Composition of Composition of MatterMatter

Chapter 17 section 1Chapter 17 section 1

Substances A substance is something that can not be

broken down and still maintain its original characteristics/properties Elements are examples of a substance Compounds are examples of a substance

Difference Between Element Difference Between Element and Compound and Compound

Element-Combination of like atomsElement-Combination of like atoms Entire substance is made of the same Entire substance is made of the same

type of atomtype of atom Example-aluminum foilExample-aluminum foil

Compound-A substance in which two Compound-A substance in which two or more atoms are combined in a or more atoms are combined in a fixed proportion to become stablefixed proportion to become stable Example-HExample-H22OO

MixturesMixtures

A material made up of 2 or more A material made up of 2 or more substancessubstances Mixtures do not always combine the same Mixtures do not always combine the same

proportionsproportions Example-SaltwaterExample-Saltwater

Mixtures can be separatedMixtures can be separated Example/Question-What happens when you boil Example/Question-What happens when you boil

salt watersalt water As the water evaporates the salt is left behindAs the water evaporates the salt is left behind

Types of MixturesTypes of Mixtures

There are 3 different types of mixturesThere are 3 different types of mixtures1.1. Homogenous mixture-contains 2 or more Homogenous mixture-contains 2 or more

gaseous, liquid, or solid substances that are gaseous, liquid, or solid substances that are evenly blendedevenly blended

– ExamplesExamples– Coffee with milk and sugar (that has been dissolved)Coffee with milk and sugar (that has been dissolved)

– Shows diffusion of moleculesShows diffusion of molecules– Sugar and salt mixture that is mixed up evenlySugar and salt mixture that is mixed up evenly

– Homogenous mixtures create a solutionHomogenous mixtures create a solution– Solution-particles so small that they cant be seen without Solution-particles so small that they cant be seen without

the use of tools (microscope)the use of tools (microscope)

Types of Mixtures (continued)Types of Mixtures (continued)

2.2. Heterogeneous mixture-A mixture in which Heterogeneous mixture-A mixture in which materials are not evenly blendedmaterials are not evenly blended

– Sometimes they can be easily separated (not always)Sometimes they can be easily separated (not always)

– Example-a pizza is made up of crust, sauce, Example-a pizza is made up of crust, sauce, cheese and pepperonicheese and pepperoni

– Certain types of cereal-Raisin bran or Lucky Certain types of cereal-Raisin bran or Lucky charmscharms

– Some heterogeneous mixtures will separate over Some heterogeneous mixtures will separate over time time – Heterogeneous mixtures that will settle = suspensionHeterogeneous mixtures that will settle = suspension– Example-River carrying dirt or sand Example-River carrying dirt or sand

Types of Mixtures (continued)Types of Mixtures (continued)

3.3. Colloids-contains particles in varying Colloids-contains particles in varying proportions (heterogeneous) but particles will proportions (heterogeneous) but particles will not settle over timenot settle over time

– Examples–Fog (water particles suspended in air), Examples–Fog (water particles suspended in air), hair gel, and some shampooshair gel, and some shampoos

– Test for colloids using the Tyndall effectTest for colloids using the Tyndall effect– Tyndall effect is the scattering of light as it passes through Tyndall effect is the scattering of light as it passes through

a colloida colloid– You can see the beam because the particles in the You can see the beam because the particles in the

mixture are big enough to cause the light to scatter mixture are big enough to cause the light to scatter