydrogen & oxygen  Baking soda- sodium, hydrogen, carbon, and oxygen.

Co mp ounds a ren't Random  The elements that make up a compound join in a specific ratio according to their masses.  Water  1g hydrogen to 8g oxygen = 1:8 = 1/8

 Each compound has its own set or identifying properties different from the elements that it is formed from.

What is a

mixt ur e ?

Mix ture  Is a combination of two or more substance that are not chemically combined.  The substance in a mixture retain their identity.  Ex: pizza, salt water

Mix tures a re either:  Heterogeneous:  In a heterogeneous mixture you can see the different substances that make up the mixture OR

 Homogeneous:  In a homogenous mixture you can not tell the difference between the substances that make up the mixture

How d o yo u se para te a mixture ?  By: Physical separation (take topping off pizza) Distillation (based on boiling points) A magnet (certain metals) A centrifuge (separates by density) Filter (solid particles) Evaporation (sodium chloride & water)

So lutions  Are mixtures that appear to be a single substance.  They are still composed of two or more substance but they are distributed evenly amongst each other.  They are homogeneous.

Parts of a Solutio n  Solute- The substance that is dissolved  Ex: salt

 Solvent- The substance in which the solute is dissolved in.  Ex: Water

 Salt is soluble in water

 When two liquids or gasses for a solution the substance of greater volume is the solvent.

Oth er t yp es o f Mix tures:

 Suspensions: A mixture in which particles or a material are dispersed throughout a liquid or gas but are large enough that they settle out.  Colloids: A mixture in which particles are dispersed throughout but are not heavy enough to settle out. Ex: Milk, Jell-O, Fog  They cannot be separated by filtration the particles are to small

More o n Mix ture s:  Concentration: measures the amount of a solute dissolved in a solvent.  Solutions can be described as being concentrated or diluted.

 Solubility: The amount of solute needed to make a saturated solution ( grams/ 100mL)  Saturated: A solution that contains all the solute is can hold at a given temperature.  Unsaturated: A solution that contains less solute then it can hold at a given temperature.

Mix tures Vs. Co mpounds Mixtures

Compounds

Components are elements, compounds, or both.

Components are elements.

Components keep their Components lose their original properties. original properties. Separated by physical means. Separated by chemical means. Formed using any ratio of components

Formed using a set mass ratio of components.